JP5609534B2 - Organic photoreceptor - Google Patents

Description

  The present invention relates to an organic photoreceptor used in an electrophotographic image forming apparatus.

  In general, a photoreceptor used in an electrophotographic image forming apparatus is repeatedly subjected to a series of image forming processes including a charging process, an exposure process, a developing process, a transfer process, a cleaning process, and a charge eliminating process. The electrostatic latent image formed by the charging process and the exposure process is visualized by a developer containing toner to form a toner image. This toner image is transferred to an image support such as paper by a transfer process. However, a part of the toner remains on the photoreceptor without being transferred to the image support. This residual toner is removed in a cleaning step in order to form a high-quality image in the next image forming process. Examples of the cleaning means used in this cleaning step include a fur brush, a magnetic brush, and a cleaning blade, but a cleaning blade is widely used from the viewpoint of cleaning accuracy and apparatus configuration.

  The cleaning blade is composed of an elastic member such as a plate-like polyurethane provided on a support base material, and is pressed against the surface of the photoreceptor. In addition, the contact form of the cleaning blade to the photoconductor includes a counter direction and a trading direction with respect to the rotation direction of the photoconductor. From the viewpoint of cleaning accuracy, the counter direction is the mainstream. ing.

Conventionally, as a photoreceptor, for example, zinc oxide (ZnO), cadmium sulfide (CdS), cadmium selenide (CdSe), amorphous selenium-based (a-Se, a-Se-Te, a-As ₂ Se ₃ ), etc. In recent years, the photosensitive layer has many advantages such as being easy to fabricate, capable of high sensitivity design, low cost, and non-polluting. Therefore, an organic photoreceptor having an organic compound in the photosensitive layer has become the mainstream.

  Such an organic photoreceptor is generally soft because the surface layer is mainly composed of a low molecular charge transport material and an inert polymer, and when used repeatedly in an image forming process, it depends on a development process and a cleaning process. Wear is likely to occur due to mechanical loads. Such wear of the organic photoconductor causes deterioration of electrical characteristics such as deterioration of sensitivity and chargeability, and as a result, a decrease in image density and background contamination occur to form a high-quality image. There is a problem that you can not. Further, there is a problem that due to the abrasion of the organic photoconductor, streaky stains, that is, a so-called toner slipping phenomenon occurs due to poor cleaning of the organic photoconductor, and a high-quality image cannot be formed.

In order to solve such a problem, a technique for curing the surface of the organic photoreceptor, a technique for providing a protective layer containing a filler on the surface of the organic photoreceptor, and the like have been proposed (for example, see Patent Documents 1 and 2). This improves the durability of the organic photoreceptor, such as wear resistance and scratch resistance.
However, as the wear resistance of the organic photoreceptor increases, there is a problem that chattering and peeling of the cleaning blade occur in the cleaning process.
Here, chatter of the cleaning blade refers to a phenomenon in which the cleaning blade vibrates due to an increase in frictional resistance between the cleaning blade and the surface of the organic photoconductor. In contrast, the cleaning blade is reversed.

Therefore, Patent Document 3 proposes a method in which reactive silicone oil is added to the surface layer of the organic photoreceptor in order to have high durability and suppress the occurrence of chatter and creaking of the cleaning blade.
However, such methods tend to cause poor curing in the surface layer. As a result, sufficient durability cannot be obtained, and it is not sufficient to suppress chattering and creaking of the cleaning blade. .

  Further, due to such a curing failure in the surface layer, there is a problem that ozone and nitrogen oxides are likely to adhere on the surface of the photoreceptor, and image defects such as image blur and image flow occur.

Japanese Patent Laid-Open No. 11-95474 JP 2008-96528 A JP 2010-107696 A

  The present invention has been made on the basis of the circumstances as described above, and its purpose is to have high durability, to suppress the occurrence of chattering and peeling of the cleaning blade, and to generate ozone and nitrogen oxides. It is an object of the present invention to provide an organic photoreceptor capable of forming a high-quality image free from image blur and the like accompanying the above.

The organic photoreceptor of the present invention is an organic photoreceptor in which an organic photosensitive layer and a protective layer are laminated in this order on a conductive support.
The protective layer is made of a cured resin obtained by polymerizing a radical polymerizable monomer in the presence of a mercapto-modified silicone oil ;
The cured resin constituting the protective layer is obtained by adding 0.1 to 4 parts by mass of mercapto-modified silicone oil to 100 parts by mass of the radical polymerizable monomer .

  In the organophotoreceptor of the present invention, the protective layer preferably contains metal oxide fine particles.

According to the organic photoreceptor of the present invention, the protective layer constituting the organic photoreceptor is made of a cured resin obtained by polymerizing a radical polymerizable monomer in the presence of a mercapto-modified silicone oil. In addition, it has high durability, suppresses chattering and creaking of the cleaning blade, and can form a high-quality image free from image blur due to generation of ozone and nitrogen oxides.
The reason why such an effect is achieved is considered as follows.
That is, the carbon radical generated in the polymerization reaction of the radical polymerizable monomer reacts with oxygen in the air to generate a peroxy radical. Usually, when this peroxy radical is generated, the polymerization reaction is stopped and the crosslinking density does not increase, so that sufficient curing is not performed. Therefore, in the protective layer constituting the organic photoreceptor of the present invention, the cured resin constituting the protective layer is obtained by polymerizing a radical polymerizable monomer in the presence of mercapto-modified silicone oil. As a result, the peroxy radical generated in the polymerization reaction of the radical polymerizable monomer draws out the hydrogen of the mercapto group in the mercapto-modified silicone oil and becomes an active radical, so that the polymerization reaction is continued. Thereby, it is considered that an organic photoreceptor having a high crosslinking density and a sufficient curing reaction is performed, and as a result, a high durability is obtained. In addition, since silicone oil generally has the property of being unevenly distributed near the surface, this property is used to synthesize mercapto-modified silicone oil for synthesizing a cured resin that forms a protective layer, which is the outermost surface that is likely to cause poor curing. It is considered that an organic photoreceptor having a high durability can be obtained by effectively performing a curing reaction. Further, it is considered that high lubricity is obtained on the surface of the protective layer due to the action of the mercapto-modified silicone oil remaining in the cured resin constituting the protective layer, and the chattering of the cleaning blade and the occurrence of peeling are suppressed.
In addition, it is considered that when a sufficient curing reaction is performed, the unreacted residue of the radical polymerizable monomer, which is considered to be a cause of image blurring, is reduced, and the occurrence of image blurring is suppressed.

