JP2014149502A - Image forming apparatus, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form images having excellent resolution and gradation.SOLUTION: An image forming apparatus 101 includes: an electrophotographic photoreceptor 7 provided with a conductive base material, an undercoat layer containing a metal oxide and an anthraquinone derivative, a photosensitive layer, and a surface protective layer containing a polymer polymerized with a reactive charge transport material; a charging device 8; an exposure device 10; a developing device 11 that develops an electrostatic latent image formed on the surface of the electrophotographic photoreceptor 7 with a developer including a toner having a volume average particle diameter of 4.0 μm or less to form a toner image; a transfer device 12 that transfers the toner image to a recording medium P; and an electricity eliminating device 14 that charges the electrophotographic photoreceptor 7 after the transfer of the toner image by the transfer device 12 with a current controlled at a constant current of 250 μA or more and 350 μA or less, and subsequently exposes the electrophotographic photoreceptor 7 to eliminate electricity.

Description

  The present invention relates to an image forming apparatus and a process cartridge.

  Electrophotographic image forming apparatuses are used in image forming apparatuses such as copying machines and laser beam printers.

For example, in Patent Document 1, an electrostatic latent image holding member, an electrostatic latent image forming unit that forms an electrostatic latent image on the electrostatic latent image holding member, and the electrostatic latent image using toner. An external additive comprising at least developing means for developing and forming a toner image and transfer means for transferring the toner image to a recording medium, wherein the toner includes particles having an average particle diameter Da of 100 nm to 300 nm. And the average value F of the non-electrostatic adhesion force between the toner and the electrostatic latent image carrier, the volume average particle diameter Dt of the toner, and the average particle diameter Da of the external additive. An image forming apparatus in which a value [F / (Dt × Da)] divided by the product is 7.5 × 10 ⁴ N / m ² or less is disclosed.

JP 2007-034268 A

  An object of the present invention is to provide an image forming apparatus capable of forming an image excellent in resolution and gradation.

The above problem is solved by the following means. That is,
The invention according to claim 1
A conductive substrate, an undercoat layer containing a metal oxide and an anthraquinone derivative coordinated to the metal oxide, a photosensitive layer, and a surface protective layer containing a polymer obtained by polymerizing a reactive charge transport material; And an electrophotographic photosensitive member comprising in this order,
A charging device for charging the surface of the electrophotographic photosensitive member;
An exposure device that exposes a surface of the charged electrophotographic photosensitive member to form an electrostatic latent image; and
A developer holding body that contains a developer containing a toner having a volume average particle size of 4.0 μm or less and that holds the developer on the surface, and the developer held on the surface of the developer holding body, A developing device that develops an electrostatic latent image formed on the surface of the electrophotographic photosensitive member to form a toner image;
A transfer device for transferring a toner image formed on the surface of the electrophotographic photosensitive member to a recording medium;
A static eliminator that charges the electrophotographic photosensitive member after the toner image is transferred by the transfer device at a constant current controlled current of 250 μA or more and 350 μA or less, and then exposes and eliminates the static electricity;
An image forming apparatus.

The invention according to claim 2
The image forming apparatus according to claim 1, wherein the anthraquinone derivative has a structure represented by the following general formula (1).

(In general formula (1), n1 and n2 each independently represent an integer of 0 or more and 3 or less, provided that at least one of n1 and n2 represents an integer of 1 or more and 3 or less (that is, n1 and n2 are M1 and m2 each independently represent an integer of 0 or 1. R ¹ and R ² each independently represents an alkyl group having 1 to 10 carbon atoms, or 1 to 10 carbon atoms. Represents the following alkoxy group.)

The invention according to claim 3
A conductive substrate, an undercoat layer containing a metal oxide and an anthraquinone derivative coordinated to the metal oxide, a photosensitive layer, and a surface protective layer containing a polymer obtained by polymerizing a reactive charge transport material; And an electrophotographic photosensitive member comprising in this order,
A developer holding body that contains a developer containing a toner having a volume average particle size of 4.0 μm or less and that holds the developer on the surface is formed, and an electrostatic latent image is formed on the surface of the electrophotographic photosensitive member. A developing device for developing the electrostatic latent image with the developer held on the surface of the developer holder to form a toner image;
A charge eliminating device that charges the electrophotographic photosensitive member after transferring the toner image to a recording medium with a constant current controlled current of 250 μA or more and 350 μA or less, and then exposes and removes the charge.
It is a process cartridge that can be attached to and detached from the image forming apparatus.

The invention according to claim 4
The process cartridge according to claim 3, wherein the anthraquinone derivative has a structure represented by the following general formula (1).

(In general formula (1), n1 and n2 each independently represent an integer of 0 or more and 3 or less, provided that at least one of n1 and n2 represents an integer of 1 or more and 3 or less (that is, n1 and n2 are M1 and m2 each independently represent an integer of 0 or 1. R ¹ and R ² each independently represents an alkyl group having 1 to 10 carbon atoms, or 1 to 10 carbon atoms. Represents the following alkoxy group.)

  According to the first aspect of the present invention, it comprises an undercoat layer containing a metal oxide and an anthraquinone derivative coordinated to the metal oxide, and a surface protective layer containing a polymer obtained by polymerizing a reactive charge transport material. An electrophotographic photosensitive member, a developing device containing a developer containing a toner having a volume average particle size of 4.0 μm or less, and the electrophotographic photosensitive member is charged with a constant current controlled current of 250 μA or more and 350 μA or less, and thereafter There is provided an image forming apparatus capable of forming an image having excellent resolution and gradation as compared with a case where any one of the static elimination apparatuses that perform static elimination by exposure.

  According to the second aspect of the present invention, there is provided an image forming apparatus capable of forming an image having excellent gradation as compared with the case where the anthraquinone derivative does not have the structure represented by the general formula (1).

  According to the invention of claim 3, it comprises an undercoat layer containing a metal oxide and an anthraquinone derivative coordinated to the metal oxide, and a surface protective layer containing a polymer obtained by polymerizing a reactive charge transport material. An electrophotographic photosensitive member, a developing device containing a developer containing a toner having a volume average particle size of 4.0 μm or less, and the electrophotographic photosensitive member is charged with a constant current controlled current of 250 μA or more and 350 μA or less, and thereafter There is provided a process cartridge capable of forming an image having excellent resolution and gradation as compared with a case where any one of the static elimination apparatuses that perform static elimination by exposure.

  According to the fourth aspect of the present invention, there is provided a process cartridge capable of forming an image having excellent gradation as compared with the case where the anthraquinone derivative does not have the structure represented by the general formula (1).

1 is a schematic configuration diagram illustrating an image forming apparatus according to an exemplary embodiment. It is the schematic which shows an example of the layer structure of the electrophotographic photoreceptor in this embodiment. It is the schematic which shows the other example of the layer structure of the electrophotographic photoreceptor in this embodiment. It is a figure which shows the image pattern output in the Example. It is a figure which shows the image pattern output in the Example.

  Embodiments that are examples of the present invention will be described below.

The image forming apparatus according to this embodiment forms an electrostatic latent image by exposing an electrophotographic photosensitive member, a charging device that charges the surface of the electrophotographic photosensitive member, and the charged surface of the electrophotographic photosensitive member. An exposure device for developing, a developing device for developing the electrostatic latent image to form a toner image, a transfer device for transferring the toner image formed on the surface of the electrophotographic photosensitive member to a recording medium, and the transfer device. And a charge eliminating device that charges the electrophotographic photosensitive member after transferring the toner image and thereafter exposes the charge to remove electricity.
The electrophotographic photoreceptor includes a conductive substrate, an undercoat layer, a photosensitive layer, and a surface protective layer in this order, and the undercoat layer has a metal oxide and an anthraquinone derivative coordinated to the metal oxide. Containing. The surface protective layer contains a polymer obtained by polymerizing a reactive charge transport material.
Further, the developing device has a developer holding body that contains a developer containing toner having a volume average particle size of 4.0 μm or less and holds the developer on the surface, and is held on the surface of the developer holding body. The electrostatic latent image formed on the surface of the electrophotographic photosensitive member is developed with the developer thus formed to form a toner image.
Further, the static eliminator is an apparatus that charges the electrophotographic photosensitive member with a constant current controlled current of 250 μA or more and 350 μA or less, and thereafter exposes the electrophotographic photosensitive member to eliminate the charge.

  The process cartridge according to the present embodiment includes the electrophotographic photosensitive member, the developing device, and the charge eliminating device, and is attached to and detached from the image forming apparatus.

When a toner having a small average particle diameter of 4.0 μm or less is used, an image with higher resolution can be obtained as compared with a case where a toner having an average particle diameter larger than 4.0 μm is used. In addition, the surface protective layer containing a polymer obtained by polymerizing the reactive charge transporting material suppresses the wear of the photoconductor, thereby suppressing the occurrence of image quality defects such as fogging and black spots over a long period of time.
However, when the same image is continuously formed repeatedly, a difference in image density occurs depending on the presence or absence of exposure history, and a burn-in ghost may occur.

  On the other hand, in the present embodiment, the occurrence of seizure ghost can be suppressed by setting the applied current value at the time of charging by the static eliminator to 250 μA or more and 350 μA or less. Conventionally, the applied current value at the time of charging by the static eliminator is usually about 100 μA. On the other hand, the amount of passing carriers in the electrophotographic photosensitive member is increased by increasing to the above range, and the accumulated carriers with and without exposure history are recorded. The difference in amount is considered to be small, and it is assumed that seizure ghosts are suppressed.

  However, by increasing the applied current value at the time of charging by the static eliminator, the generation of the residual potential tends to become more prominent. An increase in the amount of passing carriers has a correlation with an increase in the residual potential on the surface of the electrophotographic photosensitive member, and the development electric field decreases as the potential after exposure increases. As a result, even when an image with excellent resolution can be obtained by using a small diameter toner having a volume average particle size of 4.0 μm or less, the gradation is sometimes inferior, and it is not easy to maintain high image quality.

  In contrast to this, in this embodiment, by using a metal oxide and a compound having an anthraquinone derivative coordinated with it in the undercoat layer of the electrophotographic photosensitive member, generation of residual potential is suppressed, and resolution over a long period of time. In addition, an image having excellent gradation can be formed.

Hereinafter, the image forming apparatus according to the present embodiment will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present exemplary embodiment.

  For example, as shown in FIG. 1, the image forming apparatus 101 according to the present embodiment includes a drum-shaped (cylindrical) electrophotographic photosensitive member 7 of the present embodiment that is rotatably provided. Around the electrophotographic photosensitive member 7, for example, along the moving direction of the outer peripheral surface of the electrophotographic photosensitive member 7, the charging device 8, the exposure device 10, the developing device 11, the transfer device 12, the cleaning device 13, and the static eliminating device 14. Are arranged in this order. The neutralization device 14 includes a charging member 14A and a neutralization exposure member 14B. The cleaning device 13 may not be arranged.

