JP5422927B2 - Charging member, charging device, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a charging member, a charging device, a process cartridge, and an image forming apparatus.

  In recent years, image forming apparatuses such as printers and copying machines have been widely used, and techniques relating to various elements constituting such image forming apparatuses have also been widely used. Among image forming apparatuses that employ an electrophotographic method, an image carrier is charged using a charging device, and an electrostatic latent image having a potential different from the surrounding potential is formed on the charged image carrier. In many cases, a printed pattern is formed by forming the electrostatic latent image, and the electrostatic latent image formed in this way is developed with a developer containing toner, and finally transferred onto a recording medium. Recently, a process cartridge in which components of an image forming apparatus such as an image holding body and a charging device are set is on the market. By incorporating this process cartridge into the image forming apparatus, the image holding body Since a plurality of components including the charging device and the charging device can be collectively provided in the image forming apparatus, maintenance and the like have become easier.

  The charging device is an apparatus that performs an important function of charging the image holding member. The charging device of the contact charging method that directly contacts the image holding member to charge the image holding member and the image holding member are not in contact with each other. The charging device is roughly classified into two types, namely, a non-contact charging type charging device for charging the image holding member by corona discharge in the vicinity of the image holding member. In a non-contact charging system charging device, substances such as ozone and nitrogen oxides may be generated secondaryly by discharge, and recently, charging devices employing the contact charging system are increasing.

  The contact charging type charging device includes a charging member that is in direct contact with the surface of the image holding member and is driven to rotate in accordance with the movement of the surface of the image holding member to charge the image holding member. When the image holding member is charged, the toner on the image holding member or an external additive of the toner often adheres to the charging member, and the adhesion (surface resistance) of the surface of the charging member due to such deposits. In some cases, the charging performance may become unstable due to variations in the charging performance. For this reason, the contact charging type charging device needs to have a mechanism for cleaning the surface of the charging member, and the charging unit adopts a method of cleaning the surface of the charging member by a cleaning member that comes into contact with the rotating charging member. There are many devices.

  On the other hand, in order to prevent adhesion of toner and toner external additives, studies have been made on improving the durability of the surface layer material of the charging member.

  In Patent Document 1, a conductive elastic layer is formed on the outer periphery of a metal core in order to provide a conductive roll that can maintain an appropriate electrical resistance even when used for a long period of time and obtain a good image. A softener transition prevention layer mainly composed of N-methoxymethylated nylon is formed on the outer periphery of the body layer, a resistance adjustment layer is formed on the outer periphery of the softener transition prevention layer, and N- A protective layer mainly composed of methoxymethylated nylon is formed.

  In Patent Document 2, in order to provide a charging roll having excellent toner adhesion resistance to polymerized toner and excellent roll surface durability, a shaft, a base rubber layer formed on the outer periphery thereof, and a base rubber layer A charging roll comprising a softener transition preventing layer formed on the outer periphery, a resistance adjusting layer formed on the outer periphery of the softener transition preventing layer, and a surface layer formed on the outer periphery, wherein the surface layer is N -It is formed with the resin composition which contains a melamine-type resin in the ratio of 20-80 weight part with respect to 100 weight part of methoxymethylated nylon.

  In Patent Document 3, in order to provide a charging roll for an electrophotographic copying machine having excellent quality that is durable, has a resistance value that is stable under environmental conditions, and has no fear of pinhole leakage or photoreceptor contamination, The surface of the roll shaft is covered with a surface resin layer in which conductive particles are dispersed in a copolymer nylon resin containing at least one of 610 nylon, 11 nylon and 12 nylon as a polymerized unit. It is said that an intermediate layer made of a resin or rubber material in which conductive elastic body layers and conductive particles are dispersed is preferably interposed between the roll shaft body and the surface resin layer.

JP-A-6-264918 JP 2006-163059 A JP-A-7-64378

  The present invention is a charging member that can suppress image defects caused by cracks in the charging member even when used for a long period of time, a charging device including the charging member, a process cartridge, and an image forming apparatus.

The present invention includes a base material for charging the surface of an image carrier provided in an image forming apparatus, and an outermost layer provided on the base material and in contact with the image carrier, and the outermost layer Is a charging member containing a polyamide resin crosslinked using at least one of an epoxy resin containing an aromatic group and an isocyanate resin containing an aromatic group, and having a crosslinking degree of 90 % or more.

Further, the present invention includes a base material for charging the surface of the image carrier provided in the image forming apparatus, and an outermost layer provided on the base material and in contact with the image carrier, The outermost layer is a charging member that includes a polyamide resin crosslinked using an epoxy resin containing an aromatic group and has a crosslinking degree of 90% or more .

  Moreover, this invention is a charging device provided with the said charging member.

  The present invention is a process cartridge including an image carrier and the charging member.

  The present invention also provides an image carrier, the charging member, a latent image forming unit for forming a latent image on the surface of the image carrier, and a latent image formed on the surface of the image carrier with toner. And a developing unit that forms a toner image.

  According to claim 1 of the present invention, the outermost layer of the charging member does not contain a polyamide resin crosslinked using at least one of an epoxy resin and an isocyanate resin, and the degree of crosslinking is out of this range. In addition, it is possible to provide a charging member that can suppress image defects caused by cracks in the charging member even when used for a long period of time.

In addition , a charging member that can further suppress image defects caused by cracks in the charging member even when used for a long period of time as compared with the case where the epoxy resin and the isocyanate resin do not contain an aromatic group. Can be provided.

  According to claim 3 of the present invention, the outermost layer of the charging member does not contain a polyamide resin crosslinked using at least one of an epoxy resin and an isocyanate resin, and the degree of crosslinking is out of this range. Further, it is possible to provide a charging device that can suppress image defects caused by cracks in the charging member even when used for a long period of time.

  According to claim 4 of the present invention, the outermost layer of the charging member does not contain a polyamide resin crosslinked using at least one of an epoxy resin and an isocyanate resin, and the degree of crosslinking is out of this range. In addition, it is possible to provide a process cartridge that can suppress image defects caused by cracks in the charging member even when used for a long period of time.

  According to claim 5 of the present invention, the outermost layer of the charging member does not contain a polyamide resin crosslinked using at least one of an epoxy resin and an isocyanate resin, and the degree of crosslinking is out of this range. Thus, it is possible to provide an image forming apparatus capable of suppressing image defects caused by cracks in the charging member even when used for a long period of time.

  Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

<Charging member>
The charging member according to the present embodiment is a charging member that charges the surface of the image carrier provided in the image forming apparatus, and includes a base material, an outermost layer provided on the base material and in contact with the image carrier. including.

  The shape of the charging member according to the present embodiment is not particularly limited, and examples thereof include a roll shape, a brush shape, a belt (tube) shape, and a blade shape. Among these, a roll shape (so-called charging roll) is preferable.

  In addition, as long as the charging member includes at least a base material and an outermost layer provided on the base material, the layer configuration is not particularly limited, and the outermost layer may be provided directly on the base material. One or more intermediate layers such as a conductive elastic layer may be provided between the substrate and the outermost layer.

  In addition, the charging member according to the present embodiment is a charging roll having a layer configuration in which a conductive elastic layer and a surface layer (outermost layer) are provided in this order on the surface of a base material, and having a roll shape. It is preferable.

  Hereinafter, the base material, the conductive elastic layer, and the outermost layer will be described in more detail on the assumption that the charging member according to the present embodiment is a charging roll. Of course, the constituent materials of these layers are other shapes. This charging member can also be used in the same manner.

  The base material (conductive support) functions as an electrode and a support member for the charging roll. For example, a metal or alloy such as aluminum, copper alloy, or stainless steel; iron subjected to a plating treatment such as chromium or nickel; A material made of a conductive material such as a conductive resin can be used.

  The conductive elastic layer can be formed, for example, by dispersing a conductive agent in a rubber material. Rubber materials include isoprene rubber, chloroprene rubber, epichlorohydrin rubber, butyl rubber, polyurethane, silicone rubber, fluorine rubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber, ethylene propylene rubber, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide- Examples include allyl glycidyl ether copolymer rubber, ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile-butadiene copolymer rubber (NBR), natural rubber, and blended rubbers thereof.

  Among these, polyurethane, silicone rubber, EPDM, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, NBR, and blended rubbers thereof are preferably used. These rubber materials may be foamed or non-foamed.

  As the conductive agent, an electronic conductive agent or an ionic conductive agent is used.

  Examples of the electronic conductive agent include carbon black such as ketjen black and acetylene black; pyrolytic carbon; graphite; various conductive metals or alloys such as aluminum, copper, nickel, and stainless steel; tin oxide, indium oxide, and titanium oxide. Examples thereof include various conductive metal oxides such as tin oxide-antimony oxide solid solution and tin oxide-indium oxide solid solution; and the like.

  Examples of the ion conductive agent include perchlorates and chlorates such as tetraethylammonium and lauryltrimethylammonium; alkali metals such as lithium and magnesium, alkaline earth metal perchlorates and chlorates, and the like. Can be mentioned.

  These conductive agents may be used alone or in combination of two or more. The amount of the conductive agent added to the conductive elastic layer is not particularly limited. However, in the case of the electronic conductive agent, the range of 1 part by mass to 30 parts by mass with respect to 100 parts by mass of the rubber material. It is preferable that it is in the range of 15 parts by mass or more and 25 parts by mass or less. On the other hand, in the case of the ionic conductive agent, it is preferably in the range of 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the rubber material, and 0.5 to 3.0 parts by mass. The following range is more preferable.

  When forming the conductive elastic layer, the mixing method and mixing order of each component of the conductive agent, rubber material, and other components (such as a vulcanizing agent and a foaming agent added as necessary) constituting this layer are particularly Although not limited, as a general method, a method in which all components are mixed in advance with a tumbler, a V blender or the like, and uniformly melt-mixed with an extruder can be exemplified.

  The hardness of the conductive elastic layer is preferably in the range of 40 to 80 in Asker C. If the hardness of the conductive elastic layer is less than 40, the conductive elastic layer is easily deformed and cracks are likely to occur. If the hardness exceeds 80, the nip pressure at the contact portion with the photoreceptor increases and cracks are generated. May be easier to do.

  Next, the outermost layer will be described. In the charging member according to the present embodiment, the outermost layer includes a polyamide resin crosslinked using at least one of an epoxy resin and an isocyanate resin, and has a degree of crosslinking of 30% or more. This crosslinked polyamide resin is obtained by crosslinking a polyamide resin using at least one of an epoxy resin and an isocyanate resin.

  The conventional charging member has insufficient durability when used for a long period of time, and the charging member may be cracked. The adhesion or deposition of toner or toner external additives or the like occurs in the crack portion, thereby causing variations in the resistance (surface resistance) of the surface of the charging member, destabilizing charging performance, and causing image defects. there were. In the case of long-term use, the outermost layer of the charging member includes a polyamide resin having a specific range of cross-linking degree that is cross-linked using at least one of an epoxy resin and an isocyanate resin. In addition, it has been found that image defects caused by cracks in the charging member can be suppressed.

  The polyamide resin used for the outermost layer has good adhesion of the toner and the external additive. The polyamide resin is not particularly limited, and examples thereof include polyamide resins described in the polyamide resin handbook, Osamu Fukumoto, 8400, (Nikkan Kogyo Shimbun). Among them, the outermost layer is formed by a coating film forming method such as an immersion method. From the viewpoint of formation, solvent-soluble nylon such as alcohol-soluble nylon that is soluble in alcohol such as methanol and ethanol is preferable.

  Examples of the solvent-soluble nylon include N-alkoxyalkylated nylon obtained by alkoxyalkylating nylon such as nylon 6, nylon 11, nylon 12, nylon 6,6, nylon 6,10 and the like, nylon 6, nylon 11, nylon 12, Examples thereof include copolymer nylon which is at least two copolymers among nylon 6,6, nylon 6,10 and the like.

  The weight average molecular weight of the polyamide resin is preferably 10,000 or more and less than 100,000. If the weight average molecular weight of the polyamide resin is less than 10,000, the strength of the film may be weakened, and if it exceeds 100,000, the uniformity of the film may be reduced.

  The degree of crosslinking of the polyamide resin crosslinked using at least one of the epoxy resin and the isocyanate resin is 30% or more, preferably 60% or more, and more preferably 90% or more. When the degree of crosslinking is less than 30%, the durability of the charging member is reduced, and image defects due to cracks in the charging member are generated.

  This outermost layer can be formed, for example, by reacting a polyamide resin such as a solvent-soluble nylon such as alcohol-soluble nylon with an epoxy resin or an isocyanate resin to perform three-dimensional crosslinking. Thereby, the durability of the charging member is remarkably improved, and there is almost no image defect due to the crack of the charging member, and it can be used for a long time.

  N-methoxymethylated nylon, which is one of alcohol-soluble nylons, has only a methoxymethylated portion at the crosslinking point, and methoxymethylation of amide groups is about 20% to 30% in all amide groups in the reaction. However, there is a limit to further increasing the degree of crosslinking. In addition, cross-linking with melamine groups makes the surface layer brittle and lowers durability.