  Hereinafter, the present invention will be described in detail.

<Organic photoconductor>
The organic photoreceptor of the present invention is obtained by laminating an organic photosensitive layer and a protective layer in this order on a conductive support.
The organophotoreceptor of the present invention is not particularly limited as long as it has the above layer structure, and specifically includes the following layer structures (1) and (2).
(1) A layer structure in which a charge generation layer, a charge transport layer, and a protective layer are laminated in this order as an intermediate layer and an organic photosensitive layer on a conductive support.
(2) A layer structure in which an intermediate layer, a single layer containing a charge generation material and a charge transport material as an organic photosensitive layer, and a protective layer are laminated in this order on a conductive support.

  In the present invention, the organic photoreceptor means a structure in which at least one of a charge generation function and a charge transport function essential to the configuration of the electrophotographic photoreceptor is exhibited by an organic compound. Includes all known organic photoreceptors such as a photoreceptor having a photosensitive layer composed of a generating material or an organic charge transport material, and a photoreceptor having a photosensitive layer in which a charge generating function and a charge transport function are composed of a polymer complex Say.

[Protective layer]
The protective layer constituting the organic photoreceptor of the present invention is made of a cured resin obtained by polymerizing a radical polymerizable monomer in the presence of a mercapto-modified silicone oil. This curable resin is obtained by, for example, irradiating an active ray such as an ultraviolet ray or an electron beam to polymerize a radical polymerizable monomer (a curing reaction).

(Radically polymerizable monomer)
Examples of the radical polymerizable monomer for forming the cured resin include styrene monomers, acrylic monomers, methacrylic monomers, vinyl toluene monomers, vinyl acetate monomers, N-vinyl pyrrolidone monomers, and the like. These radically polymerizable monomers can be used alone or in combination of two or more.

Since the radical polymerizable monomer can be cured with a small amount of light or in a short time, it is preferable that the monomer has an acryloyl group (CH ₂ ═CHCO—) or a methacryloyl group (CH ₂ ═CCH ₃ CO—). .

  Specific examples of the radical polymerizable monomer having an acryloyl group or a methacryloyl group include those represented by the following formulas (Ac-1) to (Ac-41) and the following formulas (Mc-1) to (Mc41). . The number of Ac groups or Mc groups shown below is the number of acryloyl groups or methacryloyl groups.

  In the above formulas (Ac-1) to (Ac-41), R is an acryloyl group represented by the following formula (1).

  However, in said formula (Mc-1)-formula (Mc-41), R 'is a methacryloyl group shown in following formula (2).

  It is preferable to use a radically polymerizable monomer having 3 or more functional groups (reactive groups). In addition, radically polymerizable monomers can be used in combination of two or more. In this case, it is preferable to use 50% by mass or more of those having 3 or more functional groups.

  Specific examples of the method of polymerizing the radical polymerizable monomer include a method of reacting by electron beam cleavage, a method of adding a polymerization initiator and reacting with light, heat, and the like. As the polymerization initiator, either a photopolymerization initiator or a thermal polymerization initiator can be used. Moreover, a photoinitiator and a thermal polymerization initiator can also be used together.

  Examples of the thermal polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylazobisvaleronyl), 2,2′-azobis (2-methyl). Azo compounds such as butyronitrile); benzoyl peroxide (BPO), di-tert-butyl hydroperoxide, tert-butyl hydroperoxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl peroxide, lauroyl peroxide, etc. And peroxides.

  Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1 (“Irgacure 369” manufactured by BASF Japan Ltd.), 2-hydroxy-2 -Methyl-1-phenylpropan-1-one, 2-methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) Acetophenone or ketal photoinitiators such as oximes; benzoin, benzoin methyl ether Benzoin ether photopolymerization initiators such as benzoin ethyl ether, benzoin isobutyl ether, benzoin isopropyl ether; benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoyl Benzophenone photopolymerization initiators such as phenyl ether, acrylated benzophenone, 1,4-benzoylbenzene; 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4- Examples thereof include thioxanthone photopolymerization initiators such as dichlorothioxanthone.

  Examples of other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, and bis (2,4,6-trimethylbenzoyl). Phenylphosphine oxide (“Irgacure 819” manufactured by BASF Japan Ltd.), bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10-phenanthrene, acridine Compounds, triazine compounds, imidazole compounds and the like. In addition, a photopolymerization accelerator having a photopolymerization promoting effect can be used alone or in combination with the photopolymerization initiator. Examples of the photopolymerization accelerator include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, and 4,4′-dimethylaminobenzophenone. Etc.

  The polymerization initiator used in the present invention is preferably a photopolymerization initiator, preferably an alkylphenone compound or a phosphine oxide compound, more preferably a polymerization initiator having an α-hydroxyacetophenone structure or an acylphosphine oxide structure. Agents are preferred.

  It is preferable that the addition amount of a polymerization initiator is 0.1-30 mass parts with respect to 100 mass parts of radically polymerizable monomers, More preferably, it is 0.5-10 mass parts.

(Mercapto-modified silicone oil)
The mercapto-modified silicone oil used in the present invention is obtained by modifying a polymer compound having a siloxane bond (Si—O—Si) structure in the main skeleton with a mercapto group. Examples thereof include 1) and the formula (O-2).

