JP2017151365A - Electrophotographic photoreceptor and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor that can provide high durability and form a high resolution image even when being repeatedly used over a long period, and an image forming apparatus including the same.SOLUTION: The present electrophotographic photoreceptor is an electrophotographic photoreceptor that has an intermediate layer, a photosensitive layer, and a surface layer laminated in this order on a conductive substrate, where the surface layer is formed of a cured product of a composition that contains a monomer having an alkoxysilane structure, metal oxide fine particles including a reactive organic group reacting with a group other than a polymerizable reactive group in the monomer, and an electron transport agent. In the electrophotographic photoreceptor, the metal oxide fine particle is preferably formed of at least one selected from the group consisting of SnO, SiO, and AlO.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrophotographic photosensitive member used in an electrophotographic image forming process and an image forming apparatus including the same.

An electrophotographic photoreceptor (hereinafter, also simply referred to as “photoreceptor”) that constitutes an image forming apparatus such as an electrophotographic copying machine or printer has a long life and forms a high-resolution image. There is a need to be able to. In the photoconductor, the lifetime of the photoconductor is determined as the surface of the photoconductor is worn.
In recent years, as a photoreceptor that has excellent durability such as wear resistance and scratch resistance and has a long life, a photosensitive layer is laminated on a conductive support, and further, for example, a polymerizable monomer is formed on the photosensitive layer. A photoreceptor having a surface layer made of a cured product has been developed. A hole transport agent is added to the surface layer of such a cured product, and in image formation, residual negative charges located near the surface are erased by transporting holes from the conductive support to the surface layer side. (Cancel).

  On the other hand, in recent years, as a charging method for a photoconductor, it is advantageous for high image quality and downsizing of an apparatus, and proximity charging that can reduce the generation amount of oxidizing gas such as ozone and NOx as compared with a scorotron / corotron charging method. The method is being adopted. Here, the proximity charging method refers to a charging method in which a charging member made of a charging roller or the like is charged by contacting or approaching the surface of the photoreceptor.

  However, the proximity charging method has a problem in that since the discharge energy is large, the degree of wear of the surface layer increases, and sufficient durability cannot be obtained, resulting in hindering the long life.

  In order to solve such a problem, the film thickness of the photoconductor is increased in advance (see, for example, Patent Document 1), or a filler such as metal oxide fine particles is added to the surface layer of the photoconductor. (For example, refer to Patent Document 2).

However, if a photoconductor with a large film thickness is used, the resolution of the formed image is lowered, so that the initial high image quality cannot be satisfactorily achieved. In particular, as the durability progresses, that is, as the usage period becomes longer, the resolution decreases. This is presumably because the shape of the surface of the photoconductor changes as the durability progresses, so that the charge estimated to be located near the surface of the photoconductor is influenced by the surface shape. The tendency of the resolution to decrease is noticeable when the contact charging method is charged among the proximity charging methods, particularly when the contact charging method in which an alternating voltage is applied in a superimposed manner.
In addition, if charging is performed on a photoconductor in which a filler is added to the surface layer, for example, by applying an AC voltage in a superimposed manner, resistance to discharge of the resin constituting the surface layer is not sufficient. Further, there is a problem that the wear of the photoconductor progresses due to the disconnection of the resin bond due to the decrease in strength at the discharge portion.

Japanese Patent No. 4144493 Japanese Patent No. 5391672

  The present invention has been made based on the circumstances as described above, and an object of the invention is to provide an electronic device that can obtain high durability and can form a high-resolution image even when used repeatedly over a long period of time. It is an object of the present invention to provide a photographic photoreceptor and an image forming apparatus including the same.

The electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member in which an intermediate layer, a photosensitive layer and a surface layer are laminated in this order on a conductive support,
From a cured product of a composition in which the surface layer contains a monomer having an alkoxysilane structure, metal oxide fine particles having a reactive organic group that reacts with a group other than the polymerizable reactive group in the monomer, and an electron transport agent. It is characterized by becoming.

In the electrophotographic photoreceptor of the present invention, the metal oxide fine particles are preferably composed of at least one selected from the group consisting of SnO ₂ , SiO _2, and Al ₂ O ₃ .

  In the electrophotographic photoreceptor of the present invention, it is preferable that the electron transport agent is composed of a compound having a naphthoquinone structure represented by the following general formula (1).

[Wherein, R ¹ and R ² each independently represent an alkyl group having 1 to 6 carbon atoms, and n is 0 or 1. ]

  In the electrophotographic photoreceptor of the present invention, the total layer thickness of the photosensitive layer and the surface layer is preferably 20 μm or less.

  In the electrophotographic photosensitive member of the present invention, the surface layer preferably has a layer thickness of 4 μm or less.

The image forming apparatus of the present invention includes an electrophotographic photosensitive member, a proximity charging method charging unit that charges the surface of the electrophotographic photosensitive member, an exposure unit that exposes the electrophotographic photosensitive member charged by the charging unit, An image forming apparatus comprising: a developing unit that supplies toner to the electrophotographic photosensitive member exposed by the exposing unit to form a toner image;
The electrophotographic photosensitive member is the above-described electrophotographic photosensitive member.

  In the image forming apparatus according to the present invention, the proximity charging type charging unit may include a charging member in contact with the surface layer.

  In the image forming apparatus of the present invention, the charging member may apply an alternating voltage in a superimposed manner.

  According to the electrophotographic photoreceptor of the present invention, the surface layer of the composition containing a monomer having an alkoxysilane structure, metal oxide fine particles having a reactive organic group that reacts with the monomer, and an electron transport agent. By comprising a cured product, high durability can be obtained and a high-resolution image can be formed even when used repeatedly over a long period of time.

FIG. 3 is a partial cross-sectional view illustrating an example of a layer configuration of the electrophotographic photoreceptor of the present invention. 1 is a cross-sectional view illustrating the configuration of an example of an image forming apparatus according to the present invention. It is a chart used in evaluation of an Example and a comparative example.

  Hereinafter, the present invention will be specifically described.

[Photoreceptor]
The photoconductor of the present invention is a photoconductor mounted on an image forming apparatus including a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit, and has an intermediate layer, a photosensitive layer, and a surface layer on a conductive support. Are organic photoreceptors laminated in this order.

  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 structure of the photoreceptor is exhibited by an organic compound. Or a photosensitive member having an organic photosensitive layer composed of an organic charge transport material, a photosensitive member having all known organic photoreceptors, such as a photosensitive member having an organic photosensitive layer in which a charge generation function and a charge transport function are composed of a polymer complex. Say.

  For example, as shown in FIG. 1, the photoconductor is formed by laminating an intermediate layer 1b, a charge generation layer 1c, a charge transport layer 1d, and a surface layer 1e in this order on a conductive support 1a. The charge generation layer 1c and the charge transport layer 1d constitute a photosensitive layer 1f.

[Surface layer 1e]
The surface layer 1e constituting the photoreceptor of the present invention comprises a metal oxide fine particle (hereinafter referred to as “specific layer”) having a monomer having an alkoxysilane structure and a reactive organic group that reacts with a group other than the polymerizable reactive group in the monomer. Also referred to as “metal oxide fine particles.”) A cured product of a composition containing 1eA and an electron transport agent (hereinafter also referred to as “surface layer composition”). That is, in the surface layer 1e, specific metal oxide fine particles are derived from reactive organic groups in a binder resin (hereinafter also referred to as “specific siloxane resin”) made of a cured product of a monomer having an alkoxysilane structure. In addition to being bonded via a group, an electron transfer agent is contained.