  However, the epoxy groups and isocyanate groups of epoxy resins and isocyanate resins can react with almost all amide groups of polyamide resins such as nylon, and the crosslink density is greatly increased, so the durability is dramatically increased. improves. Furthermore, it is preferable that an epoxy resin or an isocyanate resin contains an aromatic group. Epoxy resins and isocyanate resins with aromatic groups inside are effective in improving bleed blockability from the underlying conductive elastic layer due to the structure of the aromatic groups, and have been difficult to crack. And bleed block properties can be achieved.

  Examples of the isocyanate resin used as a crosslinking agent for crosslinking with the polyamide resin include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, Examples include isocyanate, tetramethylxylene diisocyanate, lysine ester tosiisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, norbornene diisocyanate, and prepolymerized ones may be used. An isocyanate may be used individually by 1 type and may use multiple types together.

  The epoxy resin used as a cross-linking agent for cross-linking with the polyamide resin refers to monomers, oligomers and polymers generally having two or more epoxy groups in one molecule, and the molecular weight and molecular structure thereof are not particularly limited. , Biphenyl type epoxy resin, bisphenol type epoxy resin, stilbene type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, triphenolmethane type epoxy resin, alkyl-modified triphenolmethane type epoxy resin, triazine nucleus-containing epoxy resin, Examples include dicyclopentadiene-modified phenol type epoxy resin, phenol aralkyl type epoxy resin (having a phenylene skeleton, diphenylene skeleton, etc.), and these may be used alone or in combination of two or more. Good.

  Among these, biphenyl type epoxy resin, bisphenol type epoxy resin, stilbene type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, triphenolmethane type epoxy resin are preferable, biphenyl type epoxy resin, bisphenol type epoxy resin, Phenol novolac type epoxy resins and cresol novolac type epoxy resins are more preferred, and bisphenol type epoxy resins are particularly preferred.

  An epoxy resin curing agent may be used to accelerate the curing of the epoxy resin. Any epoxy resin curing agent known to those skilled in the art can be used. For example, straight chain aliphatic diamine having 2 to 20 carbon atoms, such as ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, metaphenylenediamine, paraphenylenediamine, paraxylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylsulfone, 4,4′-diaminodicyclohexane, bis (4-aminophenyl) phenylmethane, 1,5-diamino Amino acids such as naphthalene, meta-xylene diamine, para-xylene diamine, 1,1-bis (4-aminophenyl) cyclohexane, dicyanodiamide, resol-type phenols such as aniline-modified resole resin and dimethyl ether resole resin Resin, phenol novolac resin, cresol novolac resin, tert-butylphenol novolak resin, novolac type phenol resin such as nonylphenol novolac resin, polyoxystyrene such as polyparaoxystyrene, phenol resin such as phenol aralkyl resin, acid anhydride, etc. Although illustrated, it is not particularly limited thereto.

  Among these, resol type phenol resins such as aniline-modified resole resin and dimethyl ether resole resin, phenol novolac resin, cresol novolac resin, tert-butylphenol novolac resin, novolac type phenol resin such as nonylphenol novolac resin, and polyoxy such as polyparaoxystyrene Phenol resins such as styrene and phenol aralkyl resins are preferred, novolac type phenol resins and phenol aralkyl resins are more preferred, and phenol aralkyl resins are particularly preferred.

  The film thickness of the outermost layer should be thick considering the durability due to wear as a charging member, but if it is too thick, the charging ability to the image carrier deteriorates, so the range is from 0.01 μm to 1,000 μm. Preferably, the range of 0.1 μm to 500 μm is more preferable, and the range of 0.5 μm to 100 μm is more preferable. As the outermost layer production method, the outermost layer is formed by a dipping method, a spray method, a vacuum deposition method, a plasma forming method, or the like on a substrate or a substrate on which an intermediate layer is formed. In this respect, the dipping method is preferable.

  The outermost layer preferably contains a conductive material, and more preferably contains conductive particles. As the conductive particles, carbon black or tin oxide is preferable.

<Cleaning member>
The cleaning member as a cleaning member for cleaning the outer surface of the charging member includes a core material and an elastic layer provided on the outer peripheral surface of the core material, and the elastic layer is preferably formed of a foam. Furthermore, you may have the application layer which apply | coated the elastic layer. Moreover, you may provide the intermediate | middle layer and elastic layer which used the hot-melt-adhesive etc. between the core material and the elastic layer as needed.

  By using the foam coated with the surface, the advantages of using contact charging means, especially the charging roller, are maintained, and the contamination of the charging roller due to adhesion of toner, paper dust and other foreign matters, and the resulting image flow In addition to avoiding image defects such as image blurring, imparting conductivity to the cleaning member and maintaining a good charging function without causing distortion during nip, as well as damaging the charging roller and photoconductor Can be prevented.

  The shape of the cleaning member according to the present embodiment is not particularly limited, and examples thereof include a roll shape, a brush shape, and a blade shape. Among these, a roll shape (so-called cleaning roll) that applies less stress to the charging member is preferable. However, if the charging member according to this embodiment is used, a blade-shaped cleaning member that is stressed by the charging member is used. Even in the case of long-term use, image defects caused by cracks in the charging member can be suppressed, and the cost of the cleaning member can be reduced.

  The hardness of the cleaning member is preferably in the range of 100N to 500N. If the hardness of the cleaning member is less than 100N, the cleaning property may be insufficient, and if it exceeds 500N, the surface of the charging member may be damaged.

  The hardness of the cleaning member is measured as follows. In accordance with JIS K6400 (1997) A method, the hardness is the original thickness when a load of 4.9 N is applied using a φ200 mm pressure plate to a sample of 50 mm × 390 mm × 390 mm, and then 75% before using a pressure plate. After compression, the load is immediately removed, and the load (N) 20 seconds after 25% compression is again measured as the hardness.

  Next, each member of the cleaning member will be described.

  The core material will be described. As the core material, generally, a molded article such as iron, copper, brass, stainless steel, aluminum, nickel is used. As the core material, a resin molded product in which other conductive particles are dispersed can be used.

  As the elastic material constituting the elastic layer, any material can be used as long as desired characteristics can be obtained. For example, polyurethane resin, polystyrene resin, polyethylene, polypropylene resin, nylon resin, melamine resin, polyethylene terephthalate resin, ethylene-vinyl acetate copolymer, butyl rubber, nitrile rubber, polyisoprene rubber, polybutadiene rubber, silicone rubber, natural rubber, ethylene Examples thereof include foams such as propylene rubber, ethylene-propylene-diene rubber, styrene-butadiene rubber, acrylic rubber, and chloroprene rubber. Of these, polyurethane foam is particularly preferably used.

  The polyurethane foam constituting the elastic layer is obtained using at least a polyol, a foam stabilizer, and a reaction catalyst.

  As the polyol, polyoxypropylene glycol, polyoxytetramethylene glycol, polyester polyol, polycaprolactone polyol, polycarbonate polyol and the like can be used. These polyols may be used alone or in admixture of two or more.

  Also, isocyanates can be used to crosslink with polyols. Isocyanates include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, triisocyanate, tetramethylxylene diisocyanate, lysine ester tosiisocyanate. Lysine diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, norbornene diisocyanate and the like can be used. Isocyanate may be used alone or in combination of two or more.

  Examples of the reaction catalyst include triethylamine, tetramethylethylenediamine, triethylenediamine (TEDA), bis (N, N-dimethylamino-2-ethyl) ether, N, N, N ′, N′-tetramethylhexamethylenediamine, Examples include amine catalysts such as bis (2-dimethylaminoethyl) ether (TOYOCAT-ET, manufactured by Tosoh Corporation), carboxylic acid metal salts such as potassium acetate and potassium octylate, and organometallic compounds such as dibutyltin dilaurate. . Among these, the use of an amine-based catalyst is preferable because it is suitable for the production of water-foamed polyurethane foam. These reaction catalysts may be used alone or in combination of two or more.

  Examples of the foam stabilizer include silicone surfactants such as dimethyl silicone oil and polyether-modified silicone oil, cationic surfactants, anionic surfactants, and amphoteric surfactants.

  The amount of the catalyst used is preferably in the range of 0.01% by mass to 5% by mass, more preferably in the range of 0.05% by mass to 3% by mass, based on the total amount of polyol and isocyanate. The range of 1 mass% or more and 1 mass% or less is more preferable. When no catalyst is used, unreacted polymer may remain on the cleaning roll, and image defects may occur due to bleeding at the contact portion with the charging member.

  Next, other blends will be described. Examples of other blends include a conductive agent. Examples of the conductive agent include carbon conductive agents such as ketjen black, acetylene black, oil furnace black, and thermal black, and ionic conductive agents such as ammonium compounds such as tetraethylammonium and stearyltrimethylammonium chloride. .

  Examples of other blends include additives such as flame retardants, deterioration inhibitors, and plasticizers. In addition, these other compounds may be used alone or in combination. These additives may be used alone or in combination.

  In the present embodiment, it is preferable that the number of foam cells (cells / 25 mm) is in the range of 20 or more and 200 or less as the form of the foam. When the number is less than 20 or more than 200, the charging member cleaning performance may not be satisfied.

<Manufacturing method of cleaning member>
A method for producing a polyurethane foam will be described. There is no restriction | limiting in particular about the manufacturing method of a polyurethane foam, Although what is necessary is just based on a conventional method, if the example is shown, it will be as follows. First, a polyurethane foam can be obtained by mixing a polyurethane polyol, a foam stabilizer, a catalyst, and a conductive agent, if necessary, as raw materials, followed by heating and reaction curing.

  The temperature and time for mixing the raw materials are not particularly limited, but the mixing temperature is usually in the range of 10 to 90 ° C., preferably in the range of 20 to 60 ° C. The mixing time is usually about 10 seconds to 20 minutes, preferably about 30 seconds to 5 minutes. Moreover, when making it heat-react and cure, a polyurethane foam can be obtained by making it foam by a conventionally well-known method.

  Here, there is no restriction | limiting in particular about the foaming method, Any methods, such as the method of using a foaming agent and the method of mixing bubbles by mechanical stirring, can be used.

  Next, a method for manufacturing the cleaning member will be described. As a manufacturing method of the cleaning roll, for example, a raw material is injected into a mold and foamed, and a polyurethane foam having a desired shape is coated on a core material. A polyurethane foam is slab-molded to obtain a desired shape. Examples of the method include a method of coating the core material after processing by grinding or the like.

<Charging device>
FIG. 1 is a schematic configuration diagram illustrating an example of a charging device according to the present embodiment. The charging device 21 includes a charging roll 12 for charging a member to be charged (for example, an image carrier) and a cleaning roll 10 disposed in contact with the outer peripheral surface of the charging roll 12. As the charging roll 12, a charging roll having the outermost layer 14 is applied.

  The cleaning roll 10 contacts the outer peripheral surface (elastic layer surface) of the cleaning roll 10 with the outermost layer 14 of the charging roll 12 in a detachable state. Further, the charging roll 12 may be installed so as to be reciprocally movable in the axial direction. Accordingly, when cleaning is not necessary (for example, when the image forming apparatus is stopped for a long time), the cleaning roll 10 can be placed away from the charging roll 12 and the surface of the charging roll 12 is substantially uniform. Can be cleaned.

  When the cleaning roll 10 is in contact with the charging roll 12, the cleaning roll 10 is arranged in a state of being pressed against the charging roll 12, and is driven to rotate as the charging roll 12 rotates. Thereby, generation | occurrence | production of the scratches to the charging roll 12 can be prevented.

  In the charging device 21, a member to be charged (for example, an image carrier) can be charged by the charging roll 12 while cleaning the surface of the charging roll 12 by the cleaning roll 10.

  By applying the above-described charging roll, it is possible to suppress image defects caused by a charging roll crack or the like even in the case of long-term use. Further, since the durability of the surface of the charging roll 12 is high and the pressing force of the cleaning roll 10 to the charging roll 12 can be increased, the charging roll 12 can be cleaned more satisfactorily.

<Image forming apparatus and process cartridge>
FIG. 2 is a schematic diagram illustrating an example of an image forming apparatus according to the present embodiment. An image forming apparatus 100 shown in FIG. 2 includes, in an image forming apparatus main body (not shown), a process cartridge 20 including at least a charging device 21, an exposure device 30 as a latent image forming unit, and a transfer device 40 as a transfer unit. And an intermediate transfer member 50. In the image forming apparatus 100, the exposure device 30 is disposed at a position where the electrophotographic photosensitive member 1 (image holding member) can be exposed from the opening of the process cartridge 20, and the transfer device 40 is interposed via the intermediate transfer member 50. The intermediate transfer member 50 is disposed at a position where a part of the intermediate transfer member 50 is in contact with the electrophotographic photosensitive member 1.

  The process cartridge 20 has a case in which the electrophotographic photosensitive member 1, a developing device 25 as a developing means, a cleaning device 27, and a fibrous member (flat brush shape) 29 are combined with a charging device 21 and combined with an attachment rail in a case. It is. The case is provided with an opening for exposure.

  The charging device is applied as the charging device 21. The charging device 21 includes the charging roll 12 and the cleaning roll 10 as described above.