[In the above formula (O-1), R ¹ is a group represented by the following formula (3), p represents an integer of 8 to 1500, and q represents an integer of 1 to 30. ]

[In said Formula (3), r shows the integer of 1-8. ]

[In the formula ^(O-2), R 2 is a group represented by the following formula (4), s is an integer of 1 to 1,000. ]

[In said formula (4), t shows the integer of 1-8. ]

The functional group equivalent of the mercapto-modified silicone oil is preferably 1500 to 35000 g / mol, more preferably 1500 to 10000 g / mol.
When the functional group equivalent of the mercapto-modified silicone oil is excessive, the number of mercapto groups in the mercapto-modified silicone oil is small, so that sufficient curing can be achieved in the polymerization reaction of the radical polymerizable monomer for forming the protective layer. As a result, there is a possibility that high durability cannot be obtained for the organic photoreceptor. On the other hand, when the functional group equivalent of the mercapto-modified silicone oil is too small, the number of mercapto groups in the mercapto-modified silicone oil is large, and thus there is a possibility that high lubricity cannot be sufficiently imparted to the surface of the protective layer. .
The functional group equivalent means a value obtained by dividing the total molecular weight by the number of functional groups (mercapto groups).

  Mercapto-modified silicone oil can be produced by a known method. For example, trimethylsiloxy-terminated polydimethylsiloxane, octamethylcyclotetrasiloxane and methylmercaptopropylpolysiloxane are used as raw materials and polymerized at high temperature using a basic catalyst. And by removing low-molecular-weight siloxane by a substitution high temperature vacuum stripping method. The molecular weight can be adjusted by arbitrarily adjusting the amount of the raw material added.

(Metal oxide fine particles)
The protective layer according to the present invention preferably contains metal oxide fine particles. When the protective layer contains metal oxide fine particles, the organophotoreceptor has higher durability.
Such metal oxide fine particles may be metal oxide particles including transition metals. For example, silica (silicon oxide), magnesium oxide, zinc oxide, lead oxide, alumina (aluminum oxide), tin oxide, oxide Metal oxides such as tantalum, indium oxide, bismuth oxide, yttrium oxide, cobalt oxide, copper oxide, manganese oxide, selenium oxide, iron oxide, zirconium oxide, germanium oxide, tin oxide, titanium dioxide, niobium oxide, molybdenum oxide, vanadium oxide Among these, fine particles of alumina (Al ₂ O ₃ ), tin oxide (SnO ₂ ), and titanium dioxide (TiO ₂ ) are preferable, and alumina and tin oxide are more preferable.

The number average primary particle size of the metal oxide fine particles is preferably in the range of 1 to 300 nm, more preferably 3 to 100 nm.
In the present invention, the number average primary particle size of the metal oxide fine particles is measured as follows.
That is, a 10000 times magnified photograph was taken with a scanning electron microscope “JSM-7500F” (manufactured by JEOL Ltd.), and a photographic image (excluding aggregated particles) obtained by randomly capturing 300 metal oxide fine particles with a scanner. Calculation is performed using an automatic image processing analysis apparatus “LUZEX AP” (software version Ver. 1.32, manufactured by Nireco).

The content of the metal oxide fine particles is preferably 20 to 80% by mass, and more preferably 40 to 70% by mass with respect to the entire protective layer.
When the content of the metal oxide fine particles is too small, the electrical resistance of the protective layer becomes low, and it may not be possible to prevent an increase in residual potential and occurrence of fog. On the other hand, when the content of the metal oxide fine particles is excessive, the protective layer may not have good film formability, and it may not be possible to prevent deterioration of charging performance or pinholes.

Moreover, it is preferable that metal oxide microparticles | fine-particles are surface-treated with a surface treating agent. As the surface treatment agent, a silane coupling agent having a reactive organic group (hereinafter also referred to as “reactive organic group-containing silane coupling agent”) is preferably used.
Since the metal oxide fine particles are surface-treated with a reactive organic group-containing silane coupling agent, the bond with the radical polymerizable monomer becomes strong, and the protective layer has higher durability. .

  The reactive organic group-containing silane coupling agent is not particularly limited as long as it has reactivity with the hydroxyl group and the like present on the surface of the metal oxide fine particles. Specifically, the reactive organic group-containing silane coupling agent is represented by the following formulas (S-1) to ( S-36).

Formula _{(S-1): CH 2} = CHSi (CH 3) (OCH 3) 2
Formula _{(S-2): CH 2} = CHSi (OCH 3) 3
Formula (S-3): CH ₂ = CHSiCl ₃
Formula _{(S-4): CH 2} = CHCOO (CH 2) 2 Si (CH 3) (OCH 3) 2
Formula _{(S-5): CH 2} = CHCOO (CH 2) 2 Si (OCH 3) 3
Formula _{(S-6): CH 2} = CHCOO (CH 2) 2 Si (OC 2 H 5) (OCH 3) 2
Formula _{(S-7): CH 2} = CHCOO (CH 2) 3 Si (OCH 3) 3
Formula _{(S-8): CH 2} = CHCOO (CH 2) 2 Si (CH 3) Cl 2
Formula _{(S-9): CH 2} = CHCOO (CH 2) 2 SiCl 3
Formula _{(S-10): CH 2} = CHCOO (CH 2) 3 Si (CH 3) Cl 2
Formula (S-11): CH ₂ = CHCOO (CH ₂ ) ₃ SiCl ₃
Formula _{(S-12): CH 2} = C (CH 3) COO (CH 2) 2 Si (CH 3) (OCH 3) 2
Formula _{(S-13): CH 2} = C (CH 3) COO (CH 2) 2 Si (OCH 3) 3
Formula _{(S-14): CH 2} = C (CH 3) COO (CH 2) 3 Si (CH 3) (OCH 3) 2
Formula _{(S-15): CH 2} = C (CH 3) COO (CH 2) 3 Si (OCH 3) 3
Formula _{(S-16): CH 2} = C (CH 3) COO (CH 2) 2 Si (CH 3) Cl 2
Formula _{(S-17): CH 2} = C (CH 3) COO (CH 2) 2 SiCl 3
Formula _{(S-18): CH 2} = C (CH 3) COO (CH 2) 3 Si (CH 3) Cl 2
Formula _{(S-19): CH 2} = C (CH 3) COO (CH 2) 3 SiCl 3
Formula _{(S-20): CH 2} = CHSi (C 2 H 5) (OCH 3) 2
Formula _{(S-21): CH 2} = C (CH 3) Si (OCH 3) 3
Formula _{(S-22): CH 2} = C (CH 3) Si (OC 2 H 5) 3
Formula _{(S-23): CH 2} = CHSi (OCH 3) 3
Formula _{(S-24): CH 2} = C (CH 3) Si (CH 3) (OCH 3) 2
Formula _{(S-25): CH 2} = CHSi (CH 3) Cl 2
Formula _{(S-26): CH 2} = CHCOOSi (OCH 3) 3
Formula _{(S-27): CH 2} = CHCOOSi (OC 2 H 5) 3
Formula _{(S-28): CH 2} = C (CH 3) COOSi (OCH 3) 3
Formula _{(S-29): CH 2} = C (CH 3) COOSi (OC 2 H 5) 3
Formula _{(S-30): CH 2} = C (CH 3) COO (CH 2) 3 Si (OC 2 H 5) 3
Formula _{(S-31): CH 2} = CHCOO (CH 2) 2 Si (CH 3) 2 (OCH 3)
Formula _{(S-32): CH 2} = CHCOO (CH 2) 2 Si (CH 3) (OCOCH 3) 2
Formula _{(S-33): CH 2} = CHCOO (CH 2) 2 Si (CH 3) (ONHCH 3) 2
Formula _{(S-34): CH 2} = CHCOO (CH 2) 2 Si (CH 3) (OC 6 H 5) 2
Formula _{(S-35): CH 2} = CHCOO (CH 2) 2 Si (C 10 H 21) (OCH 3) 2
Formula _{(S-36): CH 2} = CHCOO (CH 2) 2 Si (CH 2 C 6 H 5) (OCH 3) 2