According to the above photoreceptor, the surface layer 1e is made of a cured product of a composition for a surface layer containing a monomer having an alkoxysilane structure, specific metal oxide fine particles 1eA, and an electron transport agent. In addition, high durability can be obtained and a high-resolution image can be formed even when used repeatedly over a long period of time, that is, at the end of durability.
First, since the surface layer 1e contains a specific siloxane resin, a high film hardness is obtained, and the filler effect is obtained by containing the specific metal oxide fine particles 1eA in the surface layer 1e. As a result, a higher film hardness can be obtained, whereby high durability can be obtained.
According to this photoreceptor, the Si—O bond in a specific siloxane resin is strong because the bond energy is larger than the C—C bond with respect to the discharge energy, and therefore the chemical bond is broken by the discharge energy of charging. In addition, since the specific metal oxide fine particles 1eA are bonded to a specific siloxane resin through a group derived from a reactive organic group, the resistance to discharge energy is higher. Therefore, a high-resolution image can be formed even at the end of durability. Further, the negative charge imparted by the charging means is transported to the boundary region between the surface layer 1e and the charge transport layer 1d by the electron transport agent, and the negative transport is carried out by the holes transported from the conductive support 1a in this region. It is considered that the charge is erased, so that the negative charge can be surely erased even if the physical surface shape of the photoreceptor changes at the end of the durability. Therefore, a high-resolution image can be formed even at the end of durability.
The inventors of the present invention dramatically improved the stability of negative charge transport by such an electron transport agent when the electron transport agent is contained in a resin having a Si—O bond (specific siloxane resin). I found it to be improved. The reason for this is not clear, but the Si—O bond in a specific siloxane resin is not easily linear, so that it is easy to polarize, which is advantageous for the transport of negative charges of the electron transport agent. Can be guessed.

Further, according to the image forming apparatus of the present invention provided with such a photoreceptor, even when the charging means is of a proximity charging type, high durability can be obtained and a high-resolution image can be formed at the end of the durability. be able to.
Note that when using a photoreceptor with a surface layer made of a normal resin, resolution declined at the end of durability, and this tendency was superimposed on the charging of the contact charging method, particularly the AC voltage, among the proximity charging methods. This is noticeable when charging by the contact charging method to be applied.

[Specific siloxane resin]
The specific siloxane resin is a polymerization cured product of the composition for a surface layer containing a monomer having an alkoxysilane structure.
The monomer having an alkoxysilane structure refers to a monomer having a siloxane bond (—OSi—) in a structural unit after polymerization and curing. The monomer having an alkoxysilane structure according to the present invention may be in the form of a polymer before an oligomer or a crosslinked network is formed.

As the monomer having an alkoxysilane structure according to the present invention, an organosilicon compound represented by the following general formula (2) (hereinafter also referred to as “specific organosilicon compound”) is preferably used.
General formula (2): (R) _m- Si- (X) _4-m
[In the formula, R represents an organic group in which carbon is directly bonded to an adjacent silicon atom (Si), X represents a hydrolyzable group, and m represents an integer of 0 to 3. ]
In a specific organosilicon compound, the organic group that is the group R includes an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, and a dodecyl group; a phenyl group, a tolyl group, Aryl groups such as naphthyl group and biphenyl group; epoxy-containing groups such as γ-glycidoxypropyl group and β- (3,4-epoxycyclohexyl) ethyl group; γ-acryloxypropyl group and γ-methacryloxypropyl group (Meth) acryloyl group such as γ-hydroxypropyl group, 2,3-dihydroxypropyloxypropyl group and other hydroxyl groups; vinyl group, propenyl group and other vinyl groups; γ-mercaptopropyl group and other mercapto groups Amino-containing groups such as γ-aminopropyl group and N-β (aminoethyl) -γ-aminopropyl group; A nitro group; Roropuropiru group, 1,1,1-fluoroalkyl propyl, nonafluorohexyl group, a halogen-containing group, such as perfluorooctyl ethyl group and cyano-substituted alkyl group.
Moreover, examples of the hydrolyzable group as the group X include alkoxy groups such as methoxy group and ethoxy group; halogen groups; acyloxy groups.

  In the specific organosilicon compound, when m is 2 or 3, the plurality of groups R may be the same or different. Similarly, when m is 0 or 1, the plurality of groups X may be the same or different. Further, when two or more specific organosilicon compounds are used in combination, the group R and the group X may be the same or different between the respective compounds.

Specific examples of the specific organosilicon compound in which m is 0 include tetrachlorosilane, diethoxydichlorosilane, tetramethoxysilane, phenoxytrichlorosilane, tetraacetoxysilane, tetraethoxysilane, tetraallyloxysilane, tetrapropoxysilane, tetra Examples include isopropoxysilane, tetrakis (2-methoxyethoxy) silane, tetrabutoxysilane, tetraphenoxysilane, tetrakis (2-ethylbutoxy) silane, tetrakis (2-ethylhexyloxy) silane, and the like.
Specific examples of the specific organosilicon compound in which m is 1 include trichlorosilane, methyltrichlorosilane, vinyltrichlorosilane, ethyltrichlorosilane, allyltrichlorosilane, n-propyltrichlorosilane, n-butyltrichlorosilane, chloromethyltrichlorosilane. Ethoxysilane, methyltrimethoxysilane (compound represented by the following formula (1)), mercaptomethyltrimethoxysilane, trimethoxyvinylsilane, ethyltrimethoxysilane, 3,3,4,4,5,5,6,6 , 6-Nonafluorohexyltrichlorosilane, phenyltrichlorosilane, 3,3,3-trifluoropropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, triethoxysilane, methyltriethoxysilane (represented by the following formula (3) Compound 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 2-aminoethylaminomethyltrimethoxysilane, benzyltrichlorosilane, methyltriacetoxysilane, chloromethyltriethoxysilane, ethyltriacetoxysilane, phenyltrimethoxy Silane, 3-allylthiopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-bromopropyltriethoxysilane, 3-allylaminopropyltrimethoxysilane, propyltriethoxysilane, hexyltrimethoxysilane, 3- Aminopropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane (compound represented by the following formula (5)), bis (ethylmethylketoxime) methoxymethylsilane Pen triethoxysilane, octyltriethoxysilane, and the like dodecyl triethoxysilane.
Specific examples of the specific organosilicon compound in which m is 2 include dimethyldichlorosilane, dimethoxymethylsilane, dimethoxydimethylsilane (compound represented by the following formula (2)), methyl-3,3,3-trifluoro Propyldichlorosilane, diethoxysilane, diethoxymethylsilane, dimethoxymethyl-3,3,3-trifluoropropylsilane, 3-chloropropyldimethoxymethylsilane, chloromethyldiethoxysilane, diethoxydimethylsilane (the following formula (4 ), Dimethoxy-3-mercaptopropylmethylsilane, 3,3,4,4,5,5,6,6,6-nonafluorohexylmethyldichlorosilane, methylphenyldichlorosilane, diacetoxymethyl Vinylsilane, diethoxymethylvinylsilane, 3- Tacryloxypropylmethyldichlorosilane, 3-aminopropyldiethoxymethylsilane, 3- (2-aminoethylaminopropyl) dimethoxymethylsilane, t-butylphenyldichlorosilane, 3-methacryloxypropyldimethoxymethylsilane, 3- (3 -Cyanopropylthiopropyl) dimethoxymethylsilane, 3- (2-acetoxyethylthiopropyl) dimethoxymethylsilane, dimethoxymethyl-2-piperidinoethylsilane, dibutoxydimethylsilane, 3-dimethylaminopropyldiethoxymethylsilane, Diethoxymethylphenylsilane, diethoxy-3-glycidoxypropylmethylsilane, 3- (3-acetoxypropylthio) propyldimethoxymethylsilane, dimethoxymethyl-3-piperidinopropi Silane, such as diethoxymethyl octadecyl silane.
Specific examples of the specific organosilicon compound in which m is 3 include trimethylchlorosilane, methoxytrimethylsilane, ethoxytrimethylsilane, methoxydimethyl-3,3,3-trifluoropropylsilane, 3-chloropropylmethoxydimethylsilane, methoxy -3-mercaptopropylmethylmethylsilane and the like.
Of these, trimethoxymethylsilane, dimethoxydimethylsilane, triethoxymethylsilane, and diethoxydimethylsilane are preferably used.