  Here, the cleaning roll 10 is preferably disposed in contact with the charging roll 12 under the following conditions. As shown in FIG. 11, in a cross section orthogonal to each axis of the charging roll 12, the cleaning roll 10, and the electrophotographic photosensitive member 1, a line passing through the axis of the charging roll 12 and parallel to the direction of gravity (in FIG. 11). Of the positions where the dotted line) and the outer periphery of the charging roll 12 intersect, the position above the axis of the charging roll 12 in the direction of gravity is α, and the contact position between the charging roll 12 and the electrophotographic photosensitive member 1 is β. In this case, the cleaning roll 10 is sandwiched between the position α and the position β on the side where the electrophotographic photosensitive member 1 is disposed with respect to the contact point γ between the cleaning roll 10 and the charging roll 12 with respect to the axial point of the charging roll 12. The charging roll 12 is preferably disposed so as to be located outside the outer periphery T of the charging roll 12.

  By disposing the cleaning roll 10 in this way, it is possible to prevent foreign matters that have fallen off the cleaning roll 10 from falling onto the charging roll 12 and the electrophotographic photosensitive member 1. For this reason, since the charging failure to the electrophotographic photosensitive member 1 due to the foreign matter is suppressed, the generation of color points in the image quality can be prevented, and the image quality failure can be prevented over a long period of time.

  Next, the electrophotographic photoreceptor 1 will be described. FIG. 6 is a schematic cross-sectional view showing an example of an electrophotographic photosensitive member used in the image forming apparatus according to the present embodiment. An electrophotographic photosensitive member 1 shown in FIG. 6 includes a conductive support 2 and a photosensitive layer 3. The photosensitive layer 3 has a structure in which an undercoat layer 4, a charge generation layer 5, a charge transport layer 6 and a protective layer 7 are laminated in this order on a conductive support 2.

  7 to 10 are schematic cross-sectional views illustrating other examples of the electrophotographic photosensitive member. The electrophotographic photosensitive member shown in FIGS. 7 and 8 includes the photosensitive layer 3 in which the functions are separated into the charge generating layer 5 and the charge transporting layer 6 as in the electrophotographic photosensitive member shown in FIG. In FIGS. 9 and 10, the charge generation material and the charge transport material are contained in the same layer (single-layer type photosensitive layer 8).

  The electrophotographic photoreceptor 1 shown in FIG. 7 has a structure in which a charge generation layer 5, a charge transport layer 6 and a protective layer 7 are sequentially laminated on a conductive support 2. The electrophotographic photoreceptor 1 shown in FIG. 8 has a structure in which an undercoat layer 4, a charge transport layer 6, a charge generation layer 5, and a protective layer 7 are sequentially laminated on a conductive support 2.

  The electrophotographic photoreceptor 1 shown in FIG. 9 has a structure in which an undercoat layer 4, a single-layer type photosensitive layer 8, and a protective layer 7 are sequentially laminated on a conductive support 2. Further, the electrophotographic photoreceptor 1 shown in FIG. 10 has a structure in which a single-layer type photosensitive layer 8 and a protective layer 7 are sequentially laminated on a conductive support 2.

  In the electrophotographic photosensitive member shown in FIGS. 6 to 10, the undercoat layer 4 is not necessarily provided.

  The photosensitive layer provided in the electrophotographic photosensitive member 1 includes a single layer type photosensitive layer containing a charge generation material and a charge transport material in the same layer, or a layer containing a charge generation material (charge generation layer) and a charge transport material. Any of the function-separated type photosensitive layers provided separately with the contained layer (charge transport layer) may be used. In the case of the function-separated type photosensitive layer, the order of stacking the charge generation layer and the charge transport layer may be the upper layer. In the case of a function-separated photosensitive layer, it is possible to achieve functional separation because it is possible to perform functional separation in which each layer only has to satisfy each function.

  The electrophotographic photosensitive member 1 is not particularly limited, and known ones can be applied. Hereinafter, each element will be described based on the electrophotographic photosensitive member 1 shown in FIG. 6 as a representative example.

  Examples of the conductive support 2 include a metal plate, a metal drum, and a metal belt formed using a metal or an alloy such as aluminum, copper, zinc, stainless steel, chromium, nickel, molybdenum, vanadium, indium, gold, or platinum. Etc. Further, as the conductive support 2, paper, plastic film, belt or the like coated, vapor-deposited or laminated with a conductive polymer, a conductive compound such as indium oxide, or a metal or alloy such as aluminum, palladium, or gold can be used.

  The surface of the conductive support 2 is desirably roughened to a centerline average roughness (Ra) of 0.04 μm or more and 0.5 μm or less in order to prevent interference fringes generated when laser light is irradiated. . When the center line average roughness (Ra) of the surface of the conductive support 2 is less than 0.04 μm, the effect of preventing interference tends to be insufficient because it is close to a mirror surface. On the other hand, if the center line average roughness (Ra) exceeds 0.5 μm, the image quality tends to be insufficient even if a film is formed. When non-interfering light is used as a light source, it is not particularly necessary to roughen the interference fringes, and it is possible to prevent the occurrence of defects due to irregularities on the surface of the conductive support 2, which is suitable for longer life.

  Surface roughening methods include wet honing by suspending an abrasive in water and spraying it on the support, or centerless grinding, in which the support is pressed against a rotating grindstone, and grinding is performed continuously, anodization Processing is desirable.

  As another roughening method, a conductive or semi-conductive powder is dispersed in a resin without roughening the surface of the conductive support 2, and a layer is formed on the support surface. A method of roughening with particles formed and dispersed in the layer is also preferably used.

  The anodizing treatment is to form an oxide film on the aluminum surface by anodizing in an electrolyte solution using aluminum as an anode. Examples of the electrolyte solution include a sulfuric acid solution and an oxalic acid solution. However, the intact porous anodic oxide film is chemically active, easily contaminated, and has a large resistance fluctuation due to the environment. Therefore, the pores in the anodic oxide film are sealed with pressurized water vapor or boiling water (metal salts such as nickel may be added) by volume expansion due to the hydration reaction, and a sealing process is performed to change to a more stable hydrated oxide. May be.

  The thickness of the anodic oxide film is desirably 0.3 μm or more and 15 μm or less. When this film thickness is less than 0.3 μm, the barrier property against implantation tends to be poor and the effect tends to be insufficient. On the other hand, when it exceeds 15 μm, there is a tendency that the residual potential increases due to repeated use.

  Further, the conductive support 2 may be subjected to treatment with an acidic aqueous solution or boehmite treatment. The treatment with an acidic treatment solution composed of phosphoric acid, chromic acid and hydrofluoric acid is carried out as follows. First, an acidic treatment liquid is adjusted. The mixing ratio of phosphoric acid, chromic acid and hydrofluoric acid in the acidic treatment liquid is such that phosphoric acid is in the range of 10% by mass to 11% by mass, chromic acid is in the range of 3% by mass to 5% by mass, and hydrofluoric acid is 0.00%. The concentration of these acids is preferably in the range of 13.5 mass% to 18 mass%. The treatment temperature is preferably 42 ° C. or more and 48 ° C. or less, but by keeping the treatment temperature high, a thicker film can be formed faster. The film thickness is preferably from 0.3 μm to 15 μm. If it is less than 0.3 μm, the barrier property against injection tends to be poor and the effect tends to be insufficient. On the other hand, when it exceeds 15 μm, there is a tendency that the residual potential increases due to repeated use.

  The boehmite treatment is performed, for example, by immersing in pure water of 90 ° C. or more and 100 ° C. or less for 5 minutes or more and 60 minutes or less, or by contacting with heated steam of 90 ° C. or more and 120 ° C. or less for 5 minutes or more and 60 minutes or less Can do. The film thickness is preferably 0.1 μm or more and 5 μm or less. This may be further anodized using an electrolyte solution with low film solubility such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, citrate, etc. Good.

  The undercoat layer 4 is formed on the conductive support 2. The undercoat layer 4 includes, for example, at least one of an organometallic compound and a binder resin.

  As organometallic compounds, zirconium chelate compounds, zirconium alkoxide compounds, organic zirconium compounds such as zirconium coupling agents, titanium chelate compounds, titanium alkoxide compounds, organotitanium compounds such as titanate coupling agents, aluminum chelate compounds, aluminum coupling agents In addition to organoaluminum compounds such as antimony alkoxide compounds, germanium alkoxide compounds, indium alkoxide compounds, indium chelate compounds, manganese alkoxide compounds, manganese chelate compounds, tin alkoxide compounds, tin chelate compounds, aluminum silicon alkoxide compounds, aluminum titanium alkoxide compounds, And aluminum zirconium alkoxide compounds. .

  As the organometallic compound, an organic zirconium compound, an organic titanyl compound, and an organoaluminum compound are particularly preferably used because of low residual potential and good electrophotographic characteristics.

  As the binder resin, polyvinyl alcohol, polyvinyl methyl ether, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, polyamide, polyimide, casein, gelatin, polyethylene, polyester, phenol resin, Examples include known vinyl chloride-vinyl acetate copolymers, epoxy resins, polyvinyl pyrrolidone, polyvinyl pyridine, polyurethane, polyglutamic acid, polyacrylic acid, and the like. When these are used in combination of two or more, the mixing ratio can be appropriately set as necessary.

  The undercoat layer 4 includes vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris-2-methoxyethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloxypropyl. Trimethoxysilane, γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-2-aminoethylaminopropyltrimethoxysilane, γ-mercapropropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, β A silane coupling agent such as −3,4-epoxycyclohexyltrimethoxysilane may be contained.

  Further, in the undercoat layer 4, an electron transporting pigment can be mixed and dispersed from the viewpoint of low residual potential and environmental stability. Examples of the electron transport pigment include organic pigments such as perylene pigment, bisbenzimidazole perylene pigment, polycyclic quinone pigment, indigo pigment, and quinacridone pigment described in JP-A-47-30330, cyano group, nitro group, Examples thereof include organic pigments such as bisazo pigments and phthalocyanine pigments having electron-withdrawing substituents such as nitroso groups and halogen atoms, and inorganic pigments such as zinc oxide and titanium oxide.

  Among these pigments, perylene pigments, bisbenzimidazole perylene pigments, polycyclic quinone pigments, zinc oxide or titanium oxide are preferably used because of their high electron mobility.

  In addition, the surface of these pigments may be surface-treated with the above coupling agent or binder resin for the purpose of controlling dispersibility and charge transporting property.

  If the amount of the electron transporting pigment is too large, the strength of the undercoat layer 4 is lowered and causes coating film defects. Therefore, the amount is preferably 95% by mass or less, more preferably 90% by mass based on the total solid content of the undercoat layer 4. % Used.

  Also, it is desirable to add various organic compound powders or inorganic compound powders to the undercoat layer 4 for the purpose of improving electrical characteristics and light scattering properties. In particular, white pigments such as titanium oxide, zinc oxide, zinc white, zinc sulfide, lead white, lithopone, and inorganic pigments such as alumina, calcium carbonate, barium sulfate, polytetrafluoroethylene resin particles, benzoguanamine resin particles, Styrene resin particles and the like are effective.

  The additive powder preferably has a volume average particle diameter of 0.01 μm or more and 2 μm or less. The powder is added as necessary, but the addition amount is preferably 10% by mass or more and 90% by mass or less, and 30% by mass or more and 80% by mass or less, based on the total solid content of the undercoat layer 4. More preferably.

  The undercoat layer 4 is formed using an undercoat layer forming coating solution containing the above-described constituent materials. The organic solvent used in the coating solution for forming the undercoat layer is one that dissolves an organometallic compound or a binder resin and does not cause gelation or aggregation when an electron transporting pigment is mixed and / or dispersed. If it is.

  Examples of the organic solvent include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, and methylene chloride. , Chloroform, chlorobenzene, toluene and the like. These can be used individually by 1 type or in mixture of 2 or more types.

  Conventional methods using a ball mill, a roll mill, a sand mill, an attritor, a vibrating ball mill, a colloid mill, a paint shaker ultrasonic wave, etc. are applied as a method of mixing and / or dispersing each constituent material. Mixing and / or dispersion is performed in an organic solvent.

  As a coating method for forming the undercoat layer 4, usual methods such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method are used. be able to.

  The drying is usually performed at a temperature at which the solvent can be evaporated and a film can be formed. In particular, the conductive support 2 subjected to the acidic solution treatment and the boehmite treatment is preferably formed with the undercoat layer 4 because the defect concealing power of the substrate tends to be insufficient.

  The thickness of the undercoat layer 4 is desirably 0.01 μm or more and 30 μm or less, and more desirably 0.05 μm or more and 25 μm or less.

  The charge generation layer 5 includes a charge generation material and, if necessary, a binder resin.

  Known charge generation materials include azo pigments such as bisazo and trisazo, condensed aromatic pigments such as dibromoanthanthrone, organic pigments such as perylene pigments, pyrrolopyrrole pigments and phthalocyanine pigments, and inorganic pigments such as trigonal selenium and zinc oxide. Can be used. As the charge generation material, metal and metal-free phthalocyanine pigments, trigonal selenium, dibromoanthanthrone and the like are particularly desirable when a light source having an exposure wavelength of 380 nm to 500 nm is used. Among them, hydroxygallium phthalocyanine disclosed in JP-A-5-263007 and JP-A-5-279591, chlorogallium phthalocyanine disclosed in JP-A-5-98181, JP-A-5-140472 and special Dichlorotin phthalocyanine disclosed in Kaihei 5-140473 and titanyl phthalocyanine disclosed in JP-A-4-189873 and JP-A-5-43813 are particularly desirable.