Moreover, as a surface treating agent, the silane compound which has a reactive organic group which can be radically polymerized other than what is shown to the said Formula (S-1)-Formula (S-36) can be used.
These surface treatment agents can be used alone or in combination of two or more.

  The surface treatment method using a surface treatment agent for the metal oxide fine particles is not particularly limited, and wet treatment or dry treatment can be employed, but treatment using a wet media dispersion type apparatus is preferable.

Hereinafter, a surface treatment method using a wet media dispersion type apparatus will be specifically described.
That is, by subjecting a slurry (suspension of solid particles) containing metal oxide fine particles and a surface treatment agent to wet pulverization, the metal oxide fine particles are refined and the surface treatment of the metal oxide fine particles proceeds. After that, the surface-treated metal oxide fine particles are obtained by removing the solvent and pulverizing.

  In the surface treatment method as described above, the addition amount of the surface treatment agent is 0.1 to 100 parts by mass with respect to 100 parts by mass of the metal oxide fine particles, and the addition amount of the solvent is 100 parts by mass of the metal oxide fine particles. It is preferable that it is 50-5000 mass parts with respect to it.

Wet media dispersion type device is a device that crushes and disperses the aggregated particles of metal oxide by filling beads in the container as media and rotating the stirring disk mounted perpendicular to the rotation axis at high speed. The configuration is not particularly limited as long as the metal oxide fine particles can be sufficiently dispersed and surface-treated when the surface treatment is performed on the metal oxide fine particles. For example, vertical / horizontal, continuous Various forms such as a formula and a batch type can be adopted. Specifically, a sand mill, an ultra visco mill, a pearl mill, a glen mill, a dyno mill, an agitator mill, a dynamic mill, or the like can be used.
In these dispersion-type apparatuses, pulverization and dispersion are performed by impact crushing, friction, shearing, shear stress, and the like using a pulverizing medium (media) such as balls and beads.

  Examples of the beads used in the sand mill include grinding media made of glass, alumina, zircon, zirconia, steel, flint stone and the like, and those made of zirconia or zircon are particularly preferable. The size of the beads is usually about 1 to 2 mm in diameter, but in the present invention, about 0.1 to 1.0 mm is preferable.

  For example, stainless steel, nylon, and ceramic materials are used for the stirring disk and the inner wall of the container used in the wet media dispersion type apparatus, but ceramic materials such as zirconia or silicon carbide are particularly preferable.

  By the surface treatment with the surface treatment agent as described above, metal oxide fine particles having a reactive organic group capable of reacting with a reactive acryloyl group and a reactive methacryloyl group can be obtained.

The protective layer constituting the organophotoreceptor of the present invention can also be constituted by using a known resin together with a cured resin.
Examples of known resins include polyester resins, polycarbonate resins, polyurethane resins, acrylic resins, epoxy resins, silicone resins, alkyd resins, and the like.

Further, the protective layer constituting the organic photoreceptor of the present invention may contain lubricant particles, a charge transport material, an antioxidant and the like, if necessary.
Examples of the lubricant particles include fluorine atom-containing resin particles. Examples of the fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluorinated ethylene chloride resin, hexafluoroethylene chloride propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin, and these It is preferable to select one or two or more of these copolymer particles as appropriate, but tetrafluoroethylene resin particles and vinylidene fluoride resin particles are particularly preferable.

The content of the lubricant particles is preferably 0.1 to 20% by mass, more preferably 0.2 to 10% by mass with respect to the entire protective layer.
The number average primary particle size of the lubricant particles is preferably 0.01 to 1 μm, more preferably 0.05 to 0.5 μm.
In the present invention, the number average primary particle size of the lubricant particles is measured as follows.
In other words, a 10000x magnified photograph was taken with a scanning electron microscope "JSM-7500F" (manufactured by JEOL Ltd.), and a photographic image (excluding aggregated particles) obtained by randomly capturing 300 lubricant particles with a scanner was automatically displayed. Calculation is performed using a processing analysis apparatus “LUZEX AP” (software version Ver. 1.32, manufactured by Nireco).

  The molecular weight of the resin constituting the lubricant particles can be appropriately selected and is not particularly limited.

(Method for forming protective layer)
As a method for forming the protective layer, a radical polymerizable monomer and, if necessary, metal oxide fine particles are dissolved in a known solvent, and a dispersion is prepared, for example, using a disperse mat disperser. A mercapto-modified silicone oil is added to this dispersion to prepare a protective layer coating solution (coating solution preparing step), and this protective layer coating solution is applied onto the organic photosensitive layer to form a coating film (coating layer forming step). Thereafter, a method of natural drying or heat drying (drying step), and a polymerization / curing reaction (polymerization step) by irradiation with actinic rays is preferable.