-Electrophotographic photoreceptor-
2 and 3 are schematic views showing examples of the layer structure of the photoreceptor according to the present embodiment. 2 includes a conductive substrate 1, an undercoat layer 2 formed on the conductive substrate 1, a photosensitive layer 3 formed on the undercoat layer 2, and a photosensitive layer 3. And a surface protective layer 5 formed on the substrate. Further, as shown in FIG. 3, the photosensitive layer 3 may have a two-layer structure of a charge generation layer 31 and a charge transport layer 32.

  A separate intermediate layer may be provided between the undercoat layer 2 and the photosensitive layer 3 or between the undercoat layer 2 and the charge generation layer 31. Furthermore, the intermediate layer may be provided between the conductive substrate 1 and the undercoat layer 2, or of course, an embodiment in which the intermediate layer is not provided may be employed.

  Next, each element of the electrophotographic photoreceptor will be described. Note that the reference numerals are omitted.

(Conductive substrate)
Any conductive substrate may be used as long as it is conventionally used. For example, thin films (eg, metals such as aluminum, nickel, chromium, and stainless steel, and films such as aluminum, titanium, nickel, chromium, stainless steel, gold, vanadium, tin oxide, indium oxide, and indium tin oxide (ITO)) And a plastic film coated or impregnated with a conductivity imparting agent, a plastic film coated or impregnated with a conductivity imparting agent, and the like. The shape of the substrate is not limited to a cylindrical shape, and may be a sheet shape or a plate shape.

  When a metal pipe is used as the conductive base material, the surface may remain as it is, or a process such as mirror cutting, etching, anodizing, rough cutting, centerless grinding, sand blasting, wet honing, etc. is performed in advance. May be.

(Undercoat layer)
−Configuration−
The undercoat layer includes a metal oxide and an anthraquinone derivative. By containing a metal oxide and an anthraquinone derivative coordinated therewith, generation of a residual potential is suppressed. Furthermore, a binder resin or the like may be included.

-Metal oxide Examples of the metal oxide include particles of antimony oxide, indium oxide, tin oxide, titanium oxide, zinc oxide and the like.
Among these, as the metal oxide, particles of tin oxide, titanium oxide, and zinc oxide are preferable from the viewpoint of fine line reproducibility and suppression of increase in residual potential.

As the metal oxide, a conductive powder having a particle diameter of 100 nm or less, particularly 10 nm or more and 100 nm or less is desirably used. The particle size here means an average primary particle size. The average primary particle size of the metal oxide is a value observed and measured by SEM (scanning electron microscope).
When the particle size of the metal oxide is 10 nm or more, the surface area of the metal oxide does not become too large, and the occurrence of unevenness in the dispersion is suppressed. On the other hand, when the particle size of the metal oxide is 100 nm or less, secondary particles or higher particles are effectively suppressed from having a particle size of about 1 μm, and the metal oxide is oxidized in the undercoat layer. It is possible to suppress a portion where an object exists and a portion where an object does not exist, that is, a so-called sea-island structure, thereby suppressing the occurrence of image quality defects such as uneven halftone density.

The metal oxide is preferably a powder resistance of 10 ⁴ Ω · cm to 10 ¹⁰ Ω · cm. As a result, it becomes easy for the undercoat layer to obtain an appropriate impedance at a frequency corresponding to the electrophotographic process speed.

The metal oxide is preferably surface-treated with at least one coupling agent for the purpose of improving various properties such as dispersibility.
The coupling agent may be at least one selected from silane coupling agents, titanate coupling agents, and aluminate coupling agents.
Specific examples of coupling agents include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycid. Xylpropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (amino Silane coupling agents such as ethyl) -γ-aminopropylmethyldimethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, acetoalkoxyaluminum diisopropyl Aluminum such as rate Titanate coupling agents, isopropyl triisostearoyl titanate, bis (dioctyl pyrophosphate), titanate coupling agents such as isopropyl tri (N-aminoethyl-aminoethyl) titanate, and the like. It is not something. Moreover, you may use these coupling agents in mixture of 2 or more types.

  The treatment amount of the coupling agent is preferably 0.1% by mass or more and 3% by mass or less with respect to the metal oxide, desirably 0.3% by mass or more and 2.0% by mass or less, and more desirably 0%. 0.5 mass% or more and 1.5 mass% or less.

In addition, the processing amount of a coupling agent is measured as follows.
There are analysis methods such as FT-IR method, 29Si solid state NMR method, thermal analysis, XPS, etc., but FT-IR method is the simplest. In the FT-IR method, the normal KBr tablet method or the ATR method may be used. A small amount of the treated metal oxide is mixed with KBr and the FT-IR is measured to measure the coupling agent throughput.

  The metal oxide may be subjected to heat treatment after surface treatment with the above coupling agent in order to improve the environmental dependency of the resistance value. The heat treatment temperature is preferably, for example, 150 ° C. or more and 300 ° C. or less, and the treatment time is 30 minutes or more and 5 hours or less.

  The content of the metal oxide is preferably 30% by mass or more and 60% by mass or less, and more preferably 35% by mass or more and 55% by mass or less from the viewpoint of maintaining electrical characteristics.

Anthraquinone derivative An anthraquinone derivative is a material that chemically reacts with the surface of the metal oxide contained in the undercoat layer, or a material that adsorbs to the surface of the metal oxide, and can selectively exist on the surface of the metal oxide. .
As the anthraquinone derivative, a compound represented by the following general formula (1) is desirable from the viewpoint of fine line reproducibility and suppression of increase in residual potential.

In general formula (1), n1 and n2 each independently represent an integer of 0 or more and 3 or less. However, at least one of n1 and n2 represents an integer of 1 or more and 3 or less (that is, n1 and n2 do not simultaneously represent 0). m1 and m2 each independently represents an integer of 0 or 1. R ¹ and R ² each independently represents an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms.

Among the anthraquinone derivatives represented by the general formula (1), a compound in which at least one of R ¹ and R ² represents an alkoxy group having 1 to 10 carbon atoms is preferable from the viewpoint of fine line reproducibility and suppression of increase in residual potential. Note that at least one of m1 and m2 is preferably 1.

Here, in the general formula (1), the alkyl group having 1 to 10 carbon atoms represented by R ¹ and R ² may be linear or branched. For example, a methyl group, an ethyl group, A propyl group, an isopropyl group, etc. are mentioned. The alkyl group having 1 to 10 carbon atoms is preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms.
The alkoxy group having 1 to 10 carbon atoms (alkoxyl group) represented by R ¹ and R ² may be either linear or branched, for example, methoxy group, ethoxy group, propoxy group, isopropoxy group , Butoxy group, octoxy group and the like. The alkoxy group having 1 to 10 carbon atoms is preferably an alkoxyl group having 1 to 8 carbon atoms, more preferably an alkoxyl group having 1 to 6 carbon atoms.

  Moreover, as an anthraquinone derivative, the compound represented by following General formula (2) may be sufficient.

In general formula (2), n1, n2, n3, and n4 each independently represent an integer of 0 or more and 3 or less. However, at least one of n1 and n2 represents an integer of 1 or more and 3 or less (that is, n1 and n2 do not simultaneously represent 0). At least one of n3 and n4 represents an integer of 1 or more and 3 or less (that is, n3 and n4 do not represent 0 at the same time). m1 and m2 each represents an integer of 0 or 1. R ¹ and R ² each independently represents an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms. r represents an integer of 1 or more and 10 or more.

Here, in the general formula (2), the alkyl group having 1 to 10 carbon atoms represented by R ¹ and R ² may be linear or branched. For example, a methyl group, an ethyl group, A propyl group, an isopropyl group, etc. are mentioned. The alkyl group having 1 to 10 carbon atoms is preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms.
The alkoxy group having 1 to 10 carbon atoms (alkoxyl group) represented by R ¹ and R ² may be either linear or branched, for example, methoxy group, ethoxy group, propoxy group, isopropoxy group , Butoxy group, octoxy group and the like. The alkoxy group having 1 to 10 carbon atoms is preferably an alkoxyl group having 1 to 8 carbon atoms, more preferably an alkoxyl group having 1 to 6 carbon atoms.
r is preferably 2 or more and 10 or less.

Here, specific examples of the anthraquinone derivative are shown below. However, it is not limited to these.
In addition, the following specific example compound is called "exemplary compound" below, for example, if it is a compound of the following (1-1), it will be called "exemplary compound (1-1)."

The content of the anthraquinone derivative is determined from the surface area and content of the metal oxide that is a chemical reaction or adsorption partner, and the electron transport ability of each material, but is usually 0.01% by mass or more and 20% in the undercoat layer. The range of mass% or less is good, and more desirably the range is 0.1 mass% or more and 10 mass% or less.
When the content of the anthraquinone derivative is 0.1% by mass or more, the effect of the acceptor substance is efficiently expressed. Moreover, when the content of the anthraquinone derivative is 20% by mass or less, aggregation of the metal oxides is suppressed, uneven distribution in the metal oxide undercoat layer is suppressed, and a good conductive path is formed. Is done.

-Binder resin As the binder resin, for example, acetal resin (for example, polyvinyl butyral), polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride Examples thereof include polymer resin compounds such as resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, phenol resins, phenol-formaldehyde resins, and melamine resins.

Other additives Examples of other additives include resin particles. When coherent light such as a laser is used for the exposure apparatus, it is preferable to prevent moiré images. for that purpose. The surface roughness of the undercoat layer is preferably adjusted to ¼n (n is the refractive index of the upper layer) or more and ½λ or less of the exposure laser wavelength λ to be used. Therefore, when the resin particles are added to the undercoat layer, the surface roughness can be adjusted. Examples of the resin particles include silicone resin particles and cross-linked polymethyl methacrylate (PMMA) resin.
Further, the other additives are not limited to the above, and well-known additives are also included.

-Formation of undercoat layer-
In forming the undercoat layer, a coating solution for forming an undercoat layer in which the above components are added to a solvent is used. The coating solution for forming the undercoat layer can be obtained, for example, by dispersing a metal oxide, an anthraquinone derivative, and other additives or the like, which are premixed or predispersed, in a binder resin.
The solvent used for obtaining the coating solution for forming the undercoat layer is a known organic solvent that dissolves the above-mentioned binder resin, for example, alcohol, aromatic, halogenated hydrocarbon, ketone, ketone alcohol, ether. And ester solvents. These solvents may be used alone or in combination of two or more.
As a method for dispersing the metal oxide in the coating solution for forming the undercoat layer, a known dispersion method is used. Examples thereof include a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker.

  As a coating method for the coating solution for forming the undercoat layer, known coating methods such as a dip coating method, a blade coating method, a wire bar coating method, a spray coating method, a bead coating method, an air knife coating method, and a curtain coating method are used.

  The undercoat layer preferably has a Vickers strength of 35 to 50.

  The thickness of the undercoat layer is preferably 15 μm or more, more preferably 15 μm or more and 30 μm or less, and further preferably 20 μm or more and 25 μm or less from the viewpoint of improving the graininess of the image.

(Middle layer)
The intermediate layer may be provided, for example, between the undercoat layer and the photosensitive layer in order to improve electrical characteristics, improve image quality, improve image quality maintenance, and improve photosensitive layer adhesion. The intermediate layer may be provided between the conductive base material and the undercoat layer.