  The above-mentioned monomers listed as monomers having an alkoxysilane structure can be used alone or in combination of two or more.

The specific siloxane resin constituting the surface layer 1e may contain a structural unit derived from another monomer other than the monomer having the alkoxysilane structure.
Other monomers other than the monomer having an alkoxysilane structure include, for example, a methacrylate having a hydroxyl group, an epoxy group or a glycidyl group, an acrylate having a hydroxyl group, an epoxy group or a glycidyl group, a vinyl compound having a hydroxyl group, an epoxy group or a glycidyl group. Can be mentioned.

[Specific metal oxide fine particles 1eA]
The specific metal oxide fine particle 1eA according to the present invention has a reactive organic group that reacts with a group other than the polymerizable reactive group in the monomer having an alkoxysilane structure on the surface thereof. Specifically, A reactive organic group (hereinafter, referred to as “raw metal oxide fine particle”) as a raw material reacts with a group other than the polymerizable reactive group in the monomer having an alkoxysilane structure. Surface treatment with a surface treatment agent (hereinafter, also referred to as “specific reactive organic group-containing surface treatment agent”) having a “specific reactive organic group”) causes the specific reactive organic group. Is bonded to the surface of the raw material metal oxide fine particles.

[Raw metal oxide fine particles]
The raw material metal oxide fine particles have at least a part of the surface formed of a metal oxide, and may be formed of a single material or a plurality of materials.
Specific examples of the raw material metal oxide fine particles composed of a plurality of materials include core-shell structure composite fine particles in which a metal oxide is attached to the surface of a core material as a coating material. The composite fine particles having the core-shell structure may be one in which a part of the surface of the core material is exposed, or the core material surface may be completely covered with a coating material.

Examples of the raw material metal oxide fine particles composed of a single material include silicon oxide (SiO ₂ ), magnesium oxide, zinc oxide, lead oxide, aluminum oxide (Al ₂ O ₃ ), zirconium oxide, and tin oxide (SnO _2). ), Fine particles of titanium oxide, niobium oxide, molybdenum oxide, vanadium oxide, and the like. Among these, it is preferable to use tin oxide (SnO ₂ ), silicon oxide (SiO ₂ ), and aluminum oxide (Al ₂ O ₃ ) from the viewpoints of hardness, insulation, and light transmittance.

An insulating material is used as the core material of the composite fine particles having the core-shell structure, and specific examples include barium sulfate, silicon oxide, and aluminum oxide. As the core material, it is particularly preferable to use barium sulfate from the viewpoint of light transmittance. Examples of the metal oxide as the coating material include silicon oxide, aluminum oxide, and calcium oxide.
By using oxide fine particles composed of such core-shell composite fine particles, it is possible to ensure insulation while ensuring light transmission, and thus wear resistance while ensuring the desired image characteristics. Enough.
In the composite fine particles having the core-shell structure, the adhesion amount of the metal oxide to the core material is preferably 30 to 80% by mass, and more preferably 40 to 70% by mass with respect to the core material. As a method for attaching the metal oxide, which is a coating material, to the core material, for example, a method disclosed in Japanese Patent Application Laid-Open No. 2009-255042 can be employed.

  These raw material metal oxide fine particles can be used alone or in combination of two or more.

[Surface treatment of raw metal oxide fine particles]
The specific reactive organic group-containing surface treatment agent used for the surface treatment of the raw material metal oxide fine particles can be a compound having a specific reactive organic group.
By using a specific reactive organic group-containing surface treating agent, the specific metal oxide fine particle 1eA has a specific reactive organic group. Such a specific metal oxide fine particle 1eA is converted into an alkoxysilane structure. Chemistry with the monomer having the alkoxysilane structure by forming a specific siloxane resin, which is a polymerized cured product of the composition for the surface layer containing the monomer, with a monomer having the alkoxysilane structure. As a result, the surface layer 1e having high durability can be formed.

  Specific reactive organic groups include hydroxyl groups, epoxy groups, glycidyl groups, oxetanyl groups and the like.

  Examples of the specific reactive organic group-containing surface treatment agent include known compounds represented by the following formulas (S-1) to (S-5).

  These specific reactive organic group-containing surface treatment agents can be used alone or in combination of two or more.

  The amount of the specific reactive organic group-containing surface treatment agent is not particularly limited, but is preferably 0.1 to 10 parts by weight, particularly preferably 3 to 100 parts by weight of the raw metal oxide fine particles. -7 parts by mass. When the amount of the specific reactive organic group-containing surface treatment agent used is excessive, the residue of the specific reactive organic group-containing surface treatment agent may remain on the raw material metal oxide fine particles, There is a possibility that a specific reactive organic group-containing surface treatment agent may be further bonded to the specific reactive organic group-containing surface treatment agent bonded to the fine particles.

The number average primary particle size of the specific metal oxide fine particles 1eA is preferably 3 to 150 nm, more preferably 10 to 50 nm.
When the number average primary particle size of the specific metal oxide fine particles 1eA is within the above range, a sufficiently high film strength can be ensured. On the other hand, when the number average primary particle size of the specific metal oxide fine particles 1eA is less than 3 nm, the dispersibility in the coating liquid for forming the surface layer 1e is low, and thus the specific metal oxide fine particles 1eA Aggregates, and therefore a uniform coating may not be formed. In addition, when the number average primary particle size of the specific metal oxide fine particles 1eA exceeds 150 nm, the uniformity of dispersion in the surface layer 1e is low, and the surface roughness tends to increase when used over a long period of time. There is.

  The number average primary particle size of the specific metal oxide fine particles 1eA is measured as follows. First, as a measurement sample, the photosensitive layer 1f including the surface layer 1e is cut out from the surface of the photoreceptor with a knife or the like, and attached to an arbitrary holder so that the cut surface faces upward. Then, the measurement sample was taken with a scanning electron microscope, an enlarged photograph with a magnification of 30,000 times, and the photograph image (excluding aggregated particles) captured by the scanner was used as an automatic image processing analyzer “LUZEX (registered trademark)” ) AP (software version Ver. 1.32) ”(manufactured by Nireco) was used to binarize the specific metal oxide fine particles 1eA, and horizontal for any 100 specific metal oxide fine particles 1eA The direction ferret diameter is calculated, and the average value is defined as the number average primary particle diameter. Here, the horizontal ferret diameter refers to the length of a side parallel to the x-axis of the circumscribed rectangle when the image of the specific metal oxide fine particle 1eA is binarized.

The specific metal oxide fine particles 1eA are preferably contained at a ratio of 15 to 120 parts by mass with respect to 100 parts by mass of the specific siloxane resin.
When the content ratio of the specific metal oxide fine particles 1eA is within the above range, the hardness of the surface layer 1e can be appropriately adjusted.

[Electron transport agent]
As the electron transporting agent, various conventionally known electron transporting agents can be used, and it is particularly preferable to use a compound having a naphthoquinone structure represented by the general formula (1).
As the electron transfer agent, it is more preferable to use a compound having an electron mobility of 1.0 × 10 ⁻⁸ cm ² / V / sec or more at an electric field strength of 5 × 10 ⁵ v / cm.

In the general formula (1), R ¹ and R ² are each independently an alkyl group having 1 to 6 carbon atoms, and n is 0 or 1.

  Examples of the electron transporting agent other than the compound having a naphthoquinone structure represented by the general formula (1) include benzoquinone derivatives, anthraquinone derivatives, malononitrile derivatives, thiopyran derivatives, trinitrothioxanthone derivatives, 3,4,5,7- Tetranitro-9-fluorenone derivative, dinitroanthracene derivative, dinitroacridine derivative, nitroantaraquinone derivative, dinitroanthraquinone derivative, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone , Dinitroanthraquinone, succinic anhydride, maleic anhydride, dibromomaleic anhydride and the like.