  Examples of the solvent used for forming the protective layer include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol, benzyl alcohol, toluene, xylene, methylene chloride, and methyl ethyl ketone. , Cyclohexane, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine, diethylamine, and the like, but are not limited thereto.

In the coating solution preparation step, the content of mercapto-modified silicone oil with respect to the entire protective layer coating solution is preferably 50 to 5000 ppm.
Moreover, it is preferable that the addition amount of the mercapto modified silicone oil with respect to a radically polymerizable monomer is 0.1-4 mass parts with respect to 100 mass parts of radically polymerizable monomers.
When the addition amount of the mercapto-modified silicone oil is within the above range, a sufficient polymerization reaction promoting function in the polymerization reaction of the radical polymerizable monomer is achieved.

  Further, when metal oxide fine particles are contained in the protective layer, the addition amount of the metal oxide fine particles is preferably 20 to 400 parts by mass, more preferably 50 to 100 parts by mass with respect to 100 parts by mass of the radical polymerizable monomer. 300 parts by mass.

  In the coating film forming process, as a coating method of the protective layer coating solution, for example, a known method such as a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a blade coating method, a beam coating method, a slide hopper method, etc. Is mentioned.

In the polymerization process, for example, radicals are generated by irradiating the coating with actinic radiation to polymerize the radically polymerizable monomer, and at the same time, cure and cure by forming a cross-linking bond between the molecules and within the molecule. Resin is produced.
As the actinic ray, ultraviolet rays and electron beams are preferable, and ultraviolet rays are particularly preferable from the viewpoint of ease of use.

The ultraviolet light source is not particularly limited as long as it is a light source that generates ultraviolet light. Is mentioned.
Irradiation conditions vary depending on the type of each lamp, but the irradiation amount of active rays is usually 5 to 500 mJ / cm ² , preferably 5 to 100 mJ / cm ² . The power of the lamp is preferably 0.1 to 5 kW, more preferably 0.5 to 3 kW.

  As an electron beam source, there is no particular limitation on the electron beam irradiation apparatus, and generally, an electron beam accelerator for electron beam irradiation is a curtain beam type that is relatively inexpensive and can provide a large output. Used. The acceleration voltage of electron beam irradiation is preferably 100 to 300 kV. The absorbed dose is preferably 0.5 to 10 Mrad.

  The irradiation time for obtaining the necessary irradiation amount of active rays is preferably 0.1 second to 10 minutes, and more preferably 0.1 second to 5 minutes from the viewpoint of work efficiency.

  The drying step can be performed before and after irradiation with active rays and during irradiation with active rays, and the timing of drying can be appropriately selected by combining them.

  Although drying conditions can be suitably selected according to the kind of solvent, layer thickness, etc., it is preferable that drying temperature is room temperature-180 degreeC, for example, More preferably, it is 80-140 degreeC. The drying time is preferably, for example, 1 to 200 minutes, and more preferably 5 to 100 minutes.

  The thickness of the protective layer is preferably 0.2 to 10 μm, more preferably 0.5 to 6 μm.

[Conductive support]
The conductive support constituting the organic photoreceptor of the present invention is not particularly limited as long as it has conductivity. For example, a metal such as aluminum, copper, chromium, nickel, zinc, and stainless steel is used. Molded in drum or sheet form, laminated metal foil such as aluminum or copper on plastic film, deposited aluminum, indium oxide and tin oxide on plastic film, conductive material alone or with binder resin Examples include metals, plastic films, and papers that are coated to provide a conductive layer.

[Middle layer]
In the organic photoreceptor of the present invention, an intermediate layer having a barrier function and an adhesive function can be provided between the conductive support and the organic photosensitive layer. From the viewpoint of preventing various failures, it is preferable to provide such an intermediate layer.
This intermediate layer includes a binder resin (hereinafter also referred to as “binder resin for intermediate layer”), and various conductive fine particles and metal oxide fine particles (hereinafter referred to as “intermediate layer binder resin”) for the purpose of adjusting the resistance of the intermediate layer. It is also composed of inorganic fine particles such as “intermediate layer metal oxide fine particles”.

  Examples of the intermediate layer binder resin include casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide resin, polyurethane resin, gelatin and the like, and alcohol-soluble polyamide resins are preferable.

Examples of the metal oxide fine particles for the intermediate layer include metal oxide fine particles such as alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, and tin-doped indium oxide and antimony. Ultrafine particles such as doped tin oxide and zirconium oxide can also be used. These metal oxide fine particles for intermediate layer can be used alone or in combination of two or more. When two or more kinds of intermediate layer metal oxide fine particles are used in combination, the intermediate layer metal oxide fine particles may be in a solid solution state or in a fused state.
The number average primary particle size of such metal oxide fine particles for intermediate layer is preferably 0.3 μm or less, more preferably 0.1 μm or less.
In the present invention, the number average primary particle size of the intermediate layer metal oxide fine particles is measured as follows.
That is, a 10000 times magnified photograph was taken with a scanning electron microscope “JSM-7500F” (manufactured by JEOL Ltd.), and 300 photographic images of metal oxide particles for intermediate layer were randomly taken by a scanner (aggregated particles were Is excluded) using an automatic image processing analyzer “LUZEX AP” (software version Ver. 1.32, manufactured by Nireco).

[Method for forming intermediate layer]
The method for forming the intermediate layer is preferably a method in which an intermediate layer coating solution is prepared by dissolving the binder resin for the intermediate layer in a known solvent, and this intermediate layer coating solution is immersed and coated on a conductive support.

  As the solvent used for forming the intermediate layer, those in which inorganic fine particles are well dispersed and the polyamide resin is dissolved are preferable. Specifically, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t -Alcohols having 2 to 4 carbon atoms such as butanol and sec-butanol are particularly preferred from the viewpoints of solubility and applicability of the polyamide resin. Examples of the co-solvent that can be used in combination with the above-described solvent in order to improve the storage stability and the dispersibility of the inorganic fine particles include methanol, benzyl alcohol, toluene, methylene chloride, cyclohexanone, and tetrahydrofuran.

  The concentration of the intermediate layer binder resin is appropriately selected according to the thickness of the intermediate layer and the production rate.

  The means for dispersing the inorganic fine particles is not particularly limited, and examples thereof include a disperser such as an ultrasonic disperser, a ball mill, a sand grinder, and a homomixer.