  As the binder resin used for the intermediate layer, acetal resin (for example, polyvinyl butyral), polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin In addition to polymer resin compounds such as polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin, zirconium, titanium, aluminum, manganese, silicon And organometallic compounds containing atoms. These compounds may be used alone or as a mixture or polycondensate of a plurality of compounds. Among these, an organometallic compound containing zirconium or silicon is preferable in that it has a low residual potential, a small potential change due to the environment, and a small potential change due to repeated use.

In forming the intermediate layer, a coating solution for forming an intermediate layer in which the above components are added to a solvent is used.
As the coating method for forming the intermediate layer, usual methods such as a dip coating method, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, and a curtain coating method are used.

  In addition to improving the coatability of the upper layer, the intermediate layer also serves as an electrical blocking layer. However, if the film thickness is too large, the electrical barrier becomes too strong and the potential increases due to desensitization or repetition. May cause. Therefore, when forming the intermediate layer, it is preferable to set the film thickness within the range of 0.1 μm to 3 μm. In this case, the intermediate layer may be used as the undercoat layer.

(Charge generation layer)
The charge generation layer includes, for example, a charge generation material and a binder resin. The charge generation layer may be composed of a vapor deposition film of a charge generation material.
Examples of the charge generation material include phthalocyanine pigments such as metal-free phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, dichlorotin phthalocyanine, and titanyl phthalocyanine, and in particular, have a Bragg angle (2θ ± 0.2 °) with respect to CuKα characteristic X-rays. Chlorogallium phthalocyanine crystal having strong diffraction peaks at least at 7.4 °, 16.6 °, 25.5 ° and 28.3 °, Bragg angle (2θ ± 0.2 °) to CuKα characteristic X-ray of at least 7. Metal-free phthalocyanine crystals having strong diffraction peaks at 7 °, 9.3 °, 16.9 °, 17.5 °, 22.4 ° and 28.8 °, Bragg angle (2θ ± 0. 2 °) at least 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, Hydroxygallium phthalocyanine crystals with strong diffraction peaks at 5.1 ° and 28.3 °, Bragg angles (2θ ± 0.2 °) to CuKα characteristic X-rays of at least 9.6 °, 24.1 ° and 27.2 A titanyl phthalocyanine crystal having a strong diffraction peak at 0 ° can be mentioned. In addition, examples of the charge generation material include quinone pigments, perylene pigments, indigo pigments, bisbenzimidazole pigments, anthrone pigments, quinacridone pigments, and the like. These charge generation materials may be used alone or in combination of two or more.

  Examples of the binder resin constituting the charge generation layer include polycarbonate resin such as bisphenol A type or bisphenol Z type, acrylic resin, methacrylic resin, polyarylate resin, polyester resin, polyvinyl chloride resin, polystyrene resin, acrylonitrile-styrene. Copolymer resin, acrylonitrile-butadiene copolymer, polyvinyl acetate resin, polyvinyl formal resin, polysulfone resin, styrene-butadiene copolymer resin, vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride Examples thereof include resins, silicone resins, phenol-formaldehyde resins, polyacrylamide resins, polyamide resins, poly-N-vinylcarbazole resins. These binder resins may be used alone or in combination of two or more.

  The mixing ratio of the charge generating material and the binder resin is preferably in the range of 10: 1 to 1:10, for example.

When forming the charge generation layer, a coating solution for forming a charge generation layer in which the above components are added to a solvent is used.
As a method for dispersing particles (for example, charge generation material) in the coating solution for forming the charge generation layer, a media dispersion machine such as a ball mill, a vibration ball mill, an attritor, a sand mill, a horizontal sand mill, an agitation, an ultrasonic dispersion machine, a roll mill, etc. Medialess dispersers such as high-pressure homogenizers are used. Examples of the high-pressure homogenizer include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision in a high-pressure state, and a penetration method in which a fine flow path is dispersed in a high-pressure state.

  Examples of the method for applying the charge generation layer forming coating liquid on the undercoat layer include dip coating, push-up coating, wire bar coating, spray coating, blade coating, knife coating, and curtain coating. It is done.

  The thickness of the charge generation layer is desirably set in the range of 0.01 μm to 5 μm, more desirably 0.05 μm to 2.0 μm.

(Charge transport layer)
The charge transport layer includes, for example, a charge transport material, a binder resin, and the like.
Examples of the charge transport material include oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1- [ Pyrazoline derivatives such as pyridyl- (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminostyryl) pyrazoline, triphenylamine, N, N′-bis (3,4-dimethylphenyl) biphenyl- Aromatic tertiary amino compounds such as 4-amine, tri (p-methylphenyl) aminyl-4-amine, dibenzylaniline, N, N′-bis (3-methylphenyl) -N, N′-diphenylbenzidine Aromatic tertiary diamino compounds such as 3- (4′-dimethylaminophenyl) -5,6-di- (4′-methoxyphenyl) -1,2,4-tri 1,2,4-triazine derivatives such as gin, hydrazone derivatives such as 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, 6-hydroxy-2,3- Benzofuran derivatives such as di (p-methoxyphenyl) benzofuran, α-stilbene derivatives such as p- (2,2-diphenylvinyl) -N, N-diphenylaniline, enamine derivatives, carbazole derivatives such as N-ethylcarbazole, poly -Hole transport materials such as -N-vinylcarbazole and its derivatives, quinone compounds such as chloranil and broanthraquinone, tetraanoquinodimethane compounds, 2,4,7-trinitrofluorenone, 2,4,5,7 -Fluorenone compounds such as tetranitro-9-fluorenone , Xanthone compounds, electron transporting material, such as a thiophene compound, and a polymerization products thereof having a group consisting of the compounds described above in the main chain or side chain. These charge transport materials may be used alone or in combination of two or more.

Examples of the binder resin constituting the charge transport layer include polycarbonate resin such as bisphenol A type or bisphenol Z type, acrylic resin, methacrylic resin, polyarylate resin, polyester resin, polyvinyl chloride resin, polystyrene resin, acrylonitrile-styrene. Copolymer resin, acrylonitrile-butadiene copolymer resin, polyvinyl acetate resin, polyvinyl formal resin, polysulfone resin, styrene-butadiene copolymer resin, vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-vinyl acetate-anhydrous maleic acid Insulating resins such as acid resins, silicone resins, phenol-formaldehyde resins, polyacrylamide resins, polyamide resins, chlorinated rubber, and polyvinyl carbazole and polyvinyl ant Sen, organic photoconductive polymers such as polyvinyl pyrene, and the like. These binder resins may be used alone or in combination of two or more.
The mixing ratio between the charge transport material and the binder resin is preferably 10: 1 to 1: 5, for example.

The charge transport layer is formed using a charge transport layer forming coating solution in which the above components are added to a solvent.
As a method for applying the charge transport layer forming coating solution on the charge generation layer, dip coating method, push-up coating method, wire bar coating method, spray coating method, blade coating method, knife coating method, curtain coating method, etc. The method is used.

  The film thickness of the charge transport layer is desirably set in the range of 5 μm to 50 μm, more desirably 10 μm to 40 μm.

-Surface protective layer The surface protective layer 5 contains the polymer by which the reactive charge transport material was polymerized.

[Polymer obtained by polymerizing reactive charge transport material]
The charge transport material to be polymerized is a charge transport material having at least one reactive functional group. For example, as the reactive functional group, -OH, -OR (R is an alkyl group having 1 to 18 carbon atoms), -NH _2, -SH, -COOH, and the like. Preferred are those having at least two of these reactive functional groups, and more preferred are those having three or more.

  Among them, a reactive charge transport material having a hydroxyl group (—OH) as a reactive group and a reactive charge having an alkoxy group (—OR (R is an alkyl group having 1 to 18 carbon atoms)) as a reactive group. It is desirable to use at least two kinds of reactive charge transport materials together with the transport material.

As the charge transport material having a reactive functional group, a compound represented by the following general formula (I) is particularly desirable.
_{^{F - ((- R 7 -X}} ) n1 (R 8) n3 -Y) n2 (I)
In general formula (I), F represents an organic group derived from a compound having a hole transporting ability, and R ⁷ and R ⁸ are each independently a linear or branched alkylene having 1 to 5 carbon atoms. N1 represents 0 or 1, n2 represents an integer of 1 or more and 4 or less, and n3 represents 0 or 1. X represents an oxygen, NH, or sulfur atom, and Y represents —OH, —OR (R represents an alkyl group having 1 to 18 carbon atoms), —NH ₂ , —SH, or —COOH.

  In general formula (I), as the compound having a hole transport ability in an organic group derived from a compound having a hole transport ability represented by F, an arylamine derivative is preferably exemplified. Preferred examples of the arylamine derivative include a triphenylamine derivative and a tetraphenylbenzidine derivative.

  The compound represented by the general formula (I) is preferably a compound represented by the following general formula (II).

In general formula (II), Ar ^{1 to} Ar ⁴ may be the same or different and each independently represents a substituted or unsubstituted aryl group, and Ar ⁵ represents a substituted or unsubstituted aryl group or a substituted or unsubstituted group. D represents — (— R ⁷ —X) _n1 (R ⁸ ) _n3 —Y, c represents 0 or 1 independently, k represents 0 or 1, and the total number of D is 1 or more and 4 or less. R ⁷ and R ⁸ each independently represents a linear or branched alkylene group having 1 to 5 carbon atoms, n1 represents 0 or 1, n3 represents 0 or 1, and X represents oxygen , NH, or a sulfur atom, Y represents —OH, —OR (R represents an alkyl group having 1 to 18 carbon atoms), —NH ₂ , —SH, or —COOH.

In the general formula (II), “— (— R ⁷ —X) _n1 (R ⁸ ) _n3 —Y” representing D is synonymous with the general formula (I), and R ⁷ and R ⁸ are each independently carbon. A linear or branched alkylene group having a number of 1 or more and 5 or less.
In particular, n1 is preferably 0 and n3 is 1. In this case, R ⁸ is preferably a methylene group, an ethylene group or a propylene group, more preferably a methylene group. Y is more preferably -OH.

The total number of D in the general formula (II) corresponds to n2 in the general formula (I), preferably 2 or more and 4 or less, and more preferably 3 or more and 4 or less. That is, in the general formula (I) or the general formula (II), the above reactive functional groups (—OH, —OR (R is a carbon atom), preferably 2 or more and 4 or less, more preferably 3 or more and 4 or less in one molecule. It is desirable to have an alkyl group having a number of 1 or more and 18 or less, —NH ₂ , —SH, or —COOH).

In general formula (II), Ar ^{1 to} Ar ⁴ are preferably any of the following formulas (1) to (7). The following formulas (1) to (7) are shown together with “-(D) _c ” that can be linked to each of Ar ^{1 to} Ar ⁴ .