  Specific examples of the electron transfer agent include compounds represented by the following formulas (A1) to (A6).

  Said electron transfer agent can be used individually or in mixture of 2 or more types.

The electron transfer agent is preferably contained in a proportion of 10 to 60 parts by mass, more preferably 20 to 50 parts by mass with respect to 100 parts by mass of the specific siloxane resin.
When the content ratio of the electron transport agent is within the above range, an appropriate electron transport property can be obtained in the surface layer 1e.

  In addition to the specific siloxane resin as described above, the specific metal oxide fine particles and the electron transport agent, the surface layer 1e contains lubricant particles, organic fine particles, various antioxidants, and the like as necessary. May be.

[Lubricant particles]
Examples of the lubricant particles include fluorine atom-containing resin particles. Examples of the fluorine atom-containing resin particles include ethylene tetrafluoride resin, ethylene trifluoride chloride resin, hexafluoroethylene chloride propylene resin, vinyl fluoride resin, vinylidene fluoride resin, and ethylene difluoride dichloride resin. These copolymers can also be used. These can be used individually by 1 type or in combination of 2 or more types. Among these, it is particularly preferable to use a tetrafluoroethylene resin and a vinylidene fluoride resin.

[Organic fine particles]
When the surface layer 1e is made of a specific siloxane resin as in the photoconductor of the present invention, the torque by the cleaning blade tends to increase, but the surface of the photoconductor is moderately roughened by adding organic fine particles. And the surface energy of the organic fine particles can reduce the torque generated by the cleaning blade and improve the cleaning performance.
As the organic fine particles, for example, crosslinked styrene acrylic resin, benzoguanamine-melamine-formaldehyde condensate, benzoguanamine resin fine particles, and melamine resin fine particles can be used.

The layer thickness of the surface layer 1e can be, for example, 4 μm or less, and specifically 0.1 to 3 μm is preferable.
When the layer thickness of the surface layer 1e is within the above range, the negative charge imparted by the charging means can be reliably transported from the surface of the surface layer 1e to the boundary region with the charge transport layer 1d.

The universal hardness of the surface layer 1e is preferably 200 N / mm ² or more and 320 N / mm ² or less.
When the universal hardness of the surface layer 1e is in the above range, appropriate wear resistance can be obtained for the photoreceptor.

In the present invention, the universal hardness of the surface layer 1e is a value measured by an ultra micro hardness test system “Fischer Scope H100” (Fischer Instruments).
Specifically, from the indentation depth h and the load F when the surface of the photoreceptor is pushed by applying a load F to the diamond square pyramid Vickers indenter under the test load with the “Fischer scope H100”, the following formula (HU) is used. Ask.
Formula (HU): HU (Universal hardness) = F / (26.45 × h ² )

  The universal hardness of the surface layer 1e depends on the curing conditions (ultraviolet irradiation time and ultraviolet species) when forming the surface layer 1e, the monomer having an alkoxysilane structure, and other types of monomers used as necessary. Can be controlled.

(Formation of surface layer)
The surface layer 1e is a composition for a surface layer containing a monomer having an alkoxysilane structure, specific metal oxide fine particles 1eA, and an electron transport agent, and a known resin, photobase generator, lubricant particle, oxidation A coating solution prepared by adding an inhibitor, a solvent, and the like can be prepared by coating the surface of the charge transport layer 1d by a known method to form a coating film, followed by curing.
Examples of the reaction between monomers having an alkoxysilane structure and the reaction between a monomer having an alkoxysilane structure and a specific reactive organic group of the specific metal oxide fine particle 1eA include, for example, a hydrolysis / polycondensation reaction by a sol-gel method. Alternatively, a reaction with a photobase generator can be used.

Various known compounds can be used as the photobase generator.
The usage-amount of a photobase generator is 0.1-40 mass parts with respect to 100 mass parts of monomers which have an alkoxysilane structure, for example, Preferably it is 0.5-20 mass parts.

〔solvent〕
Solvents used for forming the surface layer 1e include pure water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-2-propanol, benzyl alcohol, and methyl isopropyl ketone. , Methyl isobutyl ketone, methyl ethyl ketone, cyclohexane, toluene, xylene, methylene chloride, ethyl acetate, butyl acetate, 2-methoxyethanol, 2-ethoxyethanol, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine and diethylamine However, it is not limited to these.
These can be used individually by 1 type or in mixture of 2 or more types.

  In the curing process, for example, when a reaction using a photobase generator is performed, the coating film is irradiated with ultraviolet rays to generate a base and polymerize, and a cross-linking bond is formed by a cross-linking reaction between molecules and within the molecule. And can be cured to produce a specific siloxane resin.

  As the ultraviolet light source, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a flash (pulse) xenon, an ultraviolet LED, or the like can be used.

  The irradiation time of the ultraviolet rays may be any time as long as the necessary irradiation amount of the ultraviolet rays can be obtained. Specifically, the irradiation time is preferably 0.1 seconds to 10 minutes, and more preferably 1 second to 5 minutes from the viewpoint of curing efficiency or work efficiency. .

  The coating film may be dried before and after UV irradiation and during UV irradiation. The timing for performing the drying treatment can be appropriately selected in combination with the irradiation condition of ultraviolet rays. The drying conditions for the surface layer 1e can be appropriately selected depending on the type of solvent used in the coating solution, the film thickness of the surface layer 1e, and the like. The drying temperature is preferably room temperature to 180 ° C, particularly preferably 80 to 140 ° C. The drying time is preferably 1 to 200 minutes, particularly preferably 5 to 100 minutes. By drying the coating film under such drying conditions, the amount of the solvent contained in the surface layer 1e can be controlled in the range of 20 ppm to 75 ppm.

  Hereinafter, the structure of the photoreceptor other than the surface layer 1e will be described.

[Conductive support 1a]
The conductive support 1a may be anything as long as it has conductivity, for example, a metal such as aluminum, copper, chromium, nickel, zinc, and stainless steel formed into a drum or a sheet, or a metal foil such as aluminum or copper. Laminated on plastic film, aluminum, indium oxide, tin oxide, etc. deposited on plastic film, metal with conductive layer applied alone or with binder resin, plastic film and paper It is done.

[Intermediate layer 1b]
The intermediate layer 1b provides a barrier function and an adhesive function between the conductive support 1a and the photosensitive layer 1f. It is preferable to provide such an intermediate layer 1b from the viewpoint of preventing various failures.

  Such an intermediate layer 1b contains, for example, a binder resin (hereinafter also referred to as “binder resin for intermediate layer”) and, if necessary, conductive particles and metal oxide particles.

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

The intermediate layer 1b can contain various conductive particles and metal oxide particles for the purpose of resistance adjustment. For example, various metal oxide particles such as alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, and bismuth oxide can be used. Ultrafine particles such as indium oxide doped with tin, tin oxide doped with antimony, and zirconium oxide can be used.
The number average primary particle size of such metal oxide particles is preferably 0.3 μm or less, and more preferably 0.1 μm or less.
You may use a metal oxide particle individually by 1 type or in mixture of 2 or more types. When two or more kinds are mixed, it may take the form of a solid solution or fusion.

  It is preferable that the content rate of electroconductive particle or metal oxide particle is 20-400 mass parts with respect to 100 mass parts of binder resin for intermediate | middle layers, More preferably, it is 50-200 mass parts.

The intermediate layer 1b as described above is prepared, for example, by dissolving a binder resin for an intermediate layer in a known solvent, and dispersing conductive particles or metal oxide particles as necessary to prepare a coating solution for forming an intermediate layer. The intermediate layer forming coating solution can be formed by coating the surface of the conductive support 1a to form a coating film and drying the coating film.
The density | concentration of the binder resin for intermediate | middle layers in the coating liquid for intermediate | middle layer formation can be suitably selected according to the layer thickness of the intermediate | middle layer 1b, and the coating method.