  The amount of the inorganic fine particles added to the intermediate layer binder resin is preferably 20 to 400 parts by mass, more preferably 50 to 200 parts by mass with respect to 100 parts by mass of the intermediate layer binder resin.

  The method for drying the intermediate layer can be appropriately selected according to the type of solvent and the layer thickness, but a method by thermal drying is preferred.

  The thickness of the intermediate layer is preferably 0.1 to 15 μm, more preferably 0.3 to 10 μm.

[Organic photosensitive layer]
(Charge generation layer)
The charge generation layer in the organic photosensitive layer constituting the organic photoreceptor of the present invention is composed of a charge generation material and a binder resin (hereinafter also referred to as “binder resin for charge generation layer”). The charge generation material can be formed by dispersing and coating in a binder resin solution for a charge generation layer.

  Although it does not specifically limit as a charge generation substance, For example, azo raw materials, such as Sudan red and diane blue; Quinone pigments, such as pyrenequinone and anthanthrone; Quinocyanine pigment; Perylene pigment; Indigo pigments, such as indigo and thioindigo; And phthalocyanine pigments. These charge generation materials can be used alone or in combination of two or more.

  As the binder resin for the charge generation layer, known resins can be used. For example, polystyrene resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, Polyurethane resins, phenol resins, polyester resins, alkyd resins, polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of these resins (eg, vinyl chloride-vinyl acetate copolymer resins, chlorides) Vinyl-vinyl acetate-maleic anhydride copolymer resin), poly-vinylcarbazole resin, and the like, but are not limited thereto.

[Method for forming charge generation layer]
The charge generation layer is formed by preparing a charge generation layer coating solution by dispersing a charge generation material using a disperser in a solution obtained by dissolving a binder resin for a charge generation layer with a solvent. A method is preferred in which a coating film is formed by coating on a conductive support or an intermediate layer to a constant layer thickness with a coating machine, and then the coating film is dried.

  Examples of the solvent used for forming the charge generation layer include toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, methyl cellosolve, Examples include, but are not limited to, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine, diethylamine and the like.

  The means for dispersing the charge generating material is not particularly limited, and examples thereof include a dispersing machine such as an ultrasonic dispersing machine, a ball mill, a sand grinder, and a homomixer.

  The amount of the charge generation material added to the charge generation layer binder resin is preferably 1 to 600 parts by mass, and more preferably 50 to 500 parts by mass with respect to 100 parts by mass of the charge generation layer binder resin.

  The layer thickness of the charge generation layer varies depending on the characteristics of the charge generation material, the characteristics of the binder resin for the charge generation layer and the mixing ratio, but is preferably 0.01 to 5 μm, more preferably 0.05 to 3 μm. is there. It should be noted that the charge generation layer coating liquid can prevent the occurrence of image defects by filtering foreign matter and aggregates before coating. The pigment can also be formed by vacuum deposition.

(Charge transport layer)
The charge transport layer in the organic photosensitive layer constituting the organic photoreceptor of the present invention comprises a charge transport material (CTM) and a binder resin (hereinafter also referred to as “binder resin for charge transport layer”). The transport layer can be formed by dissolving and coating a charge transport material in a binder resin solution for a charge transport layer.

  Examples of charge transport materials include carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds, pyrazolines. Compound, oxazolone derivative, benzimidazole derivative, quinazoline derivative, benzofuran derivative, acridine derivative, phenazine derivative, aminostilbene derivative, triarylamine derivative, phenylenediamine derivative, stilbene derivative, benzidine derivative, poly-N-vinylcarbazole, poly-1 -Vinylpyrene, poly-9-vinylanthracene, triphenylamine derivatives and the like. These charge transport materials can be used alone or in combination of two or more.

  As the binder resin for the charge transport layer, a known resin can be used. Polycarbonate resin, polyacrylate resin, polyester resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polymethacrylate resin, styrene-methacrylic acid Examples include ester copolymer resins, and polycarbonate resins are preferred. Furthermore, bisphenol A (BPA), bisphenol Z (BPZ), dimethyl BPA, BPA-dimethyl BPA copolymer and the like are preferable in terms of crack resistance, wear resistance, and charging characteristics.

(Method for forming charge transport layer)
The charge transport layer is formed by dissolving a charge transport layer binder resin and a charge transport material to prepare a charge transport layer coating solution, and this charge transport layer coating solution is applied on the charge generation layer to a constant layer thickness by a coating machine. A method is preferred in which a coating film is formed by coating on the substrate and the coating film is dried.

  Examples of the solvent used for forming the charge transport layer include toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, tetrahydrofuran, 1 , 4-dioxane, 1,3-dioxolane, pyridine, diethylamine and the like, but are not limited thereto.

  The amount of the charge transport material added to the charge transport layer binder resin is preferably 10 to 500 parts by weight, more preferably 20 to 100 parts by weight, based on 100 parts by weight of the charge transport layer binder resin.

  The layer thickness of the charge transport layer varies depending on the characteristics of the charge transport material, the characteristics of the binder resin for charge transport layer and the mixing ratio, but is preferably 5 to 40 μm, more preferably 10 to 30 μm.

  The charge transport layer may contain an antioxidant, an electronic conductive agent, a stabilizer and the like as necessary. Examples of the antioxidant include those described in Japanese Patent Application No. 11-200135, and examples of the electronic conductive agent include those described in JP-A Nos. 50-137543 and 58-76483.

[Image forming apparatus]
The organic photoreceptor of the present invention can be used in various known electrophotographic image forming apparatuses such as a monochrome image forming apparatus and a full color image forming apparatus.
The image forming apparatus in which the organic photoreceptor of the present invention is used includes, for example, a charging unit that applies a uniform charging potential on the organic photoreceptor, and an electrostatic latent image on the organic photoreceptor to which the uniform charging potential is applied. An exposure unit for forming, a developing unit for developing the electrostatic latent image with toner into a toner image, a transfer unit for transferring the toner image onto the transfer material, and a fixing for fixing the toner image on the transfer material. Means and a cleaning means for removing the toner remaining on the organic photoreceptor.
A cleaning blade is preferably used as the cleaning means in the image forming apparatus using the organic photoreceptor of the present invention.