[In the formulas (1) to (7), R ⁹ is substituted with a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Represents one selected from the group consisting of a phenyl group, an unsubstituted phenyl group, and an aralkyl group having 7 to 10 carbon atoms, wherein R ^{10 to} R ¹² are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, carbon 1 selected from the group consisting of an alkoxy group having 1 to 4 carbon atoms, a phenyl group substituted with an alkoxy group having 1 to 4 carbon atoms, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom. Represents a seed, Ar represents a substituted or unsubstituted arylene group, D and c have the same meanings as “D” and “c” in formula (II), s represents 0 or 1, and t represents 1 3 or more It represents an integer. ]

  Here, as Ar in Formula (7), what is represented by following formula (8) or (9) is desirable.

[In formulas (8) and (9), R ¹³ and R ¹⁴ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. 1 represents one selected from the group consisting of a phenyl group substituted with, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms and a halogen atom, and t represents an integer of 1 to 3. ]

  Further, Z ′ in the formula (7) is preferably represented by any one of the following formulas (10) to (17).

[In the formulas (10) to (17), R ¹⁵ and R ¹⁶ are each a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. 1 represents one selected from the group consisting of a phenyl group substituted with, an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom, W represents a divalent group, q and r each represent Represents an integer of 1 to 10, and t represents an integer of 1 to 3. ]

  W in the formulas (16) to (17) is preferably any one of divalent groups represented by the following (18) to (26). However, in formula (25), u represents an integer of 0 or more and 3 or less.

In general formula (II), Ar ⁵ is the aryl group of the above (1) to (7) exemplified in the description of Ar ^{1 to} Ar ⁴ when k is 0, and when k is 1, An arylene group obtained by removing one hydrogen atom from the above aryl groups (1) to (7) is desirable.

  Specific examples of the compound represented by the general formula (I) include the following compounds. In addition, the compound shown by the said general formula (I) is not limited at all by these.

  The content of the charge transport material in all components (material remaining as a solid content) used for forming the surface protective layer is preferably 85% by mass or more, and the upper limit thereof is 98% by mass or less. Preferably there is. More preferably, it is 90 mass% or more and 95 mass% or less.

[Guanamine compounds, melamine compounds]
The polymer obtained by polymerizing the reactive charge transport material may be a crosslinked polymer further crosslinked with a compound having a guanamine structure or a melamine structure.

  A compound having a guanamine structure (guanamine compound) is a compound having a guanamine skeleton, and examples thereof include acetoguanamine, benzoguanamine, formoguanamine, steroguanamine, spiroguanamine, and cyclohexylguanamine.

  The guanamine compound is particularly preferably at least one of a compound represented by the following general formula (A) and a multimer thereof. Here, the multimer is an oligomer polymerized using the compound represented by the general formula (A) as a structural unit, and the degree of polymerization thereof is, for example, 2 or more and 200 or less (preferably 2 or more and 100 or less). In addition, the compound shown by general formula (A) may be used individually by 1 type, but may use 2 or more types together.

In General Formula (A), R ¹ is a linear or branched alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, or 4 to 10 carbon atoms. The following substituted or unsubstituted alicyclic hydrocarbon groups are shown. R ^{2 to} R ⁵ each independently represent hydrogen, —CH ₂ —OH, or —CH ₂ —O—R ⁶ . R ⁶ represents hydrogen or a linear or branched alkyl group having 1 to 10 carbon atoms.

In general formula (A), the alkyl group represented by R ¹ has 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms, more preferably 1 to 5 carbon atoms. . The alkyl group may be linear or branched.

In general formula (A), the phenyl group represented by R ¹ has 6 to 10 carbon atoms, and more preferably 6 to 8 carbon atoms. Examples of the substituent substituted with the phenyl group include a methyl group, an ethyl group, and a propyl group.

In general formula (A), the alicyclic hydrocarbon group representing R ¹ has 4 to 10 carbon atoms, and more preferably 5 to 8 carbon atoms. Examples of the substituent substituted with the alicyclic hydrocarbon group include a methyl group, an ethyl group, and a propyl group.

In the general formula (A), in “—CH ₂ —O—R ⁶ ” representing R ^{2 to} R ⁵ , the alkyl group representing R ⁶ has 1 to 10 carbon atoms, and desirably has carbon atoms. 1 to 8 and more preferably 1 to 6 carbon atoms. The alkyl group may be linear or branched. Desirably, a methyl group, an ethyl group, a butyl group, etc. are mentioned.

As the compound represented by the general formula (A), it is particularly desirable that R ¹ represents a substituted or unsubstituted phenyl group having 6 to 10 carbon atoms, and R ^{2 to} R ⁵ are each independently —CH ₂ —O. it is a compound represented by -R ^6. R ⁶ is preferably selected from a methyl group and an n-butyl group.

  The compound represented by the general formula (A) is synthesized by a known method using, for example, guanamine and formaldehyde (for example, see Experimental Chemistry Course 4th edition, Vol. 28, page 430).

  Specific examples of the compound represented by the general formula (A) are shown below, but are not limited thereto. Moreover, although the following specific examples show the thing of a monomer, the multimer (oligomer) which uses these as a structural unit may be sufficient.

  Commercially available products of the compound represented by the general formula (A) include, for example, “Superbecamine (R) L-148-55, Superbecamine (R) 13-535, Superbecamine (R) L-145- 60, Super Becamine (R) TD-126 "or more manufactured by DIC Corporation," Nicarac BL-60, Nicarac BX-4000 "or more, Sanwa Chemical Co., Ltd., and the like.

  In addition, the compound represented by the general formula (A) (including multimers) can be used in a suitable solvent such as toluene, xylene, ethyl acetate, etc., in order to remove the influence of residual catalyst after synthesis or after purchasing a commercial product. It may be dissolved and washed with distilled water, ion exchange water or the like, or may be removed by treatment with an ion exchange resin.

  Next, the compound having a melamine structure (melamine compound) is particularly preferably at least one of a compound represented by the following general formula (B) and a multimer thereof. Here, like the general formula (A), the multimer is an oligomer polymerized using the compound represented by the general formula (B) as a structural unit, and the degree of polymerization thereof is, for example, 2 or more and 200 or less (preferably 2 or more and 100). The following). In addition, the compound shown by General formula (B) or its multimer may be used individually by 1 type, or may use 2 or more types together. Moreover, you may use together with the compound shown by the said general formula (A), or its multimer.

In general formula (B), R ^{7 to} R ¹² each independently represent a hydrogen atom, —CH ₂ —OH, —CH ₂ —O—R ¹³ , and R ¹³ is branched from 1 to 5 carbon atoms. Or a good alkyl group. Examples of R ¹³ include a methyl group, an ethyl group, and a butyl group.

  The compound represented by the general formula (B) is synthesized by, for example, a known method using melamine and formaldehyde (for example, synthesized according to the melamine resin in the 4th edition of Experimental Chemistry Course, Vol. 28, page 430). Is done.

  Specific examples of the compound represented by the general formula (B) are shown below, but are not limited thereto. Moreover, although the following specific examples show the thing of a monomer, the multimer (oligomer) which uses these as a structural unit may be sufficient.

  As a commercial item of the compound represented by the general formula (B), for example, Super Melami No. 90 (manufactured by NOF Corporation), Super Becamine (R) TD-139-60 (manufactured by DIC), Uban 2020 (Mitsui Chemicals), Sumitex Resin M-3 (Sumitomo Chemical Industries), Nicarak MW-30 (three) (Wa Chemical Co., Ltd.)).

  In addition, the compound represented by the general formula (B) (including multimers) is dissolved in an appropriate solvent such as toluene, xylene or ethyl acetate after synthesis or after purchase of a commercial product in order to remove the influence of residual catalyst. It may be washed with distilled water, ion exchange water or the like, or may be removed by treatment with ion exchange resin.

[Other ingredients]
The surface protective layer 5 may contain a fluorine-containing resin.
Fluorine-containing resins include tetrafluoroethylene resin (PTFE), trifluorinated ethylene chloride resin, hexafluoropropylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorinated dichloride ethylene resin and their co-polymers. The combination etc. are mentioned, Among these, 1 type (s) or 2 or more types are selected and used. More preferably, they are tetrafluoroethylene resin and vinylidene fluoride resin, and particularly preferably tetrafluoroethylene resin.

The average primary particle size of the fluorine-containing resin to be used is desirably 0.05 μm or more and 1 μm or less, and more desirably 0.1 μm or more and 0.5 μm or less.
The average primary particle size of the fluorine-containing resin is obtained by using a laser diffraction particle size distribution measuring apparatus LA-700 (manufactured by Horiba Seisakusho) and measuring liquid diluted in the same solvent as the dispersion liquid in which the fluorine-containing resin is dispersed. A value measured at a refractive index of 1.35.

  The content of the fluorine-containing resin is preferably 5% by mass or more and 12% by mass or less, and more preferably 7% by mass or more and 10% by mass or less with respect to the total solid content of the surface protective layer.

  For the surface protective layer 5, a thermosetting resin such as a phenol resin, a melamine resin, a urea resin, an alkyd resin, or a benzoguanamine resin may be used. In addition, a compound having a larger number of functional groups in one molecule such as a spiroacetal guanamine resin (for example, “CTU-guanamine” (Ajinomoto Fine Techno Co., Ltd.)) may be copolymerized with the material in the crosslinked product.

  Further, a surfactant may be added to the surface protective layer 5. As the surfactant to be used, a surfactant containing at least one kind of structure among a fluorine atom, an alkylene oxide structure, and a silicone structure is preferably exemplified.

  An antioxidant may be added to the surface protective layer 5. Antioxidants are preferably hindered phenols or hindered amines, organic sulfur antioxidants, phosphite antioxidants, dithiocarbamate antioxidants, thiourea antioxidants, benzimidazole antioxidants. , Etc., may be used. The addition amount of the antioxidant is preferably 20% by mass or less, and more preferably 10% by mass or less.

  Examples of the hindered phenol antioxidant include 2,6-di-t-butyl-4-methylphenol, 2,5-di-t-butylhydroquinone, N, N′-hexamethylene bis (3,5-di). -T-butyl-4-hydroxyhydrocinnamide, 3,5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, 2,4-bis [(octylthio) methyl] -o-cresol, 2,6-di-t-butyl-4-ethylphenol, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol) 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 2,5-di-t-amylhydroquinone, 2-t-butyl-6- (3-butyl-2- Dorokishi-5-methylbenzyl) -4-methylphenyl acrylate, 4,4'-butylidene bis (3-methyl -6-t-butylphenol) and the like.

  The surface protective layer 5 may contain a curing catalyst for accelerating the curing of the charge transport material, the guanamine compound and the melamine compound. An acid catalyst is preferably used as the curing catalyst. Acid-based catalysts include acetic acid, chloroacetic acid, trichloroacetic acid, trifluoroacetic acid, oxalic acid, maleic acid, malonic acid, lactic acid and other aliphatic carboxylic acids, benzoic acid, phthalic acid, terephthalic acid, trimellitic acid, etc. Aromatic carboxylic acids, methane sulfonic acids, dodecyl sulfonic acids, benzene sulfonic acids, aliphatics such as dodecyl benzene sulfonic acids, naphthalene sulfonic acids, and aromatic sulfonic acids are used, but sulfur-containing materials should be used. desirable.