  The solvent used for forming the intermediate layer 1b is not particularly limited, and various known organic solvents can be used. However, good solubility and coating with respect to a polyamide resin that is preferable as a binder resin for the intermediate layer. In order to express performance, it is preferable to use alcohols having 2 to 4 carbon atoms such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol and the like. Moreover, in order to improve preservability and the dispersibility of electroconductive particle or metal oxide particle, a cosolvent can be used together with the said solvent. Preferred examples of the cosolvent include methanol, benzyl alcohol, toluene, cyclohexanone, tetrahydrofuran and the like. These solvents and cosolvents can be used alone or in combination of two or more.

  As a means for dispersing the conductive particles and metal oxide particles, an ultrasonic disperser, a ball mill, a sand grinder, a homomixer, or the like can be used.

  The coating method for the intermediate layer forming coating solution is not particularly limited. For example, dip coating method, spray coating method, spinner coating method, bead coating method, blade coating method, beam coating method, circular amount regulation type coating method ( A circular slide hopper coating method).

  As a method for drying the coating film, a known drying method can be appropriately selected according to the type of the solvent and the film thickness of the intermediate layer 1b to be formed, and it is particularly preferable to perform heat drying.

  The layer thickness of the intermediate layer 1b is preferably 0.1 to 15 μm, and more preferably 0.3 to 10 μm.

[Charge generation layer 1c]
The charge generation layer 1c contains a charge generation material and a binder resin (hereinafter also referred to as “binder resin for charge generation layer”).

  Examples of charge generation materials include azo raw materials such as Sudan Red and Diane Blue, quinone pigments such as pyrenequinone and anthanthrone, quinocyanine pigments, perylene pigments, indigo pigments such as indigo and thioindigo, pyranthrone and diphthaloylpyrene. Examples thereof include, but are not limited to, ring quinone pigments and phthalocyanine pigments. Among these, polycyclic quinone pigments and titanyl phthalocyanine pigments are preferable. These charge generation materials may 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 resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, and copolymer resin containing two or more of these resins (for example, vinyl chloride-vinyl acetate copolymer resin, chloride) Vinyl-vinyl acetate-maleic anhydride copolymer resin), poly-vinylcarbazole resin, and the like, but are not limited thereto. Among these, polyvinyl butyral resin is preferable.

  The mixing ratio of the charge generation layer binder resin and the charge generation material is preferably 1 to 600 parts by mass, more preferably 50 to 500 parts by mass, relative to 100 parts by mass of the charge generation layer binder resin. Part by mass. When the mixing ratio of the charge generating layer binder resin and the charge generating material is in the above range, high dispersion stability is obtained in the coating solution for forming the charge generating layer, which will be described later. The resistance is suppressed to be low, and an increase in residual potential due to repeated use can be extremely suppressed.

  The charge generation layer 1c as described above is prepared by, for example, adding a charge generation material into a charge generation layer binder resin dissolved in a known solvent and dispersing it to prepare a charge generation layer forming coating solution. It can be formed by applying a coating solution for generating a layer on the surface of the intermediate layer 1b to form a coating film and drying the coating film.

  As the solvent used for forming the charge generation layer 1c, a solvent capable of dissolving the charge generation layer binder resin may be used. For example, ketone solvents such as methyl ethyl ketone and cyclohexanone, tetrahydrofuran, 1-dioxane, 1, Ether solvents such as 3-dioxolane, alcohol solvents such as methyl cellsolve, ethyl cellsolve, methanol, ethanol, propanol and butanol, ester solvents such as ethyl acetate and t-butyl acetate, aromatics such as toluene and xylene Although a solvent etc. can be mentioned, it is not limited to these. These may be used alone or in combination of two or more.

Examples of the means for dispersing the charge generating substance include the same method as the means for dispersing the conductive particles and metal oxide particles in the coating liquid for forming the intermediate layer.
Examples of the coating method for the charge generation layer forming coating solution include the same methods as those mentioned as the coating method for the intermediate layer forming coating solution.

  The layer thickness of the charge generation layer 1c varies depending on the characteristics of the charge generation material, the characteristics and the content ratio of the binder resin for the charge generation layer, but is preferably 0.01 to 5 μm, more preferably 0.05 to 3 μm. .

[Charge transport layer 1d]
The charge transport layer 1d contains a charge transport material and a binder resin (hereinafter also referred to as “binder resin for charge transport layer”).

  As the charge transport material of the charge transport layer 1d, for example, carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, Bisimidazolidine derivatives, styryl compounds, hydrazone compounds, pyrazoline compounds, oxazolone derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, phenylenediamine derivatives, stilbene derivatives, benzidine Derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene and the like. That. These may be used alone or in combination of two or more.

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

  The content ratio of the charge transport material in the charge transport layer 1d is preferably 10 to 500 parts by weight, more preferably 20 to 100 parts by weight with respect to 100 parts by weight of the charge transport layer binder resin.

  In the charge transport layer 1d, an antioxidant, an electronic conductive agent, a stabilizer, silicone oil, or the like may be added. As the antioxidant, those disclosed in JP-A No. 2000-305291 and as the electronic conductive agent are disclosed in JP-A Nos. 50-137543 and 58-76483.

  The layer thickness of the charge transport layer 1d varies depending on the characteristics of the charge transport material, the characteristics and the content ratio of the binder resin for the charge transport layer, and is preferably 5 to 40 μm, more preferably 10 to 30 μm.

For the charge transport layer 1d as described above, for example, a charge transport material (CTM) is added and dispersed in a charge transport layer binder resin dissolved in a known solvent to prepare a charge transport layer forming coating solution. The coating liquid for forming the charge transport layer can be applied to the surface of the charge generation layer 1c to form a coating film, and the coating film can be dried.
Examples of the solvent used in the formation of the charge transport layer 1d include the same solvents as those used in the formation of the charge generation layer 1c.
In addition, as the method for applying the charge transport layer forming coating solution, the same method as the method for applying the charge generating layer forming coating solution can be used.

In the present invention, the total thickness of the photosensitive layer 1f and the surface layer 1e, that is, the total thickness of the charge generation layer 1c, the charge transport layer 1d and the surface layer 1e is preferably 20 μm or less, more preferably 15 to 18 μm.
In the case of performing image formation by proximity charging, the thinner the photosensitive member is, the easier it is to charge, and the deterioration of the electrostatic latent image due to diffusion is suppressed, so the total of the photosensitive layer 1f and the surface layer 1e is reduced. When the layer thickness is 20 μm or less, a high-resolution image can be reliably formed.
When the layer thickness of the photosensitive layer 1f is excessive, charging failure is likely to occur when contact charging is performed, and halftone streaks due to charging failure particularly in a low temperature and low humidity environment are likely to occur.

The total thickness of the photosensitive layer 1f and the surface layer 1e is “FISCHERSCOPE MMS film thickness meter” (Fischer Instruments Co., Ltd.) under the environment of a temperature of 23 ° C. and a humidity of 50% for the film in which the photosensitive layer 1f and the surface layer 1e are laminated. This is a value measured by
The film in which the photosensitive layer 1f and the surface layer 1e are laminated is formed by applying the photosensitive layer 1f and the surface layer 1e only on the conductive support 1a by the above-described method.

[Image forming apparatus]
An image forming apparatus of the present invention includes the above-described photoreceptor.
Specifically, for example, the above-described photoconductor, a proximity charging type charging unit that negatively charges the surface of the photoconductor, and exposure that forms an electrostatic latent image by exposing the photoconductor charged by the charging unit. Developing means for supplying toner to the photoreceptor and developing the electrostatic latent image with the toner to form a toner image; transfer means for transferring the toner image formed on the photoreceptor; and surface of the photoreceptor And a cleaning means for removing the remaining toner.

