JP2013092760A - Electrophotographic photoreceptor, electrophotographic photoreceptor cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoreceptor satisfying demands for a low residual potential, high responsiveness, wear resistance and filming resistance, and solving a problem of noise in a machine in an electrophotographic process, when a charge transporting substance and a binder resin currently used are used in the electrophotographic process.SOLUTION: The electrophotographic photoreceptor includes a photosensitive layer on a conductive support, wherein the photosensitive layer contains a plurality of types of charge transporting substances. A first charge transporting substance satisfies an expression of E_homo>-4.67 (eV)αcal>70 (Å); and a second charge transporting substance satisfies an expression of -5.0<E_homo<-4.67 (eV). The photosensitive layer has a universal hardness of 190 N/mmor more under the measurement conditions of 5 mN maximum denting load for 10 sec loading time and 10 sec unloading time in an environment at 25°C and 50% relative humidity by using a Vickers indenter, and shows an elastic deformation rate of 45 or more.

Description

  The present invention relates to an electrophotographic photosensitive member, an electrophotographic photosensitive member cartridge, and an image forming apparatus. In particular, the present invention relates to an electrophotographic photosensitive member, an electrophotographic photosensitive member cartridge, and an image forming apparatus that are excellent in wear resistance, cleaning property, and sound generation, and have excellent response and electrical characteristics.

  The electrophotographic technique is widely used in the fields of copiers, various printers, printing presses and the like because of its excellent immediacy and high quality images. As an electrophotographic photosensitive member that is the core of the electrophotographic technology, an electrophotographic photosensitive member using an organic photoconductive material having advantages such as non-pollution, easy film formation, and easy manufacture (hereinafter simply referred to as “ Also referred to as “photoreceptor”).

  As an electrophotographic photoreceptor using an organic photoconductive material, a so-called dispersion type single-layer photoreceptor in which a photoconductive fine powder is dispersed in a binder resin, a charge generation layer and a charge transport layer are laminated. Multilayer photoreceptors are known. Multilayer photoconductors provide highly efficient charge generating materials and wide and highly safe photoconductors. Also, photoconductors can be easily formed by coating, have high productivity, and are advantageous in terms of cost. This is the mainstream of photoconductors for the reasons described above, and has been developed and put into practical use.

  On the other hand, single-layer photoconductors are slightly inferior to multilayer photoconductors in terms of electrical characteristics and have a somewhat lower degree of freedom in material selection, but can generate charges near the surface of the photoconductor. Further, since the image is not blurred even if the film is thick, there is an advantage that high printing durability can be achieved by increasing the film thickness. In addition, the single-layer type photosensitive member requires fewer coating steps, is advantageous for interference fringes and tube defects derived from a conductive substrate (support), and can use an inexpensive substrate such as a non-cutting tube. For this reason, there is an advantage that the cost can be reduced.

  An electrophotographic photosensitive member using an organic photoconductive material has the above-mentioned advantages, but does not satisfy all the characteristics required for an electrophotographic photosensitive member, and in particular, it is repeatedly used in a copying machine or a printer. However, there is a problem that the photosensitive layer gradually deteriorates. Therefore, it is desired that the damage due to repeated use is small, the sensitivity is high, the residual potential is low, and the electrical characteristics are stable. These characteristics greatly depend on the charge generation material, the charge transport material, the additive, and the binder resin. As the charge generation material, a phthalocyanine pigment or an azo pigment is mainly used because it needs to have sensitivity to a light source for light input. Various types of charge transport materials are known, but amine compounds are widely used because they exhibit a very low residual potential (see, for example, Patent Document 1 and Patent Document 2). Various additives are known, but those having the effect of increasing ozone resistance are well known (for example, see Patent Document 3 and Patent Document 4). Also, as the binder resin used in the photosensitive layer, particularly the charge transport layer, a polycarbonate resin or a polyarylate resin is preferably used (see, for example, Patent Document 5).