  The sulfur-containing material as the curing catalyst is desirably one that exhibits acidity at room temperature (for example, 25 ° C.) or after heating, and is most desirably at least one of organic sulfonic acids and derivatives thereof. The presence of these catalysts in the surface protective layer 5 is easily confirmed by energy dispersive X-ray analysis (EDS), X-ray photoelectron spectroscopy (XPS) or the like.

  Examples of the organic sulfonic acid and / or a derivative thereof include p-toluenesulfonic acid, dinonylnaphthalenesulfonic acid (DNNSA), dinonylnaphthalenedisulfonic acid (DNNDSA), dodecylbenzenesulfonic acid, and phenolsulfonic acid. Among these, p-toluenesulfonic acid and dodecylbenzenesulfonic acid are desirable. Moreover, as long as it can dissociate in a curable resin composition, you may use an organic sulfonate.

Further, a so-called thermal latent catalyst, which has a high catalytic ability when heated, may be used.
As a heat latent catalyst, for example, a microcapsule in which an organic sulfone compound or the like is encapsulated in a polymer form, an adsorbed acid or the like on a pore compound such as zeolite, and a proton acid and / or proton acid derivative is blocked with a base Thermal latent proton acid catalyst, proton acid and / or proton acid derivative esterified with primary or secondary alcohol, proton acid and / or proton acid derivative blocked with vinyl ethers and / or vinyl thioethers , Boron trifluoride monoethylamine complex, boron trifluoride pyridine complex, and the like.

Of these, a protonic acid and / or a protonic acid derivative blocked with a base is desirable.
As the protonic acid of the heat latent protonic acid catalyst, sulfuric acid, hydrochloric acid, acetic acid, formic acid, nitric acid, phosphoric acid, sulfonic acid, monocarboxylic acid, polycarboxylic acids, propionic acid, oxalic acid, benzoic acid, acrylic acid, methacrylic acid, Itaconic acid, phthalic acid, maleic acid, benzenesulfonic acid, o, m, p-toluenesulfonic acid, styrenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, decylbenzenesulfonic acid, undecylbenzenesulfonic acid, Examples include tridecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, dodecylbenzenesulfonic acid and the like. In addition, as protonic acid derivatives, neutralized products such as alkali metal salts of alkaline acids or alkaline earth metal circles such as sulfonic acid and phosphoric acid, and polymer compounds in which a protonic acid skeleton is introduced into the polymer chain (polyvinylsulfone) Acid, etc.). Examples of the base that blocks the protonic acid include amines.

  Amines are classified as primary, secondary or tertiary amines. There is no restriction in particular and any of them may be used.

  Examples of the primary amine include methylamine, ethylamine, propylamine, isopropylamine, n-butylamine, isobutylamine, t-butylamine, hexylamine, 2-ethylhexylamine, secondary butylamine, allylamine, and methylhexylamine.

  As secondary amines, dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, diisobutylamine, di-t-butylamine, dihexylamine, di (2-ethylhexyl) amine, N-isopropyl N-isobutylamine , Di (2-ethylhexyl) amine, disecondary butylamine, diallylamine, N-methylhexylamine, 3-pipecoline, 4-pipecoline, 2,4-lupetidine, 2,6-lupetidine, 3,5-lupetidine, morpholine, N -Methylbenzylamine and the like.

  As tertiary amines, trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, triisobutylamine, tri-t-butylamine, trihexylamine, tri (2-ethylhexyl) amine, N-methylmorpholine, N, N-dimethylallylamine, N-methyldiallylamine, triallylamine, N, N-dimethylallylamine, N, N, N ′, N′-tetramethyl-1,2-diaminoethane, N, N, N ′, N '-Tetramethyl-1,3-diaminopropane, N, N, N', N'-tetraallyl-1,4-diaminobutane, N-methylpiperidine, pyridine, 4-ethylpyridine, N-propyldiallylamine, 3- Dimethylaminopropanol, 2-ethylpyrazine, 2,3-di Tilpyrazine, 2,5-dimethylpyrazine, 2,4-lutidine, 2,5-lutidine, 3,4-lutidine, 3,5-lutidine, 2,4,6-collidine, 2-methyl-4-ethylpyridine, 2-methyl-5-ethylpyridine, N, N, N ′, N′-tetramethylhexamethylenediamine, N-ethyl-3-hydroxypiperidine, 3-methyl-4-ethylpyridine, 3-ethyl-4-methyl Pyridine, 4- (5-nonyl) pyridine, imidazole, N-methylpiperazine and the like can be mentioned.

Commercially available products include “NACURE2501” (toluenesulfonic acid dissociation, methanol / isopropanol solvent, pH 6.0 to pH 7.2, dissociation temperature 80 ° C.), “NACURE2107” (p-toluenesulfonic acid dissociation, manufactured by King Industries, Inc. Isopropanol solvent, pH 8.0 to pH 9.0, dissociation temperature 90 ° C.) “NACURE 2500” (p-toluenesulfonic acid dissociation, isopropanol solvent, pH 6.0 to pH 7.0, dissociation temperature 65 ° C.), “NACURE 2530” (P-toluenesulfonic acid dissociation, methanol / isopropanol solvent, pH 5.7 to pH 6.5, dissociation temperature 65 ° C.), “NACURE2547” (p-toluenesulfonic acid dissociation, aqueous solution, pH 8.0 to pH 9.0, Dissociation temperature 107 ), “NACURE2558” (p-toluenesulfonic acid dissociation, ethylene glycol solvent, pH 3.5 to pH4.5, dissociation temperature 80 ° C.), “NACUREXP-357” (p-toluenesulfonic acid dissociation, methanol solvent, pH 2. 0 to pH 4.0, dissociation temperature 65 ° C.) “NACUREXP-386” (p-toluenesulfonic acid dissociation, aqueous solution, pH 6.1 to pH 6.4, dissociation temperature 80 ° C.), “NACUREX C-2211” (p -Toluenesulfonic acid dissociation, pH 7.2 to pH 8.5, dissociation temperature 80 ° C.), “NACURE 5225” (dodecylbenzenesulfonic acid dissociation, isopropanol solvent, pH 6.0 to pH 7.0, dissociation temperature 120 ° C.), “ NACURE 5414 "(dodecylbenzenesulfonic acid dissociation, key Ren solvent, dissociation temperature 120 ° C.), “NACURE 5528” (dodecylbenzenesulfonic acid dissociation, isopropanol solvent, pH 7.0 to pH 8.0, dissociation temperature 120 ° C.), “NACURE 5925” (dodecylbenzenesulfonic acid dissociation, pH 7.0) PH 7.5 or less, dissociation temperature 130 ° C., “NACURE 1323” (disinyl naphthalene sulfonic acid dissociation, xylene solvent, pH 6.8 to pH 7.5, dissociation temperature 150 ° C.), “NACURE 1419” (dinonyl naphthalene sulfonic acid Dissociation, xylene / methyl isobutyl ketone solvent, dissociation temperature 150 ° C.), “NACURE1557” (dinonylnaphthalenesulfonic acid dissociation, butanol / 2-butoxyethanol solvent, pH 6.5 to pH 7.5, dissociation temperature 150 ° C.), “ NA CUREX 49-110 ”(dinonyl naphthalene disulfonic acid dissociation, isobutanol / isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 90 ° C.),“ NACURE 3525 ”(dinonyl naphthalene disulfonic acid dissociation, isobutanol / isopropanol solvent, pH 7.0 to pH 8.5, dissociation temperature 120 ° C., “NACUREXP-383” (dinonyl naphthalene disulfonic acid dissociation, xylene solvent, dissociation temperature 120 ° C.), “NACURE 3327” (dinonyl naphthalene disulfonic acid dissociation, isobutanol / Isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 150 ° C.), “NACURE4167” (phosphoric acid dissociation, isopropanol / isobutanol solvent, pH 6.8 to pH 7.3, dissociation temperature 80 ), “NACUREXP-297” (phosphoric acid dissociation, water / isopropanol solvent, pH 6.5 to pH 7.5, dissociation temperature 90 ° C., “NACURE 4575” (phosphoric acid dissociation, pH 7.0 to pH 8.0, dissociation temperature) 110 ° C.).
These thermal latent catalysts may be used alone or in combination of two or more.

  Here, the blending amount of the catalyst is desirably in the range of 0.1% by mass to 10% by mass with respect to the total solid content excluding the fluorine-containing resin in the coating solution, and particularly 0.1% by mass to 5%. The mass% or less is desirable.

[Method for forming surface protective layer]
The surface protective layer 5 is prepared by preparing a coating solution for forming a surface protective layer containing each of the aforementioned components in a solvent, applying the coating solution to form a coating film, and heating the coating film. And a heating step of polymerizing at least the reactive charge transport material to form a polymer and drying to remove the solvent.

  Examples of the solvent used in the coating solution for the surface protective layer include cyclic aliphatic ketone compounds such as cyclobutanone, cyclopentanone, cyclohexanone and cycloheptanone; cyclic such as methanol, ethanol, propanol, butanol and cyclopentanol; Linear alcohols; linear ketones such as acetone and methyl ethyl ketone; cyclic or linear ethers such as tetrahydrofuran, dioxane, ethylene glycol, and diethyl ether; halogenated aliphatic carbonization such as methylene chloride, chloroform, and ethylene chloride A hydrogen solvent etc. are mentioned. A solvent may be used individually by 1 type, or may mix and use 2 or more types.

  In the heating step, for example, the charge transport material having the above-mentioned reactive functional group is polymerized by heating at a temperature of 100 ° C. or more and 170 ° C. or less for 30 minutes or more and 60 minutes or less, and further, the aforementioned guanamine compound or melamine compound is added. In such a case, the cross-linking polymerization proceeds to form a polymer, and the solvent is removed to obtain the surface protective layer 5.

(Single layer type photosensitive layer)
The single-layer type photosensitive layer (charge generation / charge transport layer) includes, for example, a binder resin, a charge generation material, and a charge transport material. Preferred examples of these materials include those described in the charge generation layer and the charge transport layer.
In the single-layer type photosensitive layer, the content of the charge generating material is preferably 10% by mass or more and 85% by mass or less, and more preferably 20% by mass or more and 50% by mass or less. In addition, the content of the charge transport material is desirably 5% by mass or more and 50% by mass or less.
As a method for forming a single layer type photosensitive layer, a method for forming a charge generation layer or a charge transport layer is applied. The thickness of the single-layer type photosensitive layer is preferably 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 40 μm or less.

(Other)
In the electrophotographic photosensitive member according to the exemplary embodiment, the photosensitive layer and the surface protective layer include a photosensitive layer for the purpose of preventing degradation of the photosensitive member due to ozone, oxidizing gas, or light / heat generated in the image forming apparatus. You may add additives, such as antioxidant, a light stabilizer, and a heat stabilizer in it.
Further, at least one kind of electron accepting substance may be added to the photosensitive layer and the surface protective layer for the purpose of improving sensitivity, reducing residual potential, and reducing fatigue during repeated use.
Further, in the photosensitive layer and the surface protective layer, silicone oil may be added as a leveling agent to the coating solution for forming each layer to suppress film thickness unevenness of the coating film.