〔toner〕
The electrostatic latent image formed on the organic photoreceptor of the present invention is visualized as a toner image by development. The toner used for this development may be a pulverized toner or a polymerized toner, but a polymerized toner prepared by a polymerization method is preferred from the viewpoint of obtaining a stable particle size distribution.

  Polymerized toner is formed by the formation of a binder resin (hereinafter also referred to as “binder resin for toner”) and the shape of the toner by polymerization reaction of the raw material monomer of the toner binder resin and, if necessary, subsequent chemical treatment. Specifically, it means a material formed through a polymerization reaction such as suspension polymerization or emulsion polymerization and, if necessary, a step of fusing the particles thereafter.

The particle diameter of the toner particles constituting the toner is preferably 2 to 9 μm, more preferably 3 to 7 μm in terms of volume average particle diameter (Dv50).
When the particle diameter of the toner particles is in the above range, the resolution of the formed image can be increased. Furthermore, although the toner particles have a small particle size, the abundance of fine toner particles can be reduced, the dot image reproducibility is improved over a long period of time, and a stable image with good sharpness. Can be formed.
The volume average particle diameter (Dv50) of the toner particles is measured and calculated using a measuring device in which a computer system for data processing (manufactured by Beckman Coulter) is connected to “Multisizer 3” (manufactured by Beckman Coulter). Is.

(Developer)
The toner according to the present invention may be used as a one-component developer or a two-component developer.

  When used as a one-component developer, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner can be used. can do.

  Further, it can be mixed with a carrier and used as a two-component developer. In this case, conventionally known materials such as metals such as iron, ferrite, and magnetite, and alloys of these metals with metals such as aluminum and lead can be used as the magnetic particles of the carrier. Ferrite particles are particularly preferable.

The magnetic particles constituting the carrier preferably have a volume average particle size (Dv50) of 15 to 100 μm, more preferably 25 to 80 μm.
In the present invention, the volume average particle diameter (Dv50) of the magnetic particles is measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser. is there.

  The carrier is preferably a resin-coated type in which magnetic particles are further coated with a resin, or a so-called resin-dispersed type in which magnetic particles are dispersed in a resin. The coating resin for constituting the resin-coated carrier is not particularly limited. For example, olefin resin, styrene resin, styrene-acrylic resin, silicone resin, ester resin, fluorine-containing resin Examples thereof include polymer resins. In addition, the dispersing resin for constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, styrene-acrylic resin, polyester resin, fluorine resin, phenol resin Etc.

  According to the present invention, the silicone oil used for imparting high lubricity to the surface of the protective layer is made mercapto-modified, so that the permeate produced in the polymerization reaction of the radically polymerizable monomer for forming the protective layer. Since the oxy radicals extract the hydrogen of the mercapto group in the mercapto-modified silicone oil and become active radicals, the polymerization reaction is continued, so that sufficient curing is performed, resulting in high durability and a cleaning blade An organic photoconductor that suppresses the occurrence of chattering and peeling is obtained, and this organic photoconductor can form a high-quality image free from image blur caused by the generation of ozone or nitrogen oxides. it can.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

[Organic photoconductor production example 1]
(1) Production of conductive support The surface of a drum-like aluminum support was cut to produce a conductive support [1] having a surface roughness Rz = 1.5 (μm).

(2) Formation of the intermediate layer The following raw material was used as a disperser, and a sand mill was used for 10 hours of dispersion to prepare an intermediate layer coating solution [1].
-Binder resin: Polyamide resin "X1010" (manufactured by Daicel Degussa) 1 part by mass-Metal oxide fine particles: Titanium oxide "SMT500SAS" (manufactured by Teica) (number average primary particle size: 0.035 μm) 1.1 parts by mass -Solvent: 20 parts by mass of ethanol On the conductive support [1], this intermediate layer coating solution [1] is applied by a dip coating method, dried at 110 ° C. for 20 minutes, and an intermediate layer [1 μm in thickness of 2 μm] ] Was formed.

(3) Formation of organic photosensitive layer (formation of charge generation layer)
Dispersion for 10 hours was performed using a sand mill with the following raw materials as a disperser to prepare a charge generation layer coating solution [1].
Charge generating material: titanyl phthalocyanine pigment (having a maximum diffraction peak at a position of 5 at least 27.3 ° by Cu-Kα characteristic X-ray diffraction spectrum measurement) 20 parts by mass Binder resin: polyvinyl butyral resin “# 6000-C (Electric Chemical Industry Co., Ltd.)
10 parts by mass / solvent: 700 parts by mass of t-butyl acetate / solvent: 300 parts by mass of 4-methoxy-4-methyl-2-pentanone On the intermediate layer [1], the charge generation layer coating solution [1] was added. The charge generation layer [1] having a layer thickness of 0.3 μm was formed by dip coating.

(Formation of charge transport layer)
The following raw materials were mixed and dissolved to prepare a charge transport layer coating solution [1].
Charge transport material: 150 parts by mass of a compound represented by the following formula (A) Binder resin: 300 parts by mass of a polycarbonate resin “Z300” (manufactured by Mitsubishi Gas Chemical) ・ Antioxidant: “Irganox 1010” (manufactured by Ciba Geigy Japan) 6 Mass parts / Solvent: Toluene / tetrahydrofuran = 1/9% by volume 2000 parts by mass Leveling agent: Silicone oil “KF-54” (manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by mass On the charge generation layer [1], this charge transport The layer coating solution [1] was applied by a dip coating method and dried at 120 ° C. for 70 minutes to form a charge transport layer [1] having a layer thickness of 20 μm.