FIG. 2 is a cross-sectional view illustrating the configuration of an example of the image forming apparatus of the present invention.
This image forming apparatus is called a tandem type color image forming apparatus, and includes four sets of image forming units (image forming units) 10Y, 10M, 10C, and 10Bk, an intermediate transfer body unit 70, a paper feeding unit 21, and And fixing means 24. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

The four sets of image forming units 10Y, 10M, 10C, and 10Bk are centered around the photoreceptors 1Y, 1M, 1C, and 1Bk, charging means 2Y, 2M, 2C, and 2Bk, and exposure means 3Y, 3M, 3C, and 3Bk, Rotating developing means 4Y, 4M, 4C, 4Bk, primary transfer rollers 5Y, 5M, 5C, 5Bk as primary transfer means, and cleaning means 6Y, 6M, 6C, cleaning the photoreceptors 1Y, 1M, 1C, 1Bk It is composed of 6Bk.
The image forming apparatus according to the present invention uses the above-described photoreceptors of the present invention as the photoreceptors 1Y, 1M, 1C, and 1Bk.

  The image forming units 10Y, 10M, 10C, and 10Bk have the same configuration except that the colors of the toner images formed on the photoreceptors 1Y, 1M, 1C, and 1Bk are different from yellow, magenta, cyan, and black, respectively. The forming unit 10Y will be described in detail as an example.

  The image forming unit 10Y includes a charging unit 2Y, an exposing unit 3Y, a developing unit 4Y, and a cleaning unit 6Y around a photoconductor 1Y as an image forming body, and a yellow (Y) toner image is formed on the photoconductor 1Y. To form.

The charging unit 2Y is a unit that uniformly charges the surface of the photoreceptor 1Y to a negative polarity, and is a proximity charging type.
Here, the proximity charging method refers to a charging method using proximity discharge generated in a minute gap near the surface of the photoreceptor. Specifically, the proximity charging method includes a contact roller charging method, a non-contact roller charging method, a brush charging method, and the like.
As the charging means 2Y, those having a charging member in contact with the surface layer 1e, specifically, those of a contact roller charging method or a brush charging method are preferably used.
As the charging means 2Y, it is particularly preferable to use one having a structure in which an alternating voltage is applied in a superimposed manner by a charging member in contact with the surface layer 1e.
The charging unit 2Y in this example includes a charging roller disposed in contact with the surface of the photoreceptor 1Y and a power source that applies a voltage to the charging roller.
The charging roller is formed by, for example, forming a resistance adjustment layer on a conductive support.

  The exposure unit 3Y is a unit that performs exposure based on an image signal (yellow) on the photoreceptor 1Y to which a uniform potential is applied by the charging unit 2Y, and forms an electrostatic latent image corresponding to a yellow image. As the exposure means 3Y, a device composed of an LED having light emitting elements arranged in an array in the axial direction of the photoreceptor 1Y and an imaging element, a laser optical system, or the like is used.

  The developing means 4Y includes, for example, a developing sleeve that contains a magnet and rotates while holding the developer, and a voltage applying device that applies a DC and / or AC bias voltage between the photosensitive member and the developing sleeve.

  The cleaning unit 6Y is a unit that removes toner remaining on the surface of the photoreceptor 1Y. The cleaning means 6Y in this example includes a cleaning blade and a brush roller provided on the upstream side of the cleaning blade.

  In the image forming apparatus of FIG. 2, the photosensitive member 1Y, the charging unit 2Y, the developing unit 4Y, and the cleaning unit 6Y of the image forming unit 10Y are integrally supported and provided as a process cartridge. It may be configured to be detachable from the main body A of the image forming apparatus via a guide means such as a rail.

  The image forming units 10Y, 10M, 10C, and 10Bk are arranged in tandem in the vertical direction, and an intermediate transfer body unit 70 is arranged on the left side of the photoreceptors 1Y, 1M, 1C, and 1Bk in the drawing. The intermediate transfer body unit 70 is wound around a plurality of rollers 71, 72, 73, and 74, and is supported by a semiconductive endless belt-like intermediate transfer body 77, and a secondary transfer means. It consists of a next transfer roller 5b and a cleaning means 6b.

  The image forming units 10Y, 10M, 10C, and 10Bk and the intermediate transfer body unit 70 are housed in a housing 80. The housing 80 is pulled out from the main body A of the image forming apparatus via support rails 82L and 82R. It is configured to be possible.

  The fixing unit 24 is, for example, a heat roller fixing configured by a heating roller having a heating source therein and a pressure roller provided in pressure contact with the heating roller so as to form a fixing nip portion. One of the methods is mentioned.

  In FIG. 2, the image forming apparatus according to the present invention is shown as a color laser printer, but may be configured as a monochrome laser printer or a copy. In the image forming apparatus according to the present invention, a light source other than a laser, for example, an LED light source can be used as the exposure light source.

In the image forming apparatus as described above, image formation is performed as follows. That is, first, the charging means 2Y, 2M, 2C, and 2Bk are discharged to the surface of the photoreceptors 1Y, 1M, 1C, and 1Bk to be negatively charged (charging process). Next, the exposure means 3Y, 3M, 3C, and 3Bk expose the surfaces of the photoreceptors 1Y, 1M, 1C, and 1Bk based on the image signal to form an electrostatic latent image (exposure process). Next, with the developing means 4Y, 4M, 4C, and 4Bk, toner is applied to the surface of the photoreceptors 1Y, 1M, 1C, and 1Bk and developed to form a toner image (developing process).
Next, the primary transfer rollers 5Y, 5M, 5C, and 5Bk are brought into contact with the rotating intermediate transfer body 77. Thus, the color toner images formed on the photoreceptors 1Y, 1M, 1C, and 1Bk are sequentially transferred onto the rotating intermediate transfer body 77 to form a color toner image (primary transfer process). During the image forming process, the primary transfer roller 5Bk is always in contact with the photoreceptor 1Bk. On the other hand, the other primary transfer rollers 5Y, 5M, and 5C abut against the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  Then, after separating the primary transfer rollers 5Y, 5M, 5C, and 5Bk from the intermediate transfer body 77, the toner remaining on the surfaces of the photoreceptors 1Y, 1M, 1C, and 1Bk is cleaned with cleaning means 6Y, 6M, 6C, and 6Bk. To remove (cleaning step). Thereafter, in preparation for the next image forming process, the surfaces of the photoreceptors 1Y, 1M, 1C, and 1Bk are neutralized by a neutralizing unit (not shown) as necessary. At this time, the negative charges remaining on the surfaces of the photoreceptors 1Y, 1M, 1C, and 1Bk are moved to the charge transport layer 1d side by the electron transport agent, and the negative charges on the surfaces of the photoreceptors 1Y, 1M, 1C, and 1Bk are transferred to holes. Is neutralized and erased.

On the other hand, a transfer material P (for example, a support for carrying a final image such as plain paper or a transparent sheet) accommodated in the paper feed cassette 20 is fed by the paper feed means 21 and a plurality of intermediate rollers 22A, 22B, 22C. , 22D, and the registration roller 23, and is conveyed to a secondary transfer roller 5b as a secondary transfer unit. The secondary transfer roller 5b is brought into contact with the intermediate transfer member 77, whereby a color toner image is formed on the transfer material P. Are transferred at once. The transfer material P onto which the color toner image has been transferred is fixed by the fixing means 24, is sandwiched between the paper discharge rollers 25, and is placed on a paper discharge tray 26 outside the apparatus. The secondary transfer roller 5b is brought into contact with the intermediate transfer member 77 only when secondary transfer is performed.
After the color toner image is transferred to the transfer material P by the secondary transfer roller 5b, the residual toner is removed by the cleaning means 6b from the intermediate transfer body 77 from which the transfer material P is separated by curvature.

[Toner and developer]
The toner used in the image forming apparatus according to the present invention is not particularly limited, but includes toner particles containing a binder resin and a colorant. The toner particles may include other components such as a release agent as desired. It may be contained.

  As the toner, either a pulverized toner or a polymerized toner can be used. However, in the image forming apparatus according to the present invention, it is preferable to use a polymerized toner from the viewpoint of obtaining a high quality image.