-Charging device-
The charging device 8 is connected to a power source 9 and a voltage is applied by the power source 9 to charge the surface of the electrophotographic photosensitive member 7.
Examples of the charging device 8 include a contact-type charger using a conductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube, and the like. Examples of the charging device 8 include a non-contact type roller charger and a known charger such as a scorotron charger using a corona discharge or a corotron charger. As the charging device 8, a contact-type charger is preferable.

-Exposure device-
The exposure device 10 exposes the charged electrophotographic photosensitive member 7 to form an electrostatic latent image on the electrophotographic photosensitive member 7.
Examples of the exposure apparatus 10 include optical system devices that expose the surface of the electrophotographic photoreceptor 7 with light such as semiconductor laser light, LED light, and liquid crystal shutter light in an image-like manner. The wavelength of the light source is preferably in the spectral sensitivity region of the electrophotographic photoreceptor 7. As the wavelength of the semiconductor laser, for example, near infrared having an oscillation wavelength around 780 nm is preferable. However, the present invention is not limited to this wavelength, and a laser having an oscillation wavelength of 600 nm or a laser having an oscillation wavelength of 400 nm to 450 nm as a blue laser may be used. Further, as the exposure apparatus 10, for example, a surface emitting laser light source of a multi-beam output type is also effective for color image formation.

-Developer-
The developing device 11 has a developing roll 11A (an example of a developer holding body) that contains a developer containing toner and holds the developer on the surface, and the developer held on the surface of the developing roll 11A generates electrons. The electrostatic latent image formed on the surface of the photographic photoreceptor 7 is developed to form a toner image. In the developing device 11, for example, a developing roll 11A is disposed in a developing region so as to face the electrophotographic photosensitive member 7 in a developing region.

Hereinafter, the developer used in the developing device 11 will be described.
The developer may be a single component developer of toner alone or a two component developer containing toner and carrier.

Toner As the toner, a small diameter toner having a volume average particle size of 4.0 μm or less (desirably 2.5 μm or more and 3.8 μm or less, more desirably 3.0 μm or more and 3.5 μm or less) is applied. When the volume average particle size is in the above range, an image with excellent gradation and high resolution is formed.
The average circularity of the toner is preferably 0.900 or more and 0.998 or less, and more preferably 0.950 or more and 0.980 or less.
The volume average particle diameter and average circularity of the toner correspond to the volume average particle diameter and average circularity of the toner particles.

  Further, the average shape factor SF1 of the toner is preferably from 100 to 130, and more preferably from 110 to 130.

Here, the measuring method of the volume average particle diameter D50v of the toner (toner particles) is as follows.
First, 0.5 mg to 50 mg of a measurement sample was added to 2 ml of a 5 mass% aqueous solution of a surfactant (desirably sodium alkylbenzenesulfonate) as a dispersant, and this was added to 100 ml to 150 ml of an electrolytic solution. The electrolytic solution in which the measurement sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for 1 minute, and a particle size of 100 μm with an aperture diameter of 100 μm is used with a Coulter Multisizer II type (manufactured by Beckman-Coulter). The particle size distribution of particles in the range of 2.0 μm to 60 μm is measured. The number of particles to be measured is 50,000.
For the particle size range (channel) obtained by dividing the obtained particle size distribution, the volume cumulative distribution is subtracted from the small particle size side, and the particle size that becomes 50% cumulative is defined as the volume average particle size D50v.

  On the other hand, the average circularity of toner (toner particles) is (circumference equivalent to circle) / (perimeter) [(perimeter of circle having the same projection area as the particle image) / (perimeter of particle projection image)] A flow type particle image analyzer (for example, a particle image is captured as a still image by sucking and collecting the toner to be measured, forming a flat flow, and instantly flashing light, and analyzing the particle image (for example, It is obtained by FPIA-2100) manufactured by Sysmex Corporation. The number of samplings when obtaining the average circularity is 3500.

In addition, the shape factor SF1 is obtained by the following equation.
Formula: SF1 = 100π × (ML) ² / (4 × A)
In the above formula, ML is the maximum particle length, and A is the projected area of the particle. The maximum length and projected area of the particles are determined by observing the particles sampled on the slide glass with an optical microscope, taking them into an image analysis apparatus (LUZEX III, manufactured by NIRECO) through a video camera, and performing image analysis. In this case, the number of sampling is 100 or more, and the shape factor shown in the above equation is obtained using the average value.

-Toner composition-
The toner may be composed of toner particles alone or may be composed of toner particles and an external additive.

  The toner particles are configured to contain, for example, a binder resin, a colorant, a release agent, and other internal additives.

  The binder resin is not particularly limited, but styrenes (eg, styrene, chlorostyrene, etc.), monoolefins (eg, ethylene, propylene, butylene, isoprene, etc.), vinyl esters (eg, vinyl acetate, vinyl propionate, Vinyl benzoate, vinyl butyrate, etc.), α-methylene aliphatic monocarboxylic acid esters (eg methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, methacrylic acid) Ethyl acetate, butyl methacrylate, dodecyl methacrylate, etc.), vinyl ethers (eg, vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether), vinyl ketones (eg, vinyl methyl ketone, vinyl hexyl ketone, vinyl isopro) Homopolymers and copolymers of Niruketon etc.), etc., and polyester resins by copolymerization of dicarboxylic acids and diols.

Particularly representative binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. Examples thereof include a polymer, a polyethylene resin, a polypropylene resin, and a polyester resin.
Typical binder resins include polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like.

  Examples of the colorant include magnetic powder (eg, magnetite, ferrite, etc.), carbon black, aniline blue, caryl blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, Lamp Black, Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 is a typical example.

  Examples of mold release agents include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum waxes such as montan wax; ester types such as fatty acid esters and montanic acid esters. Wax; and the like, but is not limited thereto.

  Examples of other internal additives include magnetic materials, charge control agents, inorganic powders, and the like.

Examples of the external additive include inorganic particles. Examples of the inorganic particles include SiO ₂ , TiO ₂ , Al ₂ O ₃ , CuO, ZnO, SnO ₂ , CeO ₂ , Fe ₂ O ₃ , MgO, BaO, and CaO. , K ₂ O, Na ₂ O, ZrO ₂ , CaO.SiO ₂ , K ₂ O. (TiO ₂ ) _n , Al ₂ O ₃ .2SiO ₂ , CaCO ₃ , MgCO ₃ , BaSO ₄ , MgSO _{4 and the} like. .

  The surface of the external additive may be hydrophobized in advance. The hydrophobic treatment is performed, for example, by immersing inorganic particles in a hydrophobic treatment agent. The hydrophobizing agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents and the like. These may be used individually by 1 type and may use 2 or more types together.

-Toner production method-
For example, the toner may be mixed with an external additive after obtaining toner particles.
The method for producing the toner particles is not particularly limited by the production method. For example, kneading and pulverization in which a binder resin, other colorant, release agent, and other internal additives are added and kneaded, pulverized, and classified. Method: Method of changing the shape of particles obtained by kneading and pulverization method by mechanical impact force or thermal energy; Emulsion polymerization of polymerizable monomer of binder resin, and formed dispersion or other coloring An emulsion polymerization aggregation method in which a dispersing agent, a release agent and other internal additives are mixed, agglomerated, and heat-sealed; a polymerizable monomer for obtaining a binder resin, other colorants, a release agent Suspension polymerization method in which a solution of an agent and other internal additives is suspended in an aqueous solvent for polymerization; a binder resin, a solution of other colorants, a release agent, and other internal additives are suspended in an aqueous solvent Examples thereof include a dissolution suspension method in which granulation is performed.
The toner particles may be core-shell toner particles obtained by using the toner particles obtained by the above method as a core, and further adhering and aggregating aggregated particles.
As a method for producing the toner particles, a suspension polymerization method, an emulsion polymerization aggregation method, and a dissolution suspension method in which an aqueous solvent is used are desirable from the viewpoint of shape control and particle size distribution control, and an emulsion polymerization aggregation method is particularly desirable.

  When the toner includes an external additive, the toner is manufactured by mixing the toner particles and the external additive with a Henschel mixer or a V blender. Further, when the toner particles are produced by a wet method, they may be externally added by a wet method.

-Carrier As the carrier, for example, iron powder, glass beads, ferrite powder, nickel powder, or those having a resin coating on the surface thereof may be mentioned.
The mixing ratio (mass ratio) of the toner and the carrier is, for example, in the range of toner: carrier = 1: 100 to 30: 100.

-Transfer device-
The transfer device 12 transfers the toner image developed on the electrophotographic photoreceptor 7 onto a recording sheet.
Examples of the transfer device 12 include known transfer chargers such as a contact transfer charger using a belt, a roller, a film, a rubber blade, a scorotron transfer charger using a corona discharge, and a corotron transfer charger. Can be mentioned.

-Cleaning device-
The cleaning device 13 removes toner remaining on the electrophotographic photosensitive member 7 after transfer.
The cleaning device 13 preferably has a cleaning blade that contacts the electrophotographic photoreceptor 7 at a linear pressure of 10 g / cm to 150 g / cm. The cleaning device 13 includes, for example, a housing, a cleaning blade, and a cleaning brush disposed on the downstream side of the cleaning blade in the rotation direction of the electrophotographic photosensitive member 7. In addition, for example, a solid lubricant is disposed in contact with the cleaning brush.

-Static neutralizer-
The static eliminator 14 is a device that charges the electrophotographic photosensitive member 7 after the toner image is transferred by the transfer device 12, and then exposes and discharges the static electricity. For example, as shown in FIG. 1, it has a charging member 14A and a static elimination exposure member 14B, and at the time of charging, charging is performed with a constant current controlled current having an applied current value of 250 μA or more and 350 μA or less.
If the applied current value is less than the lower limit value, the occurrence of seizure ghost is not suppressed. On the other hand, if the upper limit is exceeded, the residual potential of the electrophotographic photosensitive member increases.

  The applied current value is preferably in the range of 270 μA to 320 μA.

The applied current value is obtained by installing an ammeter (VOAC7412, manufactured by Iwatatsu Measurement Co., Ltd.) between the charging member 14A (for example, scorotron or charging roller) in the static eliminator and the photoconductor, Measure the current flowing through the body.
The numerical values described in this specification are measured by the above method.

The charging member 14 </ b> A is connected to a power source (not shown) and charges the surface of the electrophotographic photosensitive member 7. As the charging member 14A, a non-contact charging member or a contact charging member can be used. FIG. 1 shows a charger using non-contact type corona discharge, and examples thereof include a scorotron charger and a corotron charger. Examples of the contact charging member include a contact charger using a conductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube, and the like.
The charging member 14A is preferably a non-contact type charger.