Further, among the above hydroxygallium phthalocyanines, in the spectral absorption spectrum, it has an absorption maximum at 810 nm or more and 839 nm or less, the primary particle diameter is 0.10 μm or less, and the specific surface area value by BET method is 45 m ² / What is more than g is desirable.

  The binder resin can be selected from a wide range of insulating resins, and can also be selected from organic photoconductive polymers such as poly-N-vinyl carbazole, polyvinyl anthracene, polyvinyl pyrene, and polysilane. Desirable binder resins include polyvinyl butyral resin, polyarylate resin (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin. Insulating resins such as polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin can be mentioned, but are not limited thereto. These binder resins can be used singly or in combination of two or more.

  The charge generation layer 5 is formed by vapor deposition of a charge generation material or a coating solution for forming a charge generation layer containing a charge generation material and a binder resin. When the charge generation layer 5 is formed using a charge generation layer forming coating solution, the blending ratio (mass ratio) of the charge generation material and the binder resin is preferably in the range of 10: 1 to 1:10.

  As a method for dispersing each of the constituent materials in the charge generation layer forming coating solution, a usual method such as a ball mill dispersion method, an attritor dispersion method, a sand mill dispersion method, or the like can be used. At this time, a condition that the crystal form of the pigment is not changed by the dispersion is required. Further, in this dispersion, it is effective to make the particles preferably have a particle size of 0.5 μm or less, more preferably 0.3 μm or less, and even more preferably 0.15 μm or less.

  Solvents used for dispersion include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, and methylene chloride. Ordinary organic solvents such as chloroform, chlorobenzene and toluene. These can be used individually by 1 type or in mixture of 2 or more types.

  When the charge generation layer 5 is formed using the charge generation layer forming coating solution, the coating method includes blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating. Ordinary methods such as a coating method and a curtain coating method can be used.

  The film thickness of the charge generation layer 5 is desirably 0.1 μm or more and 5 μm or less, and more desirably 0.2 μm or more and 2.0 μm or less.

  The charge transport layer 6 includes a charge transport material and a binder resin, or a polymer charge transport material.

  Charge transport materials include quinone compounds such as p-benzoquinone, chloranil, bromanyl, anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, xanthone compounds, benzophenone compounds , Electron transport compounds such as cyanovinyl compounds and ethylene compounds, triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds, etc. Examples thereof include, but are not limited to, hole transporting compounds. These charge transport materials can be used singly or in combination of two or more.

  Moreover, as a charge transport material, the compound shown by the following general formula (a-1), (a-2) or (a-3) from a mobility viewpoint is desirable.

In the above formula (a-1), R ¹⁶ represents a hydrogen atom or a methyl group, and n10 represents 1 or 2. Ar ₆ and Ar ₇ are each independently a substituted or unsubstituted aryl group, —C ₆ H ₄ —C (R ³⁸ ) ═C (R ³⁹ ) (R ⁴⁰ ), or —C ₆ H ₄ —CH. ═CH—CH═C (Ar) ₂ is substituted with a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl group having 1 to 3 carbon atoms. And substituted amino groups. R ³⁸ , R ³⁹ and R ⁴⁰ represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and Ar represents a substituted or unsubstituted aryl group.

In the above formula (a-2), R ¹⁷ and R ^{17 ′} each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms, R ¹⁸ , R ^{18 ′} , R ¹⁹ and R ^{19 ′} are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an amino group substituted with an alkyl group having 1 to 2 carbon atoms, substituted or unsubstituted A substituted aryl group, —C (R ³⁸ ) ═C (R ³⁹ ) (R ⁴⁰ ), or —CH═CH—CH═C (Ar) ₂ , wherein R ³⁸ , R ³⁹ and R ⁴⁰ are each independently A hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, Ar represents a substituted or unsubstituted aryl group. N2 and n3 each independently represents an integer of 0 to 2.

In the above formula (a-3), R ₂₁ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a substituted or unsubstituted aryl group, or —CH═CH—CH═. C (Ar) ₂ is shown. Ar represents a substituted or unsubstituted aryl group. R ₂₂ and R ₂₃ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an amino group substituted with an alkyl group having 1 to 2 carbon atoms, or A substituted or unsubstituted aryl group is shown.

  Examples of the binder resin used for the charge transport layer 6 include polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, and vinylidene chloride. -Acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, and the like. These binder resins can be used singly or in combination of two or more. The blending ratio (mass ratio) between the charge transport material and the binder resin is preferably 10: 1 or more and 1: 5 or less.

  As the polymer charge transporting material, known materials having charge transporting properties such as poly-N-vinylcarbazole and polysilane can be used. In particular, polyester polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 have a high charge transport property and are particularly desirable.

  Although the polymer charge transport material alone can be used as a constituent material of the charge transport layer 6, it may be mixed with the binder resin to form a film.

  The charge transport layer 6 is formed using a charge transport layer forming coating solution containing the above-described constituent materials. Examples of the solvent for the coating solution for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, ketones such as acetone and 2-butanone, and halogenated fats such as methylene chloride, chloroform and ethylene chloride. Examples thereof include ordinary organic solvents such as aromatic hydrocarbons, cyclic ethers such as tetrahydrofuran and ethyl ether, and linear ethers. These may be used alone or in combination of two or more.

  As a coating method of the coating solution for forming the charge transport layer, a usual method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method should be used. Can do.

  The film thickness of the charge transport layer 6 is desirably 5 μm or more and 50 μm or less, and more desirably 10 μm or more and 30 μm or less.

  The photosensitive layer 3 contains additives such as an antioxidant, a light stabilizer, and a heat stabilizer for the purpose of preventing deterioration of the photoreceptor due to ozone, oxidizing gas, or light and heat generated in the image forming apparatus. Can be added.

  Examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds. Examples of the light stabilizer include derivatives such as benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine.

  The photosensitive layer 3 can contain at least one electron accepting substance for the purpose of improving sensitivity, reducing residual potential, reducing fatigue during repeated use, and the like.

Examples of the electron acceptor include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene. , Chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, phthalic acid and the like. Of these, fluorenone-based, quinone-based, and benzene derivatives having electron-withdrawing substituents such as Cl, CN, NO ₂ are particularly desirable.

  The protective layer 7 can be comprised with the following resin, for example. Examples of the resin include polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride. -Vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole, polysilane, Polymer charge transport materials such as polyester polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 can also be used. Of these, thermosetting resins such as phenol resins, thermosetting acrylic resins, thermosetting silicone resins, epoxy resins, melamine resins, urethane resins, polyimide resins, and polybenzimidazole resins are desirable. Of these, phenol resin, melamine resin, benzoguanamine resin, siloxane resin, and urethane resin are preferably used, and at the same time in the step of drying the solvent after applying a coating solution containing these resins or their precursors as the main component. Heat treatment is performed to cure and form an insoluble cured film.

  Examples of the phenolic resin include monomethylolphenols, monomers of dimethylolphenols or trimethylolphenols, mixtures thereof, oligomers thereof, or mixtures of these monomers and oligomers. Such phenol resins include resorcin, bisphenol, substituted phenols containing one hydroxyl group such as phenol, cresol, xylenol, paraalkylphenol, paraphenylphenol, and substituted phenols containing two hydroxyl groups such as catechol, resorcinol, hydroquinone, etc. It is obtained by reacting a compound having a phenol structure such as bisphenols such as bisphenol A and bisphenol Z and biphenols with formaldehyde, paraformaldehyde and the like in the presence of an acid catalyst or an alkali catalyst. As a phenol resin, what is generally marketed as a phenol resin can be used. Moreover, as a phenol resin, a resol type phenol resin is desirable. In the present specification, a relatively large molecule in which the number of repeating molecular structural units is about 2 or more and 20 or less is called an oligomer, and a molecule smaller than that is called a monomer.

As the acid catalyst, sulfuric acid, paratoluenesulfonic acid, phosphoric acid and the like are used. As the alkali catalyst, hydroxides or amine catalysts of alkali metals and alkaline earth metals such as NaOH, KOH, Ca (OH) ₂ and Ba (OH) ₂ are used.

  Examples of the amine catalyst include, but are not limited to, ammonia, hexamethylenetetramine, trimethylamine, triethylamine, and triethanolamine. When a basic catalyst is used, the carrier is remarkably trapped by the remaining catalyst, and the electrophotographic characteristics tend to be deteriorated. Therefore, it is desirable to inactivate or remove by neutralizing with an acid, or contacting with an adsorbent such as silica gel, an ion exchange resin or the like.

  As the melamine resin and the benzoguanamine resin, various types such as a methylol type in which the methylol group is intact, a full ether type in which all the methylol groups are alkyl etherified, a fluino type, a mixed type of methylol and imino groups can be used. Among these, the ether type is desirable from the viewpoint of the stability of the coating solution.

  As the urethane resin, polyfunctional isocyanate, isocyanurate, or blocked isocyanate obtained by blocking these with alcohol or ketone can be used. Among these, from the viewpoint of the stability of the coating solution, blocked isocyanate or isocyanurate is preferable, and these are desirable because they are heat-crosslinked with the additive for an electrophotographic photoreceptor used in the image forming apparatus of the present embodiment.

  As the silicone resin, a resin derived from a compound represented by the following general formula (X) can be used.

  These resins can be used alone or in admixture of two or more.

  Conductive particles may be added to the protective layer 7 in order to lower the residual potential. Examples of the conductive particles include metals, metal oxides, and carbon black. Of these, metals or metal oxides are more desirable. Examples of the metal include aluminum, zinc, copper, chromium, nickel, silver and stainless steel, or those obtained by depositing these metals on the surface of plastic particles. Examples of metal oxides include zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, indium oxide doped with tin, tin oxide doped with antimony and tantalum, and zirconium oxide doped with antimony. It is done. These can be used alone or in combination of two or more. When two or more types are used in combination, they may be simply mixed, or may be in the form of a solid solution or fusion. From the viewpoint of the transparency of the protective layer 7, the average particle size of the conductive particles is preferably 0.3 μm or less, and particularly preferably 0.1 μm or less.

  In addition, a compound represented by the following general formula (X) is added to the curable resin composition for forming the protective layer 7 in order to control various physical properties such as strength and film resistance of the protective layer 7. You can also.

Si (R ⁵⁰ ) _(4-c) Q _c (X)
(In the above formula (X), R ⁵⁰ represents a hydrogen atom, an alkyl group or a substituted or unsubstituted aryl group, Q represents a hydrolyzable group, and c represents an integer of 1 to 4.)

  Specific examples of the compound represented by the general formula (X) include the following silane coupling agents. Examples of silane coupling agents include tetrafunctional silanes such as tetramethoxysilane and tetraethoxysilane (c = 4); methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, methyltrimethoxyethoxysilane, vinyltri Methoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxy Silane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltriethoxysilane, (tridecafluoro-1,1,2,2-tetrahydrosilane Octyl) triethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, 3- (heptafluoroisopropoxy) propyltriethoxysilane, 1H, 1H, 2H, 2H-perfluoroalkyltriethoxysilane, 1H , 1H, 2H, 2H-perfluorodecyltriethoxysilane, trifunctional alkoxysilanes such as 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (c = 3); dimethyldimethoxysilane, diphenyldimethoxysilane, methyl And bifunctional alkoxysilanes such as phenyldimethoxysilane (c = 2); monofunctional alkoxysilanes such as trimethylmethoxysilane (c = 1), and the like. Trifunctional and tetrafunctional alkoxysilanes are preferable for improving the strength of the film, and monofunctional and bifunctional alkoxysilanes are desirable for improving the flexibility and film formability.

  In addition, a silicon-based hard coat agent produced mainly from these coupling agents can also be used. Commercially available hard coat agents include KP-85, X-40-9740, X-40-2239 (manufactured by Shin-Etsu Silicone), and AY42-440, AY42-441, AY49-208 (manufactured by Toray Dow Corning). Etc.) can be used.

  Further, in the curable resin composition for forming the protective layer 7, a compound having two or more silicon atoms as shown in the following general formula (XI) is used in order to increase the strength of the protective layer 7. Is also desirable.

B- (Si (R ⁵¹ ) _(3-d) Q _d ) ₂ (XI)
(In the above formula (XI), B represents a divalent organic group, R ⁵¹ represents a hydrogen atom, an alkyl group or a substituted or unsubstituted aryl group, Q represents a hydrolyzable group, and d represents an integer of 1 to 3. Is shown.)

  More specifically, as the compound represented by the general formula (XI), the following compounds (XI-1) to (XI-16) can be mentioned as desirable ones. Me represents a methyl group, and Et represents an ethyl group.