Japanese Patent Laid-Open No. 2000-075517 JP 2002-040688 A Japanese Patent No. 2644278 Japanese Patent Laid-Open No. 9-265194 JP 2011-170041 A

However, according to the study by the present inventors, when a currently used charge transport material and binder resin are used in the electrophotographic process, low residual potential, high response, wear resistance, filming resistance and electron It is difficult to satisfy all the problems of rubbing noise (hereinafter also referred to as “sounding noise”) in the machine in the photographic process.
In order to achieve high responsiveness, the charge transport layer should contain a large amount of charge transport material, but on the other hand, the binder content will decrease and the properties of the binder will be impaired, resulting in wear resistance and scratch resistance. Etc. decreases. By using polyarylate as the binder resin, the wear resistance is improved, and the polyarylate resin also has a high elastic deformation rate, which is effective for cleaning properties and filming. However, in general, when a polyarylate resin is used, electrical characteristics are deteriorated as compared with the case where a polycarbonate resin is used. When using a polyarylate resin as a binder resin, it is particularly effective for electrical characteristics to use a charge transport material having a low ionization potential, that is, a relatively high HOMO energy level. Furthermore, if a charge transport material having a large polarizability and a large π-electron conjugation is used, a high responsiveness can be realized with a relatively low content, and the advantage of using the polyarylate resin described above That is, it can be suppressed that the wear resistance, the cleaning property and the filming resistance are impaired. However, in this case, since the content of the charge transport material is small, the surface hardness of the photoreceptor is lowered, and noise is likely to occur during printing. There is a method for solving these problems by using an additive to increase the surface hardness and keep the elastic deformation rate high without adversely affecting the electrical characteristics (see, for example, Patent Document 5). There is a disadvantage that the adhesiveness of the photosensitive layer is deteriorated.

The inventors have realized a low residual potential and high responsiveness by using a specific charge transport material, and at the same time, by controlling the surface hardness and elastic deformation rate of the photoconductor to predetermined values, It has been found that the adhesion and the filming resistance can be improved, the noise can be suppressed, and the shrinkage of the charge transport layer can be suppressed to improve the adhesion. That is, the gist of the present invention resides in the following seven points.
(1) In an electrophotographic photosensitive member having a photosensitive layer on a conductive support, the photosensitive layer includes a plurality of types of charge transport materials, and the density functional calculation of the first charge transport material B3LYP / 6-31G The energy level E_homo of HOMO obtained as a result of the structural optimization calculation by (d, p) is
E_homo> -4.67 (eV)
And the restricted Hartree-Fock method calculation in the stable structure obtained after the structure optimization calculation by the B3LYP / 6-31G (d, p) of the first charge transport material (the basis function is 6-31G ( The calculated value αcal of the polarizability α according to d, p)) is given by the following equation αcal> 70 (Å ³ )
And the energy level E_homo of HOMO obtained as a result of the structural optimization calculation by density functional calculation B3LYP / 6-31G (d, p) of the second charge transport material is
-5.0 <E_homo <-4.67 (eV)
At the maximum indentation depth when measured under the conditions of a maximum indentation load of 5 mN, load duration of 10 s, and unloading duration of 10 s using a Vickers indenter in an environment of 25 ° C and 50% relative humidity. An electrophotographic photosensitive member having a universal hardness of 190 N / mm ² or more and an elastic deformation rate of 45 or more (claim 1).

(2) The electrophotographic photosensitive member according to (1), wherein the content of the first charge transport material is 100 parts by mass or less with respect to 100 parts by mass of the binder resin. 2).
(3) The Mw of the second charge transport material is 500 or less, and the second charge transport material is contained in an amount of 50 parts by mass or less with respect to 100 parts by mass of the binder resin (1) or The electrophotographic photosensitive member according to (2) (claim 3).

(4) The electrophotographic photosensitive member according to any one of (1) to (3), wherein the photosensitive layer contains a polyarylate resin represented by the following general formula [1].

(In the formula [1], Ar ^{1 to} Ar ⁴ each independently represents an arylene group which may have a substituent, and X represents a single bond, an oxygen atom, a sulfur atom, or the following formula [2]. group, or a group represented by the following formula [3], R1 and R2 in the formula [2] are independently a hydrogen atom, an alkyl group, or aryl group, R ¹ and R ² May be bonded to form a ring, and R ³ in the formula [3] is an alkylene group, an arylene group, or a group represented by the following formula [4], and in the formula [4] R ⁴ and R ⁵ each independently represents an alkylene group, Ar ⁵ represents an arylene group, k represents an integer of 0 to 5, provided that when k = 0, any one of Ar ³ and Ar ⁴ One of them is an arylene group having a substituent.)