The static eliminator 14 charges the surface of the electrophotographic photosensitive member 7 by the charging member 14A, and then performs static elimination by exposing the surface of the electrophotographic photoreceptor 7 with a static elimination exposure device (erase device) 14B.
The static elimination exposure apparatus 14B irradiates, for example, static elimination light over the entire axial width direction of the electrophotographic photosensitive member 7, and the potential difference between the exposed portion and the non-exposed portion by the exposure device 10 generated on the surface of the electrophotographic photosensitive member 7. Remove.
There is no restriction | limiting in particular as a light source of the static elimination exposure apparatus 14B, For example, a tungsten lamp (for example, white light), a light emitting diode (LED: for example, red light), etc. are mentioned.

-Fixing device-
The image forming apparatus 101 includes a fixing device 15 that fixes the toner image on the recording paper P after the transfer process. The fixing device is not particularly limited, and examples thereof include known fixing devices such as a heat roller fixing device and an oven fixing device.

  Next, the operation of the image forming apparatus 101 according to the present embodiment will be described. First, the electrophotographic photoreceptor 7 rotates in the direction indicated by the arrow A, and at the same time is negatively charged by the charging device 8.

  The electrophotographic photosensitive member 7 whose surface is negatively charged by the charging device 8 is exposed by the exposure device 10 to form an electrostatic latent image on the surface.

  When the portion where the electrostatic latent image is formed on the electrophotographic photosensitive member 7 approaches the developing device 11, the developing device 11 attaches toner to the electrostatic latent image and forms a toner image.

  When the electrophotographic photosensitive member 7 on which the toner image is formed further rotates in the direction of arrow A, the toner image is transferred onto the recording paper P by the transfer device 12. As a result, a toner image is formed on the recording paper P.

  The toner image is fixed on the recording paper P on which the image is formed by the fixing device 15.

<Process cartridge>
For example, the image forming apparatus according to the present embodiment may be configured such that a process cartridge including the electrophotographic photosensitive member 7, the developing device 11, and the charge eliminating device 14 according to the present embodiment is attached to and detached from the image forming apparatus. .
The configuration of the process cartridge according to the present embodiment only needs to include at least the electrophotographic photosensitive member 7 according to the present embodiment, the developing device 11, and the charge removal device 14. In addition to these, for example, the charging device 8, At least one component selected from the exposure device 10, the transfer device 12, and the cleaning device 13 may be provided.

  In addition, the image forming apparatus according to the present embodiment is not limited to the above-described configuration. For example, the cleaning apparatus 13 is around the electrophotographic photosensitive member 7 and downstream of the transfer device 12 in the rotation direction of the electrophotographic photosensitive member 7. Alternatively, a cleaning static eliminator may be provided on the upstream side in the rotation direction of the electrophotographic photosensitive member 7 so that the polarity of the remaining toner is aligned and easily removed with a cleaning brush.

  In addition, the image forming apparatus according to the present embodiment is not limited to the above-described configuration, and a known configuration, for example, an intermediate for transferring the toner image formed on the electrophotographic photosensitive member 7 to the intermediate transfer member and then transferring the toner image to the recording paper P. A transfer type image forming apparatus may be employed, or a tandem type image forming apparatus may be employed.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example and a comparative example, this invention is not limited to a following example at all. In the following description, “parts” and “%” are based on mass unless otherwise specified.

<< Developer >>
[Comparative developer 1]
(Preparation of Comparative Toner Particle 1)
-Synthesis of crystalline polyester resin (1)-
In a heat-dried three-necked flask, 124 parts of ethylene glycol, 22.2 parts of sodium dimethyl 5-sulfoisophthalate, 213 parts of dimethyl sebacate, and 0.3 part of dibutyltin oxide as a catalyst were added, and then the vessel was subjected to a decompression operation. The inside air was brought into an inert atmosphere with nitrogen gas, and stirred at 180 ° C. for 5 hours by mechanical stirring. Thereafter, the temperature was gradually raised to 220 ° C. under reduced pressure, and the mixture was stirred for 4 hours. When it became a viscous state, it was air-cooled, the reaction was stopped, and 220 parts of crystalline polyester resin (1) was synthesized.
The molecular weight measurement (polystyrene conversion) by gel permeation chromatography revealed that the obtained crystalline polyester resin (1) had a weight average molecular weight (MW) of 19000 and a number average molecular weight (Mn) of 5800.
Further, when the melting temperature (Tm) of the crystalline polyester resin (1) was measured using a differential scanning calorimeter (DSC) by the above-described measuring method, it had a clear peak, and the peak top temperature was 70. ° C.

-Preparation of resin dispersion-
150 parts of crystalline polyester resin (1) was put in 850 parts of distilled water, and mixed and stirred with a homogenizer (IKA Japan, Ultratarax) while heating to 80 ° C. to obtain a resin particle dispersion.

-Preparation of colorant dispersion-
250 parts of carbon black, 20 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) and 700 parts of ion-exchanged water were mixed and dissolved, and then a homogenizer (manufactured by IKA: Ultra Tarax). Was used to prepare a colorant dispersion liquid in which a colorant was dispersed.

-Preparation of release agent dispersion-
In a round stainless steel flask, 100 parts of paraffin wax (HNP0190, manufactured by Nippon Seiwa Co., Ltd., melting temperature 85 ° C.), 5 parts of cationic surfactant (Sanisol B50, manufactured by Kao Corporation), and 240 parts of ion-exchanged water are added. After dispersing for 10 minutes using a homogenizer (Ultra Turrax T50, manufactured by IKA), the dispersion was performed with a pressure discharge type homogenizer to prepare a release agent dispersion in which release agent particles having an average particle size of 550 nm were dispersed. .

-Production of comparative toner particles 1-
2400 parts of resin particle dispersion, 100 parts of colorant dispersion, 63 parts of release agent dispersion, 10 parts of lauroyl peroxide, 5 parts of aluminum sulfate (manufactured by Wako Pure Chemical Industries, Ltd.), 100 parts of ion-exchanged water, round stainless steel After being accommodated in a flask and adjusted to pH 2.0, the mixture was dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then heated to 65 ° C. with stirring in an oil bath for heating. After maintaining at 65 ° C. for 2.5 hours, observation with an optical microscope confirmed that aggregated particles having an average particle diameter of 4.5 μm were formed.

The pH of this aggregated particle liquid was 2.4. Therefore, an aqueous solution obtained by diluting sodium carbonate (manufactured by Wako Pure Chemical Industries, Ltd.) to 0.5% was gently added to adjust the pH to 5.0, and then heated to 75 ° C. while continuing stirring for 3.5 hours. Retained.
Thereafter, the reaction product was filtered, washed with ion-exchanged water, and then dried using a vacuum dryer, to obtain comparative toner particles 1 of K (black) color. The melting temperature of the obtained comparative toner particles 1 was 65 ° C.
With respect to the obtained comparative toner particle 1 of K color, D50 (volume average particle diameter) was measured. As a result, D50 was 4.2 μm and average shape factor SF1 was 129.

(Preparation of Comparative Developer 1)
The obtained K-color comparative toner particles 1 are obtained by firing 0.5% hexamethyldisilazane-treated silica (average particle size 40 nm) as an external additive, and treating with metatitanic acid 50% isobutyltrimethoxysilane. The titanium compound (average particle size 30 nm) 0.7% was added (both mass ratio to the toner) and mixed for 10 minutes with a 75 L Henschel mixer, and then with a wind sieving machine Hivolter 300 (manufactured by Shin Tokyo Machinery Co., Ltd.) Sieving was performed to prepare an externally added toner.
For 100 parts of ferrite core having an average particle size of 50 μm, 0.15 parts of vinylidene fluoride and 1.35 parts of a copolymer of methyl methacrylate and trifluoroethylene (polymerization ratio 80:20) are kneaded. Coating was performed using an apparatus to prepare a carrier. The obtained carrier and the externally added toner were mixed at a ratio of 100 parts: 8 parts by a 2 liter V blender to prepare Comparative Developer 1.

[Developer 1]
In the preparation of the comparative toner particles 1 of the comparative developer 1, the holding time for 65 ° C. heating and stirring was changed to 2 hours, and the 75 ° C. heating and stirring time after pH adjustment by adding sodium carbonate aqueous solution was changed to 5 hours. , K toner particles 1 were produced, and a developer 1 was obtained.

[Developer 2]
In the preparation of the comparative toner particles 1 of the comparative developer 1, the holding time for 65 ° C. heating and stirring was changed to 2 hours, and the 75 ° C. heating and stirring time after pH adjustment by adding sodium carbonate aqueous solution was changed to 4 hours. , K toner particles 2 were produced, and a developer 2 was obtained.

[Developer 3]
In the production of comparative toner particles 1 of Comparative Developer 1, the same holds except that the holding time for 65 ° C. heating and stirring is changed to 2 hours, and the 75 ° C. heating and stirring time after pH adjustment by adding sodium carbonate aqueous solution is changed to 3.5 hours. Thus, K toner particles 3 were produced, and a developer 3 was obtained.

[Developer 4]
In preparation of comparative toner particle 1 of comparative developer 1, except that the holding time of 65 ° C. heating and stirring was changed to 1.5 hours, and the heating and stirring time of 75 ° C. after pH adjustment by adding sodium carbonate aqueous solution was changed to 3.5 hours. In the same manner, K-color toner particles 4 were produced, and a developer 4 was obtained.

[Developer 5]
In the production of comparative toner particles 1 of Comparative Developer 1, the same holds except that the holding time for 65 ° C. heating and stirring is changed to 1 hour, and the 75 ° C. heating and stirring time after pH adjustment by adding sodium carbonate aqueous solution is changed to 3.5 hours Thus, K toner particles 5 were produced, and a developer 5 was obtained.
Table 1 shows a list of characteristics of the produced developers (toners).

<< Photoconductor >>
[Preparation of Photoreceptor 1]
-Production of undercoat layer-
100 parts of zinc oxide (average particle size: 70 nm, manufactured by Teica, specific surface area value: 15 m ² / g) is stirred and mixed with 500 parts of tetrahydrofuran, and 1.25 parts of KBM603 (manufactured by Shin-Etsu Chemical Co., Ltd.) is used as a silane coupling agent. And stirred for 2 hours. Then, tetrahydrofuran was distilled off under reduced pressure and baked at 120 ° C. for 3 hours to obtain silane coupling agent surface-treated zinc oxide particles.

  60 parts of the zinc oxide particles subjected to the surface treatment, 0.6 part of the electron transport agent shown in the above exemplary compound (1-2), and blocked isocyanate as a curing agent (Sumijoule 3173, manufactured by Sumitomo Bayern Urethane Co., Ltd.) 13.5 parts and 15 parts of butyral resin (ESREC BM-1, manufactured by Sekisui Chemical Co., Ltd.) in 38 parts of methyl ethyl ketone were mixed with 25 parts of methyl ethyl ketone, and glass beads having a diameter of 1 mm were used. Then, dispersion was performed for 4 hours with a sand mill to obtain a dispersion.

  To the obtained dispersion, 0.005 part of dioctyltin dilaurate and 4.0 parts of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicone) were added as a catalyst to obtain an undercoat layer coating liquid. This coating solution was applied on an aluminum substrate having a diameter of 30 mm by a dip coating method, followed by drying and curing at 180 ° C. for 40 minutes to obtain an undercoat layer having a thickness of 25 μm.