  Further, a resin soluble in an alcohol solvent or a ketone solvent may be added for controlling the film characteristics and extending the liquid life. Examples of such resins include polyvinyl butyral resins, polyvinyl formal resins, and polyvinyl acetal resins such as partially acetalized polyvinyl acetal resins in which a part of butyral has been modified with formal, acetoacetal, or the like (for example, ESREC B, K manufactured by Sekisui Chemical Co., Ltd.). Etc.), polyamide resin, cellulose resin, phenol resin and the like. In particular, polyvinyl acetal resin is desirable from the viewpoint of improving electrical characteristics.

  Various resins can be added for the purposes of discharge gas resistance, mechanical strength, scratch resistance, particle dispersibility, viscosity control, torque reduction, wear amount control, pot life extension, and the like. In this embodiment, it is desirable to further add a resin that dissolves in alcohol. Examples of resins soluble in alcohol solvents include polyvinyl butyral resins, polyvinyl formal resins, and polyvinyl acetal resins such as partially acetalized polyvinyl acetal resins in which a part of butyral has been modified with formal or acetoacetal (for example, manufactured by Sekisui Chemical Co., Ltd.) ESREC B, K, etc.), polyamide resin, cellulose resin and the like. In particular, polyvinyl acetal resin is desirable from the viewpoint of improving electrical characteristics.

  The weight average molecular weight of the resin is preferably 2,000 or more and 100,000 or less, and more preferably 5,000 or more and 50,000 or less. If the weight average molecular weight is less than 2,000, the desired effect tends not to be obtained. If the weight average molecular weight is more than 100,000, the solubility becomes low and the addition amount is limited, or the film formation may be poor during coating. Tend to. The addition amount is preferably 1% by mass to 40% by mass, more preferably 1% by mass to 30% by mass, and most preferably 5% by mass to 20% by mass. When the addition amount is less than 1% by mass, it is difficult to obtain a desired effect. When the addition amount is more than 40% by mass, image blurring at high temperature and high humidity is likely to occur. Moreover, although said resin may be used independently, you may mix and use them.

  In order to prolong pot life and control film properties, it is desirable to contain a cyclic compound having a repeating structural unit represented by the following general formula (XII) or a derivative from the compound.

In the above formula (XII), A ¹ and A ² each independently represent a monovalent organic group.

  Examples of the cyclic compound having a repeating structural unit represented by the general formula (XII) include commercially available cyclic siloxanes. Specifically, cyclic dimethylcyclosiloxanes such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, 1,3,5-trimethyl-1,3,5- Triphenylcyclotrisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetraphenylcyclotetrasiloxane, 1,3,5,7,9-pentamethyl-1,3,5,7 , 9-pentaphenylcyclopentasiloxane and other cyclic methylphenylcyclosiloxanes, hexaphenylcyclotrisiloxane and other cyclic phenylcyclosiloxanes, and 3- (3,3,3-trifluoropropyl) methylcyclotrisiloxane and other fluorine Atom-containing cyclosiloxanes, methylhydrosiloxa Mixture, pentamethylcyclopentasiloxane, mention may be made of phenyl hydrosilyl group-containing cyclosiloxanes of hydrocyclosiloxane like, cyclic siloxanes and vinyl group-containing cyclosiloxanes such as penta vinyl pentamethylcyclopentasiloxane like. These cyclic siloxane compounds may be used alone or in combination of two or more.

  Further, various particles may be added to the curable resin composition for forming the protective layer 7 in order to control the contamination resistance adhesion, lubricity, hardness, etc. of the surface of the electrophotographic photosensitive member. .

  An example of the particles may include silicon atom-containing particles. The silicon atom-containing particles are particles containing silicon as a constituent element, and specific examples include colloidal silica and silicone particles. The colloidal silica used as the silicon atom-containing particles preferably has a volume average particle diameter of 1 nm to 100 nm, more preferably 10 nm to 30 nm, and an acidic or alkaline aqueous dispersion, or an organic material such as alcohol, ketone, or ester. What was chosen from what was disperse | distributed in the solvent and generally marketed can be used. The solid content of colloidal silica in the curable resin composition is not particularly limited, but is desirable based on the total solid content in the curable resin composition in terms of film formability, electrical characteristics, and strength. Is used in the range of 0.1% by weight to 50% by weight, more preferably in the range of 0.1% by weight to 30% by weight.

  The silicone particles used as the silicon atom-containing particles are spherical and have a volume average particle diameter of preferably 1 nm to 500 nm, more preferably 10 nm to 100 nm, and the silicone resin particles, the silicone rubber particles, and the silicone surface-treated silica particles. Those selected and generally commercially available can be used.

  Silicone particles are small particles that are chemically inert and excellent in dispersibility in resins, and since the content required to obtain more sufficient properties is low, the crosslinking reaction is not hindered. The surface properties of the photographic photoreceptor can be improved. In other words, it improves the lubricity and water repellency of the surface of the electrophotographic photosensitive member while being uniformly incorporated in a strong cross-linked structure, and maintains good wear resistance and contamination resistance adhesion over a long period of time. Can do. The content of the silicone particles in the curable resin composition is desirably in the range of 0.1% by mass or more and 30% by mass or less, more preferably 0.5%, based on the total solid content in the curable resin composition. The range is from 10% by mass to 10% by mass.

Other particles include fluorine-based particles such as ethylene tetrafluoride, ethylene trifluoride, propylene hexafluoride, vinyl fluoride, vinylidene fluoride, and the 8th Polymer Materials Forum Lecture Proceedings p89. Particles made of a resin obtained by copolymerizing a fluororesin and a monomer having a hydroxyl group, ZnO—Al ₂ O ₃ , SnO ₂ —Sb ₂ O ₃ , In ₂ O ₃ —SnO ₂ , ZnO—TiO ₂ , ZnO Examples thereof include semiconductive metal oxides such as —TiO ₂ , MgO—Al ₂ O ₃ , FeO—TiO ₂ , TiO ₂ , SnO ₂ , In ₂ O ₃ , ZnO, and MgO.

  In addition, oil such as silicone oil can be added in order to control the contamination resistance adhesion, lubricity, hardness and the like of the electrophotographic photosensitive member surface. Examples of the silicone oil include silicone oils such as dimethylpolysiloxane, diphenylpolysiloxane, and phenylmethylsiloxane, amino-modified polysiloxane, epoxy-modified polysiloxane, carboxyl-modified polysiloxane, carbinol-modified polysiloxane, methacryl-modified polysiloxane, and mercapto. Examples include reactive silicone oils such as modified polysiloxanes and phenol-modified polysiloxanes. These may be added in advance to the curable resin composition for forming the protective layer 7, or may be impregnated under reduced pressure or increased pressure after producing the photoreceptor.

  Moreover, additives, such as a plasticizer, a surface modifier, antioxidant, and a photodegradation inhibitor, can also be contained. Examples of the plasticizer include biphenyl, biphenyl chloride, terphenyl, dibutyl phthalate, diethylene glycol phthalate, dioctyl phthalate, triphenyl phosphate, methyl naphthalene, benzophenone, chlorinated paraffin, polypropylene, polystyrene, and various fluorohydrocarbons.

  In addition, an antioxidant having a hindered phenol, hindered amine, thioether or phosphite partial structure can be added, which is effective in improving the potential stability and image quality when the environment changes.

  Examples of the antioxidant include the following compounds. For example, hindered phenols include “Sumilizer BHT-R”, “Sumizer MDP-S”, “Sumizer BBM-S”, “Sumizer WX-R”, “Sumizer NW”, “Sumizer BP-76”, "Sumilizer BP-101", "Sumilizer GA-80", "Sumilizer GM", "Sumilizer GS" (manufactured by Sumitomo Chemical Co., Ltd.), "IRGANOX1010", "IRGANOX1035", "IRGANOX1076", "IRGANOX1098", "IRGANOX1098", "IRGANOX1098" , “IRGANOX1141”, “IRGANOX1222”, “IRGANOX1330”, “IRGANOX1425WL”, “IRGAN X1520L "," IRGANOX245 "," IRGANOX259 "," IRGANOX3114 "," IRGANOX3790 "," IRGANOX5057 "," IRGANOX565 "(above, manufactured by Ciba Specialty Chemicals)," Adekastab AO-20 "," Adekastab AO-30 " , "ADK STAB AO-40", "ADK STAB AO-50", "ADK STAB AO-60", "ADK STAB AO-70", "ADK STAB AO-80", "ADK STAB AO-330" (manufactured by ADK), Hin Dirtamines include “Sanol LS2626”, “Sanol LS765”, “Sanol LS770”, “Sanol LS744” (manufactured by Sankyo Lifetech Co., Ltd.), “Tinuvin 144”, “Tinuvin 622LD” ( As described above, Ciba Specialty Chemicals Co., Ltd., “Mark LA57”, “Mark LA67”, “Mark LA62”, “Mark LA68”, “Mark LA63” (above, manufactured by ADEKA), “Sumilyzer TPS” (above, Sumitomo Chemical) Manufactured by Sumitomo Chemical Co., Ltd.), and as phosphite systems, “Mark 2112”, “Mark PEP / 8”, “Mark PEP-24G”, “ Mark PEP · 36 ”,“ Mark 329K ”,“ Mark HP · 10 ”(manufactured by Adeka), and hindered phenols and hindered amine antioxidants are particularly desirable. Furthermore, these may be modified with a substituent such as an alkoxysilyl group capable of undergoing a crosslinking reaction with the material forming the crosslinked film.

Further, in order to remove the catalyst during synthesis from a resin having a crosslinked structure such as a phenol resin, a melamine resin, or a benzoguanamine resin, the resin is dissolved in an appropriate solvent such as methanol, ethanol, toluene, ethyl acetate, and washed with water. It is desirable to perform a treatment such as reprecipitation using a poor solvent, or to perform treatment using, for example, the materials exemplified below. Such materials include Amberlite 15, Amberlite 200C, Amberlist 15E (above, manufactured by Rohm and Haas), Dowex MWC-1-H, Dowex 88, Dowex HCR-W2 (above, Dow Chemical Co., Ltd.), Levacit SPC-108, Levacit SPC-118 (manufactured by Bayer), Diaion RCP-150H (Mitsubishi Kasei), Sumikaion KC-470, Duolite C26-C, Duolite C-433 Cation exchange resins such as Duolite-464 (manufactured by Sumitomo Chemical Co., Ltd.) and Nafion-H (manufactured by DuPont); Amberlite IRA-400, Amberlite IRA-45 (above, Rohm and Haas) Anion exchange resin such as Zr (O ₃ PCH ₂ CH ₂ SO) ₃ H) ₂ , Th (O ₃ PCH ₂ CH ₂ COOH) Inorganic solid having a group containing a proton acid group such as ₂ bonded to the surface; containing a proton acid group such as a polyorganosiloxane having a sulfonic acid group Polyorganosiloxanes; heteropolyacids such as cobalt tungstic acid and phosphomolybdic acid; isopolyacids such as niobic acid, tantalum acid and molybdic acid; unitary metal oxides such as silica gel, alumina, chromia, zirconia, CaO and MgO; silica - alumina, silica - magnesia, silica - zirconia, composite-based metal oxides such as zeolites; acid clay, activated clay, montmorillonite, clay mineral such as kaolinite; LiSO _4, metal sulfates, such as MgSO _4; phosphate zirconia , metal phosphates such as lanthanum phosphate; LiNO , Mn (NO ₃₎ metal nitrate such as _2; inorganic group containing an amino group such as solid obtained by reacting aminopropyltriethoxysilane on silica gel is bonded to a surface solid; amino-modified silicone resin And polyorganosiloxanes containing amino groups such as

  In addition, in order to adjust film properties such as hardness, adhesion, and flexibility, epoxy-containing compounds such as polyglycidyl methacrylate, glycidyl bisphenols, phenol epoxy resins, terephthalic acid, maleic acid, pyromellitic acid, biphenyltetra Carboxylic acids or the like or anhydrides thereof may be added. The addition amount is preferably 0.05 parts by weight or more and 1 part by weight or less, more preferably 0.1 parts by weight or more and 0.7 parts by weight or less, with respect to 1 part by weight of the electrophotographic photoreceptor additive of the present embodiment. Used in

  Furthermore, polyvinyl butyral resin, polyarylate resin (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin, polyacrylamide resin, Insulating resins such as polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, and polyvinyl pyrrolidone resin can be mixed at a desired ratio. Thereby, the adhesiveness with the electric charge transport layer 6, the coating film defect by heat shrink or repellency, etc. can also be suppressed.

  The protective layer 7 is formed using a coating liquid for forming a protective layer containing the above-described constituent materials. That is, the protective layer 7 is formed by applying a coating liquid for forming a protective layer on the charge transport layer 6 and curing it.

  In the coating solution for forming the protective layer, a solvent such as alcohols such as methanol, ethanol, propanol and butanol; ketones such as acetone and methyl ethyl ketone; tetrahydrofuran; ethers such as diethyl ether and dioxane is used as necessary. . In addition to these, various solvents can be used, but in order to apply the dip coating method generally used in the production of electrophotographic photoreceptors, alcohol-based or ketone-based solvents, or mixed solvents thereof Is preferred. The boiling point is preferably 50 ° C. or higher and 150 ° C. or lower, and can be arbitrarily mixed and used. The amount of the solvent can be arbitrarily set, but if it is too small, it is likely to precipitate. 1 to 20 parts by mass is more desirable.