(4) Formation of protective layer Disperse the following radical polymerizable monomer and solvent using a sand mill for 10 hours using a sand mill, then add the following mercapto-modified silicone oil and polymerization initiator, mix under light shielding, stir and dissolve A protective layer coating solution [1] was prepared (coating solution preparation step). During this process, the light shielding state was maintained.
Radical polymerizable monomer: Compound represented by formula (Mc-1) 100 parts by mass Solvent: 2-butanol 500 parts by mass Mercapto-modified silicone oil: Formula (O-1) above (where R ¹ is formula (3) In which r = 3, functional group equivalent = 1900] 0.6 parts by mass / polymerization initiator: “Irgacure 819” (manufactured by BASF Japan) 10 parts by mass The protective layer coating solution [1] is charged with the above charge. A coating film was formed on the transport layer [1] by using a circular slide hopper coating machine (coating film forming step). Then, it is dried at room temperature for 20 minutes (drying process), and irradiated for 1 minute while rotating at a position of 100 mm using a metal halide lamp (500 W) (polymerization process) to form a protective layer [1] having a layer thickness of 3 μm. An organic photoreceptor [1] was prepared.

[Production Examples 2 to 6 of an organic photoreceptor]
In Preparation Example 1 of the organic photoreceptor, (4) the radically polymerizable monomer in the formation of the protective layer was changed to the one shown in Table 1 and the addition amount, and the mercapto-modified silicone oil shown in Table 1 and the addition amount were changed. Organic photoreceptors [2] to [6] were prepared in the same manner except that the metal oxide fine particles shown in Table 1 were added to the protective layer coating solution [1].

[Organic photoconductor production example 7]
An organic photoreceptor [7] was prepared in the same manner except that (4) formation of the protective layer in Preparation Example 1 of the organic photoreceptor was changed to the following protective layer formation method.
(4) Formation of protective layer The following raw materials were mixed and dissolved to prepare a protective layer coating solution [7].
Binder resin: Polycarbonate resin “Z300” (Mitsubishi Gas Chemical Co., Ltd.) 100 parts by mass Solvent: Toluene / tetrahydrofuran = 1/9 vol% 500 parts by mass Mercapto-modified silicone oil: Formula (O-1) above Compound represented by r = 3, functional group equivalent = 1900] in formula (3) in R ¹ 0.6 parts by weight This protective layer coating solution [7] was applied to the charge transport layer [1] with a circle slide hopper. And dried at 120 ° C. for 70 minutes to form a protective layer [7] having a layer thickness of 3 μm, thereby preparing an organic photoreceptor [7].

[Production Example 8 of Organic Photoreceptor]
An organic photoreceptor [8] was prepared in the same manner as in Preparation Example 1 of the organic photoreceptor except that (4) the mercapto-modified silicone oil in the formation of the protective layer was changed to those shown in Table 1 and the amount added.

[Examples 1 to 3, Reference Examples 1 to 3, and Comparative Examples 1 and 2]
The organic photoreceptors [1] to [8] obtained as described above are mounted on a full-color image forming apparatus “bizhub PRO C6500” (manufactured by Konica Minolta Business Technologies, Inc .; using an exposure light of a semiconductor laser of 600 dpi and 780 nm). did. Since this full-color image forming apparatus has four sets of image forming units, the photoconductors of the respective image forming units are unified with the same type of photoconductor (for example, in the case of the organic photoconductor [1]). The following evaluations 1 to 3 were performed using four organic photoreceptors [1]. Each evaluation was performed after a press life test in which 500,000 sheets of A4 images with a YMCBk color printing ratio of 2.5% were printed on neutral paper of A4 size at a temperature of 30 ° C. and a humidity of 80% RH. The results are shown in Table 2.

[Evaluation 1: Image blur]
Immediately after the printing durability test, the main power of the image forming apparatus was turned off. Immediately after the main power supply was turned off and the main power supply was turned on and printing was possible, a halftone image (relative reflection density of 0.4 with a Macbeth densitometer) and a 6-dot grid image on the entire surface of neutral paper of A3 size immediately. And printed. The state of the printed image was visually observed and evaluated according to the following evaluation criteria.
-Evaluation criteria-
A: No blurring occurs in both halftone image and grid image (good)
B: A thin strip-like density decrease in the longitudinal direction of the photoreceptor is observed only in the halftone image (no problem in practical use)
C: Lattice image loss or line width narrowing due to image blurring (practical problem)

[Evaluation 2: Surface scratch]
The surface state of the organic photoreceptor before and after the printing durability test was visually observed, and the state of the scratch was evaluated according to the following evaluation criteria. It is assumed that the evaluated organic photoreceptor is installed in the cyan position.
-Evaluation criteria-
A: No surface damage after printing 500,000 sheets (good)
B: 1 to 5 surface scratches after printing 500,000 sheets (no practical problem)
C: 6 or more surface scratches after printing 500,000 sheets (practical problem)

[Evaluation 3: Filming phenomenon]
After the printing durability test, the image forming apparatus is left for 1 hour under an environmental condition of a temperature of 20 ° C. and a humidity of 50% RH, and then a halftone image is formed on neutral paper of A4 size. evaluated.
-Evaluation criteria-
A: Image noise due to filming phenomenon is not recognized (good)
B: Some image noise due to filming phenomenon is recognized (no problem in practical use)
C: Image noise caused by filming phenomenon (practical problem)

[Evaluation 4: Blade squeal]
After the printing endurance test, under the environmental conditions of temperature 10 ° C and humidity 15% RH, a printing endurance test was performed to print 200,000 sheets of A4 images with 2.5% YMCBk color coverage on neutral paper of A4 size. The squeal of the blade was evaluated according to the following evaluation criteria.
The squealing of the blade refers to a phenomenon in which abnormal noise is generated due to friction between the cleaning blade and the photosensitive member, and is a phenomenon caused by the occurrence of chatter of the cleaning blade.
-Evaluation criteria-
A: No blade squeaks until 200,000 sheets are printed (good)
B: Slight blade squeal when starting or stopping the photoreceptor (no problem in practical use)
C: Continuous blade squealing (practical problem)

Claims (2)

In an organic photoreceptor in which an organic photosensitive layer and a protective layer are laminated in this order on a conductive support,
The protective layer is made of a cured resin obtained by polymerizing a radical polymerizable monomer in the presence of a mercapto-modified silicone oil ;
An organic photoreceptor, wherein the cured resin constituting the protective layer is obtained by adding 0.1 to 4 parts by mass of a mercapto-modified silicone oil to 100 parts by mass of a radical polymerizable monomer .   The organophotoreceptor according to claim 1, wherein the protective layer contains metal oxide fine particles.