  The average particle diameter of the toner is preferably 2 to 8 μm in terms of volume-based median diameter. By setting this range, the resolution can be increased.

  In addition, an appropriate amount of inorganic fine particles such as silica and titania having an average particle diameter of about 10 to 300 nm and an abrasive of about 0.2 to 3 μm can be externally added to the toner particles as external additives.

The toner can be used as a magnetic or nonmagnetic one-component developer, but may be mixed with a carrier and used as a two-component developer.
In the case where the toner is used as a two-component developer, the carrier may be a conventionally known material such as a ferromagnetic metal such as iron, an alloy such as ferromagnetic metal and aluminum and lead, and a compound of ferromagnetic metal such as ferrite and magnetite. In particular, ferrite is preferable.

  As mentioned above, although embodiment of this invention was described concretely, embodiment of this invention is not limited to said example, A various change can be added.

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

[Production Example 1 of Metal Oxide Fine Particles]
2.5 g of the surface treatment agent comprising the compound represented by the above formula (S-1) was dissolved in 10 mL of tetrahydrofuran and stirred, and this was mixed with SiO ₂ “Aerosil 200” (average primary particle size: 12 nm, Nippon Aerosil). After 20.0 g of a glass Pasteur pipette was added dropwise over 2 minutes, the obtained powder was transferred to a 1 L separable flask and heated and stirred under a nitrogen stream for 2 hours. At this time, the nitrogen flow rate was 200 ml / min. The obtained fine particles were designated as metal oxide fine particles [1].

[Production Examples 2 to 5 of metal oxide fine particles]
Metal oxide fine particles were prepared in the same manner as in Preparation Example 1 of metal oxide fine particles, except that the raw material metal oxide fine particles shown in Table 1 were used and the amount of the surface treatment agent was changed as shown in Table 1. [2] to [5] were prepared.
However, Al ₂ O ₃ “Nanotek” and SnO ₂ “Nanotek” are manufactured by CI Kasei Co., Ltd., SiO ₂ “SFP-20M” is manufactured by Denki Kagaku Kogyo Co., Ltd., and SiO ₂ “Aerosil OX50” is manufactured by Nippon Aerosil Co., Ltd. .

Example 1: Photoconductor Preparation Example 1
(1) Production of conductive support The surface of a drum-shaped aluminum support (outer diameter 30 mm) was cut to produce a conductive support [1].

(2) Formation of Intermediate Layer A dispersion was obtained by dispersing the following composition in a batch mode for 5 hours using a sand mill as a disperser.
・ Binder resin for intermediate layer: polyamide resin “CM8000” (manufactured by Toray Industries, Inc.) 1 part by mass ・ Metal oxide particles: titanium oxide “SMT500SAS” (manufactured by Teika) 3 parts by mass ・ Solvent: 10 parts by mass of methanol The mixture was diluted twice with the same mixed solvent, and allowed to stand overnight, followed by filtration (filter; using a lysh mesh 5 μm filter manufactured by Nippon Pole Co., Ltd.) to prepare a coating solution for forming an intermediate layer.
This intermediate layer forming coating solution was applied to the outer peripheral surface of the washed conductive support [1] by a dip coating method and dried to form an intermediate layer [1] having a dry film thickness of 2 μm.

(3) Formation of charge generation layer (3-1) Synthesis of charge generation material 29.2 parts by mass of 1,3-diiminoisoindoline is dispersed in 200 parts by mass of o-dichlorobenzene, and titanium tetra-n-butoxide 20 .4 parts by mass was added and heated at 150 to 160 ° C. for 5 hours under a nitrogen atmosphere. After allowing to cool, the precipitated crystals were filtered, washed with chloroform, washed with 2% aqueous hydrochloric acid, washed with water, washed with methanol, and dried to obtain 26.2 parts by mass (yield 91%) of crude titanyl phthalocyanine.
Next, the crude titanyl phthalocyanine was dissolved by stirring for 1 hour in 250 parts by mass of concentrated sulfuric acid at 5 ° C. or less, and this was poured into 5000 parts by mass of water at 20 ° C. The precipitated crystals were filtered and sufficiently washed with water to obtain 225 parts by mass of a wet paste product.
This wet paste product was frozen in a freezer, thawed again, filtered and dried to obtain 24.8 parts by mass of amorphous titanyl phthalocyanine (yield 86%).
The obtained amorphous titanyl phthalocyanine 10.0 parts by mass and (2R, 3R) -2,3-butanediol 0.94 parts by mass (0.6 equivalent ratio) (equivalent ratio is equivalent ratio to titanyl phthalocyanine) After mixing in 200 parts by mass of orthochlorobenzene (ODB) and heating and stirring at 60 to 70 ° C. for 6 hours, the resulting solution was allowed to stand overnight, methanol was added to the reaction solution, and the resulting crystals were filtered. The filtered crystal was washed with methanol to obtain 10.3 parts by mass of a charge generation material [CG-1] composed of a pigment containing (2R, 3R) -2,3-butanediol adduct titanyl phthalocyanine. .
As a result of measuring the X-ray diffraction spectrum of the charge generation material [CG-1], peaks were observed at 8.3 °, 24.7 °, 25.1 °, and 26.5 °. As a result of measuring an IR spectrum, 970 cm Ti = O of around ^-1, both the absorption of O-Ti-O appears in the vicinity of 630 cm ^-1, also result of thermal analysis of the (TG), 390~410 ℃ The charge generation material [CG-1] thus obtained has a 1: 1 adduct of titanyl phthalocyanine and (2R, 3R) -2,3-butanediol, and titanyl phthalocyanine. Presumed to be a mixture with (non-adduct).
It was 31.2 m < ² > / g when the BET specific surface area of the obtained electric charge generation material [CG-1] was measured with the flow type specific surface area automatic measuring device (Micrometrics flow soap type: Shimadzu Corp. make). .
(3-2) Formation of Charge Generation Layer The following raw materials were mixed and dispersed for 10 hours using a sand mill to prepare a charge transport layer forming coating solution [1].
Charge generation material [CG-1] 20 parts by mass Binder resin for charge generation layer: polyvinyl butyral resin “# 6000-C” (manufactured by Denki Kagaku Kogyo) 12 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], this coating solution [1] for forming a charge generation layer is applied by a dip coating method to form a coating film, This coating film was dried to form a charge generation layer [1] having a layer thickness of 0.3 μm.

(4) Formation of charge transport layer The following raw materials were mixed and dissolved to prepare a charge transport layer forming coating solution [1].
Charge transport material: 225 parts by mass of a compound represented by the following formula (CTM) Binder resin for charge transport layer: Polycarbonate resin “Z300” (manufactured by Mitsubishi Gas Chemical) 300 parts by massAntioxidant: “Irganox 1010” ( 6 parts by mass / solvent: 1600 parts by mass of tetrahydrofuran / solvent: 400 parts by mass of toluene / leveling agent: silicone oil “KF-54” (manufactured by Shin-Etsu Chemical) 1 part by mass on the charge generation layer [1] Then, the charge transport layer forming coating solution [1] is applied using a circular slide hopper coating device to form a coating film, and the coating film is dried to form a charge transport layer [1] having a layer thickness of 28 μm. Formed.

(5) Formation of surface layer / polymerizable compound: monomer having an alkoxysilane structure represented by the above formula (1)
100 parts by mass / metal oxide fine particles [1] 15 parts by mass / solvent: 2-butanol 400 parts by mass / solvent: tetrahydrofuran 40 parts by mass A mixture of 5 parts by shading as a disperser for 5 hours. After dispersing
-Electron transfer agent: 40 parts by mass of the compound represented by the formula (A1)-Photobase generator: "WPBG-266" (manufactured by Wako Pure Chemical Industries, Ltd.) 10 parts by mass-3 parts by mass of pure water Under stirring, the mixture was dissolved to prepare a surface layer forming coating solution [1].
By applying this surface layer forming coating solution [1] onto the charge transport layer [1] using a circular slide hopper coating device to form a coating film, and then irradiating ultraviolet rays for 1 minute using a metal halide lamp Then, a surface layer [1] having a dry film thickness of 3.5 μm was formed, whereby a photoreceptor [1] was produced.