  Furthermore, when crosslinking, a curing catalyst may be used in the protective layer forming coating solution. Curing catalysts include bissulfonyldiazomethanes such as bis (isopropylsulfonyl) diazomethane, bissulfonylmethanes such as methylsulfonyl p-toluenesulfonylmethane, sulfonylcarbonyldiazomethanes such as cyclohexylsulfonylcyclohexylcarbonyldiazomethane, 2-methyl Sulfonylcarbonyl alkanes such as 2- (4-methylphenylsulfonyl) propiophenone, nitrobenzyl sulfonates such as 2-nitrobenzyl p-toluenesulfonate, alkyl and aryl sulfonates such as pyrogallol trismethanesulfonate ( g) Benzoinsulfonates such as benzoin tosylate, N such as N- (trifluoromethylsulfonyloxy) phthalimide Sulfonyloxyimides, pyridones such as (4-fluorobenzenesulfonyloxy) -3,4,6-trimethyl-2-pyridone, 2,2,2-trifluoro-1-trifluoromethyl-1- (3 -Photoacid generators such as sulfonic acid esters such as vinylphenyl) -ethyl-4-chlorobenzenesulfonate, onium salts such as triphenylsulfonium methanesulfonate, diphenyliodonium trifluoromethanesulfonate, protonic acids or Lewis acids. Preferred examples include a compound neutralized with a base, a mixture of Lewis acid and trialkyl phosphate, sulfonate esters, phosphate esters, onium compounds, and carboxylic anhydride compounds.

Compounds obtained by neutralizing a protonic acid or Lewis acid with a Lewis base include halogenocarboxylic acids, sulfonic acids, sulfuric monoesters, phosphoric mono- and diesters, polyphosphoric esters, boric mono- and diesters, and ammonia. Various amines such as monoethylamine, triethylamine, pyridine, piperidine, aniline, morpholine, cyclohexylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, etc. or trialkylphosphine, triarylphosphine, trialkylphosphite, triaryl Compounds neutralized with phosphite, and also commercially available Necura 2500X, 4167, X-47-110, 3525, 5225 as acid-base blocking catalysts (trade name, Packaging Industry Co., Ltd.), and the like. Examples of the compound obtained by neutralizing a Lewis acid with a Lewis base include compounds obtained by neutralizing a Lewis acid such as BF ₃ , FeCl ₃ , SnCl ₄ , AlCl ₃ , ZnCl ₂ with the above Lewis base.

  Examples of the onium compound include triphenylsulfonium methanesulfonate, diphenyliodonium trifluoromethanesulfonate, and the like.

  Examples of the carboxylic anhydride compound include acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, lauric anhydride, oleic anhydride, stearic anhydride, n-caproic anhydride, n-caprylic anhydride, and n-capric anhydride. , Palmitic anhydride, myristic anhydride, trichloroacetic anhydride, dichloroacetic anhydride, monochloroacetic anhydride, trifluoroacetic anhydride, heptafluorobutyric anhydride, and the like.

  Specific examples of Lewis acids include, for example, boron trifluoride, aluminum trichloride, ferrous chloride, ferric chloride, ferrous chloride, ferric chloride, zinc chloride, zinc bromide, stannous chloride. , Metal halides such as stannic chloride, stannous bromide, stannic bromide, organometallic compounds such as trialkylboron, trialkylaluminum, dialkylaluminum halide, monoalkylaluminum halide, tetraalkyltin , Diisopropoxyethyl acetoacetate aluminum, tris (ethyl acetoacetate) aluminum, tris (acetylacetonato) aluminum, diisopropoxy bis (ethyl acetoacetate) titanium, diisopropoxy bis (acetylacetonato) titanium, tetrakis (N-propylacetoacetate Zirconium, tetrakis (acetylacetonato) zirconium, tetrakis (ethylacetoacetate) zirconium, dibutyl bis (acetylacetonato) tin, tris (acetylacetonato) iron, tris (acetylacetonato) rhodium, bis (acetyl) Acetonato) zinc, tris (acetylacetonato) cobalt metal chelate compounds, dibutyltin dilaurate, dioctyltin ester malate, magnesium naphthenate, calcium naphthenate, manganese naphthenate, iron naphthenate, cobalt naphthenate, copper naphthenate , Zinc naphthenate, zirconium naphthenate, lead naphthenate, calcium octylate, manganese octylate, iron octylate, cobalt octylate, zinc octylate, zirconium octylate, Tin chill acid, lead octylate, zinc laurate, magnesium stearate, aluminum stearate, calcium stearate, cobalt stearate, zinc stearate, and metal soaps such as stearate lead. These may be used individually by 1 type and may be used in combination of 2 or more type.

  The amount of these catalysts used is not particularly limited, but is preferably 0.1 parts by mass or more and 20 parts by mass or less, and 0.3 parts by mass with respect to a total of 100 parts by mass of the solid content contained in the protective layer forming coating solution. The amount of 10 parts by mass or less is particularly preferable.

  When the coating liquid for forming the protective layer is applied onto the charge transport layer 6, the coating methods are blade coating method, Mayer bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain coating. Ordinary methods such as a method can be used. And after application | coating, the protective layer 7 is formed by drying a coating film.

  In addition, in the case of application | coating, when a required film thickness cannot be obtained by one application | coating, a required film thickness can be obtained by apply | coating several times. When performing multiple times of repeated application, the heat treatment may be performed at each application, or may be performed after being applied multiple times.

  When the protective layer 7 is formed using a resin having a crosslinked structure, the curing temperature is desirably 100 ° C. or more and 170 ° C. or less, more desirably 100 ° C. or more and 160 ° C. or less when crosslinking is performed. The curing time is preferably 30 minutes or more and 2 hours or less, more preferably 30 minutes or more and 1 hour or less, and the heating temperature may be changed to another stage.

  The atmosphere in which the crosslinking reaction is performed can be prevented in a gas atmosphere inert to so-called oxidation such as nitrogen, helium, and argon, thereby preventing deterioration of electrical characteristics. When the crosslinking reaction is performed in an inert gas atmosphere, the curing temperature can be set higher than in an air atmosphere, and the curing temperature is desirably 100 ° C. or higher and 180 ° C. or lower, more desirably 110 ° C. or higher and 160 ° C. or lower. It is. Further, the curing time is desirably 30 minutes or more and 2 hours or less, and more desirably 30 minutes or more and 1 hour or less.

  The thickness of the protective layer 7 is preferably 0.5 μm or more and 15 μm or less, more preferably 1 μm or more and 10 μm or less, and further preferably 1 μm or more and 5 μm or less.

Oxygen permeability at 25 ° C. of the protective layer 7 is preferably not more than ^{4 × 10 12 fm / s ·} Pa, more preferably not more than ^{3.5 × 10 12 fm / s ·} Pa, 3 × 10 More preferably, it is ¹² fm / s · Pa or less.

  Here, the oxygen permeation coefficient is a scale representing the ease of oxygen gas permeation of the layer, but it can also be regarded as a substitute characteristic of the physical gap ratio of the layer if the view is changed. Note that the absolute value of the transmittance changes if the type of gas changes, but there is almost no reversal of the magnitude relationship between the layers that are the specimens. Therefore, the oxygen permeation coefficient may be interpreted as a measure expressing the general ease of gas permeation.

  That is, when the oxygen permeation coefficient at 25 ° C. of the protective layer 7 satisfies the above conditions, the gas hardly penetrates into the protective layer 7. Therefore, the permeation of the discharge product generated by the image forming process is suppressed, the deterioration of the compound contained in the protective layer 7 is suppressed, the electrical characteristics can be maintained at a high level, and the image quality is improved and the life is extended. It is valid.

  In the electrophotographic photoreceptor 1, when a single-layer type photosensitive layer is formed, the single-layer type photosensitive layer is formed containing a charge generating material and a binder resin. The charge generation material is the same as that used for the charge generation layer in the function separation type photosensitive layer, and the binder resin is a binder resin used for the charge generation layer and the charge transport layer in the function separation type photosensitive layer. Similar ones can be used. The content of the charge generating material in the single layer type photosensitive layer is preferably 10% by mass or more and 85% by mass or less, more preferably 20% by mass or more and 50% by mass or less, based on the total solid content in the single layer type photosensitive layer. is there. A charge transport material or a polymer charge transport material may be added to the single-layer type photosensitive layer for the purpose of improving photoelectric characteristics. The addition amount is preferably 5% by mass or more and 50% by mass or less based on the total solid content in the single-layer type photosensitive layer. Moreover, the solvent and coating method used for coating can be the same as those for the above layers. The film thickness of the single-layer type photosensitive layer is preferably about 5 μm to 50 μm, and more preferably 10 μm to 40 μm.

  Next, the developing device 25 will be described. The developing device 25 develops the electrostatic latent image on the electrophotographic photosensitive member 1 to form a toner image.

  The toner used for the developing device 25 will be described.

As such a toner, an average shape factor SF1 (SF1 = (ML ² / A) × (π / 4) × 100 (where ML represents the maximum length (μm) of particles), and A represents a particle projection surface (μm ^2). )) Is preferably from 100 to 150, more preferably from 100 to 140. The average shape factor (SF1) is an image of toner particles placed on a glass slide through a video camera. , Measured with an optical microscope, taken into an image analyzer (LUZEXIII, manufactured by NIRECO), calculated the maximum toner length (ML) and projected area (A), and substituted these values into the above formula to calculate the shape factor. The average shape factor is an average value of the shape factors calculated from the above formula for 100 arbitrary toner particles.

  Further, the toner preferably has a volume average particle size of 2 μm or more and 12 μm or less, more preferably 3 μm or more and 12 μm or less, and further preferably 3 μm or more and 9 μm or less. By using a toner satisfying such an average shape factor and volume average particle size, an image with high development, transferability, and high image quality can be obtained.

  The toner is not particularly limited by the production method as long as it satisfies the above average shape factor and volume average particle diameter. For example, the toner may be a binder resin, a colorant, a release agent, and the like. A kneading and pulverizing method in which a charge control agent is added, kneading, pulverizing, and classifying; a method in which the particles obtained by the kneading and pulverizing method are changed in shape by mechanical impact force or thermal energy; Emulsion polymerization of the body, and the resulting dispersion is mixed with a dispersion of a colorant, a release agent and, if necessary, a charge control agent, and agglomerated and heat-fused to obtain toner particles. Suspension polymerization method in which a polymerizable monomer for obtaining a binder resin, a colorant, a release agent, and a charge control agent, if necessary, are suspended in an aqueous solvent and polymerized; Solutions of resin, colorant and release agent, and charge control agent as required The toner is used which is suspended in an aqueous solvent is prepared by dissolution suspension method or the like to be granulated.

  Further, a known method such as a production method in which the toner obtained by the above method is used as a core, and agglomerated particles are further adhered and heat-fused to give a core-shell structure can be used. The toner production method is preferably a suspension polymerization method, an emulsion polymerization aggregation method, or a dissolution suspension method in which an aqueous solvent is used from the viewpoint of shape control and particle size distribution control, and an emulsion polymerization aggregation method is particularly preferable.

  The toner base particles include a binder resin, a colorant, and a release agent, and include silica and a charge control agent if necessary.

  Binder resins used for toner base particles include styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene and isoprene, vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, etc. Α-methylene aliphatics such as vinyl esters, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate Homopolymers and copolymers of monocarboxylic acid esters, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl butyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropenyl ketone , Polyester resins by copolymerization of dicarboxylic acids and diols.

  Particularly representative binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. A polymer, polyethylene, polypropylene, a polyester resin, etc. can be mentioned. In addition, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like can also be mentioned.

  In addition, as colorants, magnetic powders such as magnetite and ferrite, carbon black, aniline blue, caryl blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, Lamp Black, Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 can be exemplified as a representative one.

  Typical examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, Fischer tropic wax, montan wax, carnauba wax, rice wax, and candelilla wax.

  As the charge control agent, known ones can be used, and azo metal complex compounds, metal complex compounds of salicylic acid, and resin type charge control agents containing polar groups can be used. When the toner is manufactured by a wet manufacturing method, it is preferable to use a material that is difficult to dissolve in water in terms of controlling ionic strength and reducing wastewater contamination. The toner may be either a magnetic toner containing a magnetic material or a non-magnetic toner containing no magnetic material.

  The toner used in the developing device 25 can be produced by mixing the toner base particles and the external additive with a Henschel mixer or a V blender. In addition, when the toner base particles are produced by a wet method, external addition can also be performed by a wet method.

  Lubricating particles may be added to the toner used in the developing device 25. Lubricating particles include solid lubricants such as graphite, molybdenum disulfide, talc, fatty acids and fatty acid metal salts, low molecular weight polyolefins such as polypropylene, polyethylene and polybutene, silicones having a softening point upon heating, oleic amides Aliphatic amides such as erucic acid amide, ricinoleic acid amide, stearic acid amide, etc., plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil, animals such as beeswax Minerals such as system waxes, montan waxes, ozokerites, ceresins, paraffin waxes, microcrystalline waxes, Fischer-Tropsch waxes, petroleum based waxes, and modified products thereof can be used. These can be used alone or in combination of two or more. However, the volume average particle diameter is preferably in the range of 0.1 μm or more and 10 μm or less, and the above chemical structure may be pulverized to make the particle diameter uniform. The amount added to the toner is desirably in the range of 0.05% by mass to 2.0% by mass, and more desirably in the range of 0.1% by mass to 1.5% by mass.