-Fabrication of charge generation layer-
Next, as a charge generating material, it has strong diffraction peaks at Bragg angles (2θ ± 0.2 °) with respect to CuKα characteristic X-rays of at least 7.4 °, 16.6 °, 25.5 ° and 28.3 °. Mix a mixture of 15 parts of chlorogallium phthalocyanine crystal, 10 parts of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nippon Union Carbide) and 300 parts of n-butyl alcohol in a sand mill using glass beads having a diameter of 1 mm. For 4 hours to obtain a coating solution for the charge generation layer. This charge generation layer coating solution was dip coated on the undercoat layer and dried at 120 ° C. for 5 minutes to obtain a charge generation layer having a thickness of 0.2 μm.

-Preparation of charge transport layer-
Subsequently, 2 parts of N, N′-bis (3-methylphenyl) -N, N′-diphenylbenzidine, N, N′-bis (3,4-dimethylphenyl) biphenyl-4-amine 2 as charge transport materials Parts, 6 parts of bisphenol Z-type polycarbonate resin (viscosity average molecular weight: 40,000), 0.1 part of 2,6-di-t-butyl-4-methylphenol as an antioxidant, and 24 parts of tetrahydrofuran and toluene 11 parts were mixed and dissolved to obtain a coating solution for the charge transport layer. This charge transport layer coating solution was dip-coated on the charge generation layer and dried at 120 ° C. for 40 minutes to obtain a charge transport layer having a thickness of 22 μm.

-Preparation of surface protective layer-
Subsequently, 10 parts of Lubron L-2 (manufactured by Daikin Industries) as tetrafluoroethylene resin particles and a fluorinated alkyl group-containing copolymer containing a repeating unit represented by the following structural formula 2 (weight average molecular weight 50,000) , L: m = 1: 1, s = 1, n = 60) 0.3 parts of cyclopentanone was stirred and mixed to prepare a tetrafluoroethylene resin particle suspension. Next, 80 parts of the compound represented by the above chemical formula I-8, 20 parts of the compound represented by chemical formula I-21, 4 parts of benzoguanamine resin (Nicarac BL-60, manufactured by Sanwa Chemical Co., Ltd.), cyclohexane In addition to 220 parts of pentanone, dissolved and mixed, the tetrafluoroethylene resin particle suspension was added, stirred and mixed, and then a high-pressure homogenizer equipped with a through-type chamber having fine channels (Yoshida Kikai Kogyo Co., Ltd.) YSSNM-1500AR) was used, and after the dispersion treatment with the pressure increased to 700 kgf / cm ² was repeated 20 times, 1 part of dimethylpolysiloxane (Granol 450, Kyoeisha Chemical Co., Ltd.) and NACURE 5225 (manufactured by King Industry Co., Ltd.) 0 .1 part was added to prepare a coating solution for the surface protective layer. The surface-sensitive layer coating solution was applied onto the charge transport layer by a dip coating method and dried at 155 ° C. for 35 minutes to form a surface-sensitive layer having a film thickness of 6 μm.

Structural formula 2

[Photoconductors 2 to 8, Comparative photoconductors 1 to 4]
By the method described in Photoreceptor 1 except that the metal oxide, coupling agent, electron transfer agent, and charge transport material used for the surface protective layer used in the undercoat layer were changed to those shown in Table 2. Each photoconductor was prepared.

  In addition, the exemplary compounds (2-1), (2-2), and (2-3) shown as electron transporting agents in Table 2 are the compounds shown below.

<< Staticizer >>
As neutralization devices having a charging member and a neutralization exposure member, neutralization devices 1 to 4 and comparative neutralization devices 1 and 2 shown in Table 3 below were prepared.
As the charging member, a product equipped with Color 1000 Press manufactured by Fuji Xerox was used as the “non-contact” charging member, and a product equipped with Apeos Port IV manufactured by Fuji Xerox was used as the charging member. The charging member was subjected to constant current control, and a DC applied current value was applied as shown in the following table. Further, a voltage Vpp = 600 kV having a frequency of 800 Hz and constant voltage controlled together with the DC current was applied (the frequency and Vpp are fixed).
Further, a product mounted with Color 1000 Press manufactured by Fuji Xerox Co., Ltd. was used as the static elimination exposure member, and the conditions were set to a wavelength of 660 nm and a light amount of 5 mJ / m ² .

<< Examples 1-15, Comparative Examples 1-17 >>
The combinations of the photoconductor, developer and static eliminator were mounted on “Apeos Port-III C4400” manufactured by Fuji Xerox Co., Ltd. as shown in Table 4 and Table 5 below, and the following evaluations were performed. The results are shown in Tables 4 and 5.

[Initial tone evaluation]
Prints (outputs) the image pattern shown in Fig. 4 in a high-temperature and high-humidity environment (30 ° C and 85%), and evaluates the gradation of the target image density of 0% to 20% and 80% to 100%. did. The process speed at this time was 320 mm / s.
The evaluation criteria are as follows.
A: The difference between the target image density and the printed actual image density is 3% or less B: The difference between the target image density and the printed actual image density is greater than 3% and 5% or less C: The target image density is printed The actual image density difference is greater than 5%. Note that the image density was measured using X-Rite 404 manufactured by X-Rite.

[Gradation evaluation after printing]
In a high-temperature and high-humidity environment (30 ° C. and 85%), 50,000 sheets of full-surface halftone image A4 paper with an image density of 5% were printed.
Thereafter, the image pattern shown in FIG. 4 was printed (output), and the gradation of the target image density of 0% to 20% and 80% to 100% was evaluated. The process speed at this time was 320 mm / s.
The evaluation criteria are as follows.
A: The difference between the target image density and the printed actual image density is 3% or less B: The difference between the target image density and the printed actual image density is greater than 3% and 5% or less C: The target image density is printed The actual image density difference is greater than 5%. Note that the image density was measured using X-Rite 404 manufactured by X-Rite.

[Initial character resolution evaluation]
The character resolution evaluation was performed by printing a 7-point character “Hibiki” and visually observing the resolution.
The evaluation criteria are as follows.
A: No character collapse.
B: Some characters are crushed.
C: The resolution is clearly poor.

[Character resolution evaluation after printing]
In a high-temperature and high-humidity environment (30 ° C. and 85%), 50,000 sheets of full-surface halftone image A4 paper with an image density of 5% were printed.
Thereafter, the character resolution evaluation was performed by printing a 7-point character “Hibi” and visually observing the resolution.
The evaluation criteria are as follows.
A: No character collapse.
B: Some characters are crushed.
C: The resolution is clearly poor.

[Scoring ghost evaluation]
In a high-temperature and high-humidity environment (30 ° C. and 85%), an image with an image density of 100% shown in FIG. 5 was printed on 1000 sheets of A3 paper. Thereafter, an entire halftone image having an image density of 20% was printed on A3 paper and evaluated.
The evaluation criteria are as follows.
A: No ghost.
B: There is some ghost.
C: Clearly ghosted.

[Measurement of residual potential]
The potential before and after the image formation test was performed by the following method was measured by the following method, and the residual potential was measured.
The image formation test method uses Apeos Port-III C4400 manufactured by Fuji Xerox Co., Ltd., and an image with an image density of 100% is printed on A3 paper (C2 paper manufactured by Fuji Xerox Co., Ltd.) in a high temperature and high humidity environment (30% 85% RH). ) 1000 sheets were printed. Before and after the image formation test, a surface potential meter probe was installed immediately before the charger of the electrophotographic photosensitive member, and the surface potential was measured with a surface potential meter (Model 334, manufactured by TREK).

DESCRIPTION OF SYMBOLS 1 Conductive base material, 2 Undercoat layer, 3 Photosensitive layer, 5 Surface protective layer, 7 Electrophotographic photoreceptor, 8 Charging apparatus, 9 Power supply, 10 Exposure apparatus, 11 Developing apparatus, 12 Transfer apparatus, 13 Cleaning apparatus, 14 Static elimination device, 14A charging member, 14B static elimination exposure member, 15 fixing device, 31 charge generation layer, 32 charge transport layer, 101 image forming apparatus, P recording paper (an example of a recording medium)

Claims (4)

A conductive substrate, an undercoat layer containing a metal oxide and an anthraquinone derivative coordinated to the metal oxide, a photosensitive layer, and a surface protective layer containing a polymer obtained by polymerizing a reactive charge transport material; And an electrophotographic photosensitive member comprising in this order,
A charging device for charging the surface of the electrophotographic photosensitive member;
An exposure device that exposes a surface of the charged electrophotographic photosensitive member to form an electrostatic latent image; and
A developer holding body that contains a developer containing a toner having a volume average particle size of 4.0 μm or less and that holds the developer on the surface, and the developer held on the surface of the developer holding body, A developing device that develops an electrostatic latent image formed on the surface of the electrophotographic photosensitive member to form a toner image;
A transfer device for transferring a toner image formed on the surface of the electrophotographic photosensitive member to a recording medium;
A static eliminator that charges the electrophotographic photosensitive member after the toner image is transferred by the transfer device at a constant current controlled current of 250 μA or more and 350 μA or less, and then exposes and eliminates the static electricity;
An image forming apparatus comprising: The image forming apparatus according to claim 1, wherein the anthraquinone derivative has a structure represented by the following general formula (1).


(In general formula (1), n1 and n2 each independently represent an integer of 0 or more and 3 or less, provided that at least one of n1 and n2 represents an integer of 1 or more and 3 or less (that is, n1 and n2 are M1 and m2 each independently represent an integer of 0 or 1. R ¹ and R ² each independently represents an alkyl group having 1 to 10 carbon atoms, or 1 to 10 carbon atoms. Represents the following alkoxy group.) A conductive substrate, an undercoat layer containing a metal oxide and an anthraquinone derivative coordinated to the metal oxide, a photosensitive layer, and a surface protective layer containing a polymer obtained by polymerizing a reactive charge transport material; And an electrophotographic photosensitive member comprising in this order,
A developer holding body that contains a developer containing a toner having a volume average particle size of 4.0 μm or less and that holds the developer on the surface is formed, and an electrostatic latent image is formed on the surface of the electrophotographic photosensitive member. A developing device for developing the electrostatic latent image with the developer held on the surface of the developer holder to form a toner image;
A charge eliminating device that charges the electrophotographic photosensitive member after transferring the toner image to a recording medium with a constant current controlled current of 250 μA or more and 350 μA or less, and then exposes and removes the charge.
A process cartridge attached to and detached from the image forming apparatus. The process cartridge according to claim 3, wherein the anthraquinone derivative has a structure represented by the following general formula (1).


(In general formula (1), n1 and n2 each independently represent an integer of 0 or more and 3 or less, provided that at least one of n1 and n2 represents an integer of 1 or more and 3 or less (that is, n1 and n2 are M1 and m2 each independently represent an integer of 0 or 1. R ¹ and R ² each independently represents an alkyl group having 1 to 10 carbon atoms, or 1 to 10 carbon atoms. Represents the following alkoxy group.)