[Examples 2 to 10, Comparative Examples 1 to 5: Photoconductor Preparation Examples 2 to 15]
Photoreceptors [2] to [15] were produced in the same manner as in the surface layer forming step in Production Example 1 of Photoreceptor except that the prescription in Table 1 was followed.
In addition, the metal oxide fine particles [6] used in Comparative Examples 4 and 5 in Table 1 are “SFP-20M” (average primary particle size: 30 nm, manufactured by Denki Kagaku Kogyo).
The polymerizable compound used in Comparative Examples 4 and 5 in Table 1 is a compound represented by the following formula (6).
Moreover, the charge transport agent used in Comparative Example 2 in Table 1 is a compound (hole transport agent) represented by the following formula (B).

  The above photoconductors [1] to [15] are mounted on an evaluator: the image forming unit of the image forming apparatus “bizhub C554” (manufactured by Konica Minolta Co., Ltd.) in which the charging means is modified to the contact charging method. Evaluation was performed. The results are shown in Table 2.

(1) Durability evaluation (depletion)
After printing 30,000 character charts corresponding to a printing rate of 5%, the film thickness of the surface layer of the photoreceptor was measured, the amount of wear of the surface layer was calculated, and evaluated according to the following evaluation criteria. The film thickness was measured using an eddy current film thickness measuring instrument “Fischer Scope MMS PC” (manufactured by Fisher Instruments).
-Evaluation criteria-
A: When the amount of wear is within 0.3 μm (pass)
B: When the amount of wear is greater than 0.3 μm and within 0.6 μm (pass)
C: When the amount of wear is larger than 0.6 μm and within 1.0 μm (failed)
D: When the amount of wear is greater than 1.0 μm (failed)

(2) Evaluation of image quality (2-1) Evaluation of image unevenness A character chart corresponding to a printing rate of 5% was continuously printed on 100,000 sheets of A3 paper by an evaluation machine. Thereafter, a chart having a patch portion C with a black solid image and an image portion B with a halftone image as shown in FIG. 3 is printed on one sheet of A3 paper, and this halftone image is visually observed. The image quality was evaluated according to the evaluation criteria.
-Evaluation criteria-
A: When almost no degradation of the quality of the halftone image is confirmed (pass)
B: When a slight deterioration in the quality of the halftone image is confirmed (pass)
C: When deterioration of the quality of the halftone image is confirmed (failed)
D: A level at which the quality of the halftone image is significantly deteriorated and causes a practical problem (fail)

(2-2) Evaluation of graininess By using an evaluation machine, a character chart corresponding to a printing rate of 5% is continuously applied to 2000 sheets of A3 paper in a high temperature and high humidity (temperature 30 ° C., relative humidity 85%) environment. Printed. Thereafter, a halftone image (reference halftone image) was printed on one sheet of A3 paper. Thereafter, the evaluation machine was turned off and allowed to stand for 8 hours. Then, the evaluation machine was turned on again, and halftone images were continuously printed on 20 sheets of A3 paper. The printed halftone image (test halftone image) was visually observed in comparison with the reference halftone image, and the image quality was evaluated according to the following evaluation criteria.
-Evaluation criteria-
A: When the quality of the test halftone image is equivalent to the quality of the reference halftone image (pass)
B: When the quality of the test halftone image is slightly deteriorated compared to the quality of the reference halftone image (pass)
C: When the quality of the test halftone image is deteriorated compared to the quality of the reference halftone image (failed)
D: Level at which the quality of the test halftone image is significantly deteriorated compared to the quality of the reference halftone image, causing a practical problem (fail)

(2-3) Evaluation of Image Density After a character chart corresponding to a printing rate of 5% was continuously printed on 100,000 sheets of A3 paper by an evaluator, a halftone image was printed on one sheet of A3 paper. . Thereafter, the surface of the photoreceptor mounted on the evaluation machine was visually observed. Further, the presence or absence of image defects in the printed halftone image was visually observed. Then, according to the following evaluation criteria, the correlation between the surface state of the photoreceptor and the presence or absence of image defects in the halftone image was evaluated. In this evaluation, if the generation of streaks and filming (for example, the remaining image developer or external additive) is not confirmed on the surface of the photoreceptor, it can be said that the hardness of the surface layer of the photoreceptor is high. The image defect is generated in correlation with the occurrence of filming.
-Evaluation criteria-
A: When the generation of streaks and filming is not confirmed on the surface of the photoconductor, and the occurrence of image defects is not confirmed in the halftone image (pass).
B: When the generation of streaks and filming is confirmed on the surface of the photoconductor but no image defect is confirmed in the halftone image (pass)
C: When the occurrence of streaks and filming is confirmed on the surface of the photosensitive member, and the occurrence of image defects is confirmed in the halftone image (fail).
D: Level at which streaks and filming are confirmed on the surface of the photoconductor, and image defects are noticeably generated in the halftone image, causing a practical problem (fail).

1a Conductive support 1b Intermediate layer 1c Charge generation layer 1d Charge transport layer 1e Protective layer 1eA Specific metal oxide fine particles 1f Photosensitive layers 1Y, 1M, 1C, 1Bk Photoconductors 2Y, 2M, 2C, 2Bk Charging means 3Y, 3M , 3C, 3Bk Exposure means 4Y, 4M, 4C, 4Bk Developing means 5Y, 5M, 5C, 5Bk Primary transfer roller 5b Secondary transfer rollers 6Y, 6M, 6C, 6Bk, 6b Cleaning means 10Y, 10M, 10C, 10Bk Image formation Unit 20 Paper feed cassette 21 Paper feed means 22A, 22B, 22C, 22D Intermediate roller 23 Registration roller 24 Fixing means 25 Paper discharge roller 26 Paper discharge tray 70 Intermediate transfer body units 71, 72, 73, 74 Roller 77 Intermediate transfer body 80 Cases 82L, 82R Support rail A Main body SC Document image reading device P Transfer material

Claims (8)

An electrophotographic photosensitive member in which an intermediate layer, a photosensitive layer and a surface layer are laminated in this order on a conductive support,
From a cured product of a composition in which the surface layer contains a monomer having an alkoxysilane structure, metal oxide fine particles having a reactive organic group that reacts with a group other than the polymerizable reactive group in the monomer, and an electron transport agent. An electrophotographic photoreceptor characterized by comprising: The metal oxide fine particles, SnO _2, electrophotographic photosensitive member according to claim 1, characterized by comprising at least than one selected from the group consisting of SiO ₂ and Al ₂ O _3. The electrophotographic photosensitive member according to claim 1, wherein the electron transfer agent comprises a compound having a naphthoquinone structure represented by the following general formula (1).

[Wherein, R ¹ and R ² each independently represent an alkyl group having 1 to 6 carbon atoms, and n is 0 or 1. ]   4. The electrophotographic photosensitive member according to claim 1, wherein the total thickness of the photosensitive layer and the surface layer is 20 [mu] m or less.   The electrophotographic photosensitive member according to claim 1, wherein the surface layer has a layer thickness of 4 μm or less. An electrophotographic photosensitive member, a proximity charging type charging unit that charges the surface of the electrophotographic photosensitive member, an exposure unit that exposes the electrophotographic photosensitive member charged by the charging unit, and an electron that is exposed by the exposing unit An image forming apparatus comprising: a developing unit that supplies toner to a photographic photosensitive member to form a toner image;
An image forming apparatus, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 1 to 5.   The image forming apparatus according to claim 6, wherein the proximity charging type charging unit includes a charging member that contacts the surface layer. The image forming apparatus according to claim 7, wherein the charging member applies an alternating voltage in a superimposed manner.