  To the toner used in the developing device 25, inorganic particles, organic particles, composite particles obtained by attaching inorganic particles to the organic particles, and the like can be added for the purpose of removing the adhered matter and deteriorated matter on the surface of the electrophotographic photosensitive member. .

  Inorganic particles include silica, alumina, titania, zirconia, barium titanate, aluminum titanate, strontium titanate, magnesium titanate, zinc oxide, chromium oxide, cerium oxide, antimony oxide, tungsten oxide, tin oxide, tellurium oxide, Various inorganic oxides such as manganese oxide, boron oxide, silicon carbide, boron carbide, titanium carbide, silicon nitride, titanium nitride, and boron nitride, nitrides, borides, and the like are preferably used.

  In addition, the inorganic particles may be mixed with titanium coupling agents such as tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzene sulfonyl titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, γ- (2- Aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxy Silane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane The treatment may be performed with a silane coupling agent such as run, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, and p-methylphenyltrimethoxysilane. In addition, those hydrophobized with higher fatty acid metal salts such as silicone oil, aluminum stearate, zinc stearate and calcium stearate are also preferably used.

  Examples of the organic particles include styrene resin particles, styrene acrylic resin particles, polyester resin particles, and urethane resin particles.

  As the particle diameter, a volume average particle diameter of preferably 5 nm to 1,000 nm, more preferably 5 nm to 800 nm, and further preferably 5 nm to 700 nm is used. If the volume average particle diameter is less than the lower limit, the polishing ability tends to be lacking. On the other hand, if the volume average particle diameter exceeds the upper limit, the surface of the electrophotographic photosensitive member tends to be damaged. Moreover, it is preferable that the sum of the addition amount of the particle | grains mentioned above and lubricity particle | grains is 0.6 mass% or more.

  As other inorganic oxides added to the toner, a small-diameter inorganic oxide having a primary particle size of 40 nm or less is used for powder fluidity, charge control, etc. It is preferable to add a larger-diameter inorganic oxide. Known inorganic oxide particles can be used, but it is preferable to use silica and titanium oxide in combination for precise charge control. Further, the surface treatment of the small-diameter inorganic particles increases the dispersibility and increases the effect of increasing the powder fluidity. Furthermore, it is also preferable to add carbonates such as calcium carbonate and magnesium carbonate and inorganic minerals such as hydrotalcite in order to remove the discharge purified product.

  In addition, the color toner for electrophotography is used by mixing with a carrier. As the carrier, iron powder, glass beads, ferrite powder, nickel powder, or those having a resin coating on the surface thereof are used. The mixing ratio with the carrier can be set as appropriate.

  The cleaning device 27 includes a fibrous member (roll shape) 27a and a cleaning blade (blade member) 27b.

Although the cleaning device 27 is provided with the fibrous member 27a and the cleaning blade 27b, the cleaning device 27 may be provided with either one. The fibrous member 27a may have a toothbrush shape in addition to the roll shape. Further, the fibrous member 27a may be fixed to the cleaning device main body, may be supported so as to be rotatable, and may be supported so as to be capable of oscillating in the photosensitive member axial direction. As the fibrous member 27a, polyester, nylon, acrylic, etc., cloth-like ones made of ultrafine fibers such as Toraysee (made by Toray Industries), resin fibers such as nylon, acrylic, polyolefin, polyester, etc. are used as a substrate or carpet. The brush-like thing etc. which were flocked to can be mentioned. Further, as the fibrous member 27a, a conductive powder or an ionic conductive agent is added to the above-described material to impart conductivity, or a conductive layer is formed inside or outside of each fiber. Can also be used. When conductivity is imparted, the resistance value of the single fiber is preferably 10 ² Ω or more and 10 ⁹ Ω or less. The fiber thickness of the fibrous member 27a is desirably 30 d (denier) or less, more desirably 20 d or less, and the fiber density is desirably 20,000 fibers / inch ² or more, more desirably 30,000 fibers / inch. inch ² or more.

  The cleaning device 27 is required to remove deposits (for example, discharge products) on the surface of the photoreceptor with a cleaning blade and a cleaning brush. In order to achieve this object over a long period of time and stabilize the function of the cleaning member, it is desirable to supply the cleaning member with a lubricating substance (lubricating component) such as metal soap, higher alcohol, wax, or silicone oil.

  For example, when a roll-shaped member is used as the fibrous member 27a, it is desirable to supply a lubricating component to the surface of the electrophotographic photoreceptor by bringing it into contact with a lubricating substance such as metal soap or wax. A normal rubber blade is used as the cleaning blade 27b. As described above, when a rubber blade is used as the cleaning blade 27b, supplying a lubricating component to the surface of the electrophotographic photosensitive member is particularly effective in suppressing chipping and wear of the blade.

  The process cartridge 20 described above is detachable from the image forming apparatus main body, and constitutes the image forming apparatus together with the image forming apparatus main body.

  The exposure device 30 may be any device that exposes the charged electrophotographic photosensitive member 1 to form an electrostatic latent image. Further, it is desirable to use a multi-beam surface emitting laser as the light source of the exposure apparatus 30.

  The transfer device 40 may be any device that transfers the toner image on the electrophotographic photosensitive member 1 to a transfer medium (intermediate transfer member 50). For example, a roll-shaped one that is usually used is used.

  As the intermediate transfer member 50, a belt-like member (intermediate transfer belt) made of polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber or the like having semiconductivity is used. Further, as the form of the intermediate transfer member 50, a drum-like member can be used in addition to the belt-like member. There is also a direct transfer type image forming apparatus that does not include the intermediate transfer member.

  The medium to be transferred is not particularly limited as long as it is a medium for transferring a toner image formed on the electrophotographic photosensitive member 1. For example, when transferring directly from the electrophotographic photosensitive member 1 to paper or the like, paper or the like is a transfer medium, and when the intermediate transfer member 50 is used, the intermediate transfer member is a transfer medium.

  FIG. 3 is a schematic diagram illustrating another example of the image forming apparatus according to the present embodiment. In the image forming apparatus 110 shown in FIG. 3, the electrophotographic photosensitive member 1 is fixed to the main body of the image forming apparatus, and the charging device 21, the developing device 25, and the cleaning device 27 are each formed into a cartridge. It is provided independently as a cleaning cartridge.

  In the image forming apparatus 110, the electrophotographic photosensitive member 1 and other devices are separated, and the charging device 21, the developing device 25, and the cleaning device 27 are screwed, caulked, bonded, or welded to the image forming apparatus main body. Without being fixed, it can be removed by pulling and pushing.

  When an electrophotographic photoreceptor excellent in wear resistance is used, it may not be necessary to make a cartridge. Therefore, the charging device 21, the developing device 25, or the cleaning device 27 can be detached from the main body without being fixed to the main body by screws, caulking, adhesion, welding, or the like, and can be attached and detached by an operation by pulling and pushing. The member cost per print can be reduced. Further, two or more of these devices can be detachable as an integrated cartridge, thereby further reducing the member cost per print.

  The image forming apparatus 110 has the same configuration as that of the image forming apparatus 100 except that the charging device 21, the developing device 25, and the cleaning device 27 are each formed as a cartridge.

  FIG. 4 is a schematic diagram illustrating another example of the image forming apparatus according to the present embodiment. The image forming apparatus 120 is a tandem full-color image forming apparatus equipped with four process cartridges 20. In the image forming apparatus 120, four process cartridges 20 are arranged in parallel on the intermediate transfer member 50, and one electrophotographic photosensitive member can be used for one color. The image forming apparatus 120 has the same configuration as that of the image forming apparatus 100 except that it is a tandem system.

  FIG. 5 is a schematic diagram illustrating another example of the image forming apparatus according to the present embodiment. The image forming apparatus 130 shown in FIG. 5 is a so-called four-cycle image forming apparatus that forms toner images of a plurality of colors with one electrophotographic photosensitive member. The image forming apparatus 130 includes a photosensitive drum 1 that is rotated by a driving device (not shown) at a predetermined rotational speed in the direction of arrow A in the figure, and above the photosensitive drum 1 is a photosensitive member. A charging device 21 for charging the outer peripheral surface of the drum 1 is provided.

  Further, an exposure device 30 having a surface emitting laser array as an exposure light source is disposed above the charging device 21. The exposure device 30 modulates a plurality of laser beams emitted from a light source in accordance with an image to be formed and deflects the laser beams in the main scanning direction so that the axis of the photosensitive drum 1 is on the outer peripheral surface of the photosensitive drum 1. Scan in parallel. Thereby, an electrostatic latent image is formed on the outer peripheral surface of the charged photosensitive drum 1.

  A developing device 25 is disposed on the side of the photosensitive drum 1. The developing device 25 includes a roll-shaped container that is rotatably arranged. Four containers are formed inside the container, and developing units 25Y, 25M, 25C, and 25K are provided in each container. Each of the developing units 25Y, 25M, 25C, and 25K includes a developing roll 26, and stores therein toners of yellow (Y), magenta (M), cyan (C), and black (K), respectively.

  The full-color image is formed by the image forming apparatus 130 when the photosensitive drum 1 forms an image four times. That is, while the photosensitive drum 1 forms an image four times, the charging device 21 charges the outer peripheral surface of the photosensitive drum 1, and the exposure device 30 displays Y, M, C, and K images representing the color image to be formed. Scanning the outer peripheral surface of the photosensitive drum 1 with a laser beam modulated according to any of the data switches the image data used for modulation of the laser beam every time the photosensitive drum 1 forms an image. Repeat while. Further, the developing device 25 operates the developing device corresponding to the outer peripheral surface in a state where any of the developing rolls 26 of the developing devices 25Y, 25M, 25C, and 25K corresponds to the outer peripheral surface of the photosensitive drum 1. The photosensitive drum 1 develops the electrostatic latent image formed on the outer peripheral surface of the photoconductive drum 1 to a specific color and forms a toner image of the specific color on the outer peripheral surface of the photoconductive drum 1. Each time the image is formed, the process is repeated while rotating the container so that the developing unit used for developing the electrostatic latent image is switched. Thus, every time the photosensitive drum 1 forms an image, toner images of Y, M, C, and K are sequentially formed on the outer peripheral surface of the photosensitive drum 1.

  Further, an endless intermediate transfer belt 50 is disposed below the photosensitive drum 1. The intermediate transfer belt 50 is wound around rolls 51, 53, and 55, and is arranged so that the outer peripheral surface is in contact with the outer peripheral surface of the photosensitive drum 1. The rolls 51, 53, and 55 are rotated by transmission of a driving force of a motor (not shown) to rotate the intermediate transfer belt 50 in the direction of arrow B in FIG.

  A transfer device (transfer device) 40 is disposed on the opposite side of the photosensitive drum 1 with the intermediate transfer belt 50 interposed therebetween, and Y, M, C, and K formed sequentially on the outer peripheral surface of the photosensitive drum 1. The toner images are transferred one color at a time to the image forming surface of the intermediate transfer belt 50 by the transfer device 40, and finally all the Y, M, C, and K images are laminated on the intermediate transfer belt 50.

  A lubricant supply device 31 and a cleaning device 27 are disposed on the outer peripheral surface of the photosensitive drum 1 on the opposite side of the developing device 25 with the photosensitive drum 1 interposed therebetween. When the toner image formed on the outer peripheral surface of the photosensitive drum 1 is transferred to the intermediate transfer belt 50, the lubricant is supplied to the outer peripheral surface of the photosensitive drum 1 by the lubricant supply device 31. The area that has held the transferred toner image is cleaned by the cleaning device 27.

  A sheet receiver 60 is disposed below the intermediate transfer belt 50, and a plurality of sheets P as recording materials (transfer media) are accommodated in the sheet receiver 60 in a stacked state. A take-out roll 61 is disposed obliquely above and to the left of the paper receiver 60, and a roll pair 63 and a roll 65 are arranged in this order on the downstream side in the take-out direction of the paper P by the take-out roll 61. The recording paper located in the uppermost position in the stacked state is taken out from the paper receiver 60 when the take-out roll 61 is rotated, and is conveyed by the roll pair 63 and the roll 65.

  A transfer device 42 is disposed on the opposite side of the roll 55 with the intermediate transfer belt 50 interposed therebetween. The paper P conveyed by the roll pair 63 and the roll 65 is sent between the intermediate transfer belt 50 and the transfer device 42, and the toner image formed on the image forming surface of the intermediate transfer belt 50 is transferred by the transfer device 42. . A fixing device 44 having a pair of fixing rolls is disposed downstream of the transfer device 42 in the transport direction of the paper P. The paper P on which the toner image is transferred is transferred to the paper P by the fixing device 44. After being fused and fixed, it is discharged out of the image forming apparatus 130 and placed on a paper discharge tray (not shown).

  The configuration of the process cartridge according to the present embodiment and the image forming apparatus according to the present embodiment are not particularly limited, and may be a known configuration.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail more concretely, this invention is not limited to a following example.

<Production of photoconductor>
First, a cylindrical aluminum substrate having an outer diameter of Φ84 mm subjected to a honing process was prepared. Next, 100 parts by mass of a zirconium compound (trade name: Orgatics ZC540, manufactured by Matsumoto Pharmaceutical Co., Ltd.), 10 parts by mass of a silane compound (trade name: A1100, manufactured by Nihon Unicar), 400 parts by mass of isopropanol, and butanol 200 parts by mass was mixed to obtain a coating solution for forming the undercoat layer. This coating solution was dip-coated on an aluminum substrate and dried by heating at 150 ° C. for 10 minutes to form an undercoat layer having a thickness of 0.1 μm.

  Next, the Bragg angle (2θ ± 0.2 °) in the CuKα characteristic X-ray diffraction spectrum is 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1. 1 part by weight of hydroxygallium phthalocyanine having a strong diffraction peak at 0 ° and 28.3 °, 1 part by weight of polyvinyl butyral (ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.), and 100 parts by weight of n-butyl acetate are mixed. Further, the mixture was treated with a glass shaker with a paint shaker for 1 hour and dispersed to obtain a coating solution for forming a charge generation layer. This coating solution was dip-coated on the undercoat layer and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of about 0.15 μm.

  Next, 2 parts by mass of the charge transport material represented by the following formula (VI-1), and 3 parts by mass of the polymer compound having a structural unit represented by the following formula (VI-2) (viscosity average molecular weight 50,000) , And 20 parts by mass of chlorobenzene were mixed to obtain a coating solution for forming a charge transport layer.

  The obtained charge transport layer forming coating solution was applied onto the charge generation layer by a dip coating method and heated at 110 ° C. for 40 minutes to form a charge transport layer having a thickness of 20 μm. In this way, the photoreceptor in which the undercoat layer, the charge generation layer, and the charge transport layer were formed on the honing-treated aluminum substrate was designated as “Photoreceptor 1”.

  Next, 500 parts by mass of Super Becamine (R) L-148-55 (butylated benzoguanamine resin: manufactured by Dainippon Ink & Co.) was dissolved in 500 parts by mass of toluene, and each was washed four times with 400 mL of distilled water. The conductivity of the final wash water was 8 μS / cm. The solvent was distilled off from the solution under reduced pressure to obtain 250 parts by weight of a candy-like resin. This is designated as guanamine resin-A1. Here, the electrical conductivity was measured at room temperature (about 20 ° C.) using washing water with a direct conductivity meter (Conductivity Meter DS-12: manufactured by HORIBA, Ltd.).

  The above guanamine resin-A1: 2 parts by mass, 97 parts by mass of a compound represented by the following structural formula (A), 1.7 parts by mass of 3,5-di-t-butyl-4-hydroxytoluene (BHT) as an antioxidant , 0.2 parts by weight of dodecylbenzenesulfonic acid, 0.1 parts by weight of leveling agent BYK-302 (manufactured by Big Chemie Japan Co., Ltd.), 8 parts by weight of 1-methoxy-2-propanol, and a coating solution for protective layer Was prepared. This coating solution is applied on the photoreceptor 1 formed up to the charge transport layer by dip coating, air-dried at room temperature for 30 minutes, cured by heating at 150 ° C. for 1 hour, and a protective layer having a thickness of about 6 μm. To form a photoconductor. The obtained photoreceptor is referred to as “Photoreceptor 2”.

(A)

<Production of cleaning member>
The urethane foam (polyurethane RR80) shown in Table 2 was cut into a size of 20 mm × 20 mm × 250 mm to obtain a charging member cleaning pad (cleaning member a).

  Furthermore, after inserting a core material made of SUS303 with an outer diameter of 5 mm and a length of 230 mm into the cut urethane foam, and bonding the core material and the urethane foam with a hot melt adhesive, the urethane from each end of the core material to 5 mm positions The foam was cut off to obtain an elastic roll material. Grinding was performed to obtain a charging member cleaning roll (cleaning member a) having an outer diameter of 9 mm.

  A charging member cleaning roll (cleaning member b) was obtained in the same manner except that the urethane foam (polyurethane RSC) shown in Table 2 was used.

( Reference Example 1)
<Preparation of charging roll>
[Formation of conductive elastic layer]
A mixture having the composition shown in Table 3 (the mixing ratio in Table 3 is part by mass) was kneaded with an open roll, and the diameter of the conductive support made of SUS303 was 8 mm in diameter using a press molding machine through an adhesive layer. A 15 mm roll was formed. Thereafter, conductive elastic rolls A and B having a diameter of 14 mm were obtained by polishing. Table 3 shows the results of Asker C hardness obtained by measuring the hardness of the conductive elastic rolls A and B using an Asker rubber hardness meter C type manufactured by Kobunshi Keiki Co., Ltd.

[Formation of surface layer]
A dispersion obtained by diluting 15 parts by mass of a mixture having the composition shown in Reference Example 1 in Table 4 (the mixing ratio in Table 4 is part by mass) with 85 parts by mass of methanol and dispersing the mixture with a bead mill is used as the conductive elastic material. After dip-coating on the surface of roll C, heating was performed at 180 ° C. for 30 minutes to crosslink and dry to form a surface layer having a thickness of 10 μm, whereby charging roll 1 was obtained.

[Measurement of degree of crosslinking]
After peeling off only the surface layer from the charging roll coated with the surface layer, the weight <1> is measured. Then, it is immersed in a glass bottle containing methanol and left overnight. After leaving, the methanol in the glass bottle is filtered together with the surface layer, the filtrate is sufficiently dried, and the surface layer weight <2> after drying is measured. Based on the measured weight, the degree of crosslinking was calculated by the following formula. The results are shown in Table 4.
Degree of crosslinking = 100 × (surface layer weight <1> −surface layer weight <2>) / (surface layer weight <1>)

Moreover, about the bridge | crosslinking state, it confirmed by performing GC-MS analysis as follows.
[Thermal desorption equipment]
Apparatus: Double Shot Pyrolyzer PY-2010D (manufactured by Frontier Laboratories)
Heating temperature: 180 ° C
Interface temperature: 200 ° C
[GC]
Apparatus: HP6890 GC System (manufactured by Hewlett-Packard Company)
Column: Agilent 19091S-433 HP5MS (5% Phenyl Methyl Siloxane) (manufactured by Hewlett-Packard Company)
Split ratio: 1/50
Flow rate: 1.0 mL / min
Temperature rise profile: 40 ° C. (3 min) → Temperature increase rate: 10 ° C./min→250° C. (5 min)
[MS]
Apparatus: 5973 Mass Selective Detector (manufactured by Hewlett-Packard Company)
Ionization method: EI
Mass range: 50 to 800 m / z
For the analysis of the crosslinking state, the “Polymer Analysis Handbook” (Japan Analytical Chemistry Society Polymer Analysis Research Meeting (ed)) was referred to.

(Examples 4 , 7, and 12, Reference Examples 1 to 3, 5, 6, 8 to 11 )
Charge rolls 2 to 12 were obtained in the same manner as Reference Example 1 except that the mixtures having the compositions shown in Examples 4, 7 , and 12 and Reference Examples 1 to 3, 5 , 6, and 8 to 11 in Table 4 were used. It was.

(Comparative Examples 1-5)
Charging rolls 13 to 17 were obtained in the same manner as in Reference Example 1 except that the mixtures having the compositions shown in Comparative Examples 1 to 5 in Table 5 were used.

In addition, the material used by each Example and the comparative example is as follows.
Toresin EF30T (N-methoxymethylated nylon 6, weight average molecular weight approximately 60,000, manufactured by Nagase ChemteX)
Toresin F30K (N-methoxymethylated nylon 6, weight average molecular weight of about 25,000, manufactured by Nagase ChemteX)
Amilan CM8000 (nylon 6 / nylon 6,6 / nylon 6,10 / nylon 12 copolymer nylon, weight average molecular weight about 30,000, manufactured by Toray)
Epoxy resin Denacol EX-212L (aliphatic, manufactured by Nagase ChemteX)
Epoxy resin Adeka Resin EP4100E (aromatic, structural bisphenol A type, manufactured by ADEKA)
Isocyanate resin Sumidur BL3175 (aliphatic, structural hexamethylene diisocyanate type, made by Sumika Bayer Urethane)
Isocyanate resin Sumidur BL1100 (aromatic, structural tolylene diisocyanate type, made by Sumika Bayer Urethane)
Carbon black (product name MONACH1000, manufactured by Cabot)
Tin oxide (product name SN-100P, manufactured by Ishihara Sangyo)
Epoxy resin curing agent (Product name Adeka Hardener EH3636AS, manufactured by ADEKA)

<Evaluation of charging roll>
The charging rolls obtained in each of the examples and comparative examples were evaluated for durability evaluation, image quality evaluation, storage evaluation, and crack generation. The results are shown in Tables 4 and 5.

[Durability evaluation and image quality evaluation]
The charging roll is mounted on a drum cartridge of DocuCenterColor400CP, and 50,000 sheets of A4 paper is printed (50% halftone images are printed at 10 ° C. and 15% RH) at 50% with DocuCenterColor400CP. Image disturbance when a halftone image was printed was determined according to the following criteria.
a: There is no image disturbance b: There is an image disturbance, but it is a minor and no problem level c: There is an image distortion part d: Most of the image distortion occurs

[Storage evaluation]
A drum cartridge equipped with a charging roll was evaluated for storage at 45 ° C. and 90% RH for 7 days. Then, the drum cartridge was installed in the DocuCentreColor400CP, and a 50% halftone image on A4 paper in an environment of 10 ° C. and 15% RH. The presence or absence of white streak defects in the image when printing was determined based on the following criteria.
A: There is no image defect at the contact position of the charging roll with the photosensitive member B: Minor white streaks occur at the contact position of the charging roll with the photosensitive member, but no problem C: At the contact position of the charging roll with the photosensitive member Clear white streaks appear

[Crack generation]
The occurrence of cracks was visually evaluated according to the following criteria.
◎: No crack is generated ○: A slight crack is generated in a small part of the charging roll, but there is no problem △: A crack is generated in a part of the charging roll ×: A crack is generated in almost the entire surface of the charging roll

Thus, by using the charging roller of Example 4,7,12, were able to suppress image defects caused such as cracks of the charging member in the case of long-term use.

It is a schematic diagram which shows an example of the charging device which concerns on embodiment of this invention. 1 is a schematic diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. It is a schematic diagram which shows the other example of the image forming apparatus which concerns on embodiment of this invention. It is a schematic diagram which shows the other example of the image forming apparatus which concerns on embodiment of this invention. It is a schematic diagram which shows the other example of the image forming apparatus which concerns on embodiment of this invention. 1 is a schematic cross-sectional view illustrating an example of an electrophotographic photoreceptor according to an embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing another example of an electrophotographic photosensitive member according to an embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing another example of an electrophotographic photosensitive member according to an embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing another example of an electrophotographic photosensitive member according to an embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing another example of an electrophotographic photosensitive member according to an embodiment of the present invention. It is a schematic diagram for explaining the arrangement position of the charging member cleaning roll and the charging roll.

Explanation of symbols

1 electrophotographic photoreceptor, 2 conductive support, 3 photosensitive layer, 4 undercoat layer, 5 charge generation layer, 6 charge transport layer, 7 protective layer, 8 single-layer type photosensitive layer, 10 cleaning roll, 12 charging roll, 14 outermost layer, 20 process cartridge, 21 charging device, 25 developing device, 25Y, 25M, 25C, 25K developing device, 26 developing roller, 27 cleaning device, 27a fibrous member, 27b cleaning blade, 29 fibrous member, 30 exposure Device, 31 lubricant supply device, 40 transfer device, 42 transfer device, 44 fixing device, 50 intermediate transfer member, 51, 53, 55, 65 roller, 52 intermediate transfer belt, 60 tray, 61 take-out roller, 63 roller pair, 100, 110, 120, 130 Image forming apparatus.

Claims (5)

For charging the surface of the image carrier provided in the image forming apparatus,
A base material, and an outermost layer provided on the base material and in contact with the image carrier,
The outermost layer includes a polyamide resin crosslinked with at least one of an epoxy resin containing an aromatic group and an isocyanate resin containing an aromatic group, and the degree of crosslinking is 90 % or more. Element. For charging the surface of the image carrier provided in the image forming apparatus,
A base material, and an outermost layer provided on the base material and in contact with the image carrier,
The charging member , wherein the outermost layer includes a polyamide resin crosslinked with an epoxy resin containing an aromatic group, and has a crosslinking degree of 90% or more .   A charging device comprising the charging member according to claim 1.   A process cartridge comprising an image carrier and the charging member according to claim 1.   An image carrier, a charging member according to claim 1, latent image forming means for forming a latent image on the surface of the image carrier, and a latent image formed on the surface of the image carrier with toner. An image forming apparatus comprising: a developing unit that develops and forms a toner image.