(In Formula [1], Y is a single bond, an oxygen atom, a sulfur atom, or a group represented by the following Formula [5]. In Formula [5], R ⁶ and R ⁷ are each independently (Represents a hydrogen atom, an alkyl group, an alkoxy group, or an aryl group, and R ⁶ and R ⁷ may combine to form a ring.)

(5) The electrophotographic photosensitive member according to any one of (1) to (4), wherein the second charge transport material is a compound represented by the following general formula [6] or general formula [7] Claim 5).

(In the general formula [6], Ar ⁶ and Ar ⁷ are aryl groups which may have a substituent having 10 or less carbon atoms constituting the aromatic ring, R represents a substituent other than hydrogen, and n represents 0 during to 7 of an integer. general formula [7], R ^9, R ¹⁰ and R ¹¹ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, or an aryl group, and the R ¹⁰ and R ¹¹ It may be bonded to form a ring.)
(6) The electrophotographic photosensitive member according to (1) to (5), a charging unit that charges the electrophotographic photosensitive member, an exposure unit that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image, An electrophotographic photosensitive member cartridge comprising: a developing unit that develops an electrostatic latent image formed on the electrophotographic photosensitive member; and at least one of a cleaning unit that cleans the electrophotographic photosensitive member. Claim 6).

  (7) The electrophotographic photosensitive member according to (1) to (5), a charging unit that charges the electrophotographic photosensitive member, an exposure unit that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image, And an image forming apparatus comprising: a developing unit that develops the electrostatic latent image formed on the electrophotographic photosensitive member.

  The electrophotographic photosensitive member of the present invention uses a plurality of specific charge transport materials to achieve low residual potential and high responsiveness while simultaneously controlling the surface hardness and elastic deformation rate of the photosensitive member to predetermined values. An electrophotographic process cartridge provided with the electrophotographic photosensitive member, which improves wear resistance and filming resistance, suppresses noise and improves adhesiveness, and the electrophotographic photosensitive member It is possible to provide an image forming apparatus including the above.

1 is a schematic diagram illustrating a main configuration of an embodiment of an image forming apparatus of the present invention. It is an indentation depth-load curve.

Hereinafter, the embodiments of the present invention will be described in detail. However, the present invention is not limited to the following descriptions, and can be appropriately modified and implemented without departing from the gist of the present invention.
[Electrophotographic photoreceptor]
Hereinafter, the electrophotographic photoreceptor of the present invention will be described in detail.

<Conductive support>
As the conductive support used for the photoreceptor, for example, metal materials such as aluminum, aluminum alloy, stainless steel, copper, and nickel, and conductive powders such as metal, carbon, and tin oxide are added to impart conductivity. A resin material, a resin, glass, paper, or the like on which a conductive material such as aluminum, nickel, or ITO (indium tin oxide) is deposited or applied on the surface is mainly used. As a form, a drum shape, a sheet shape, a belt shape or the like is used. For conductive support of metallic materials, for control of conductivity and surface properties, and for defect coating. A conductive material having an appropriate resistance value may be applied.

When a metal material such as an aluminum alloy is used as the conductive support, it may be used after an anodized film is applied. When an anodized film is applied, it is desirable to perform a sealing treatment by a known method.
For example, it is formed by anodizing in an acidic bath of chromic acid, sulfuric acid, oxalic acid, boric acid, sulfamic acid, etc., but anodizing in sulfuric acid gives better results. In the case of anodic oxidation in sulfuric acid, the sulfuric acid concentration is 100-300 g / l, the dissolved aluminum concentration is 2-15 g / l, the liquid temperature is 15-30 ° C., the electrolysis voltage is 10-20 V, and the current density is 0.5-. it is preferably in the range of 2A / dm ^2, but not limited to the above conditions.

It is preferable to perform a sealing treatment on the anodic oxide film thus formed. Sealing treatment may be performed by a normal method, for example, low-temperature sealing treatment in which it is immersed in an aqueous solution containing nickel fluoride as a main component, or high-temperature sealing in which it is immersed in an aqueous solution containing nickel acetate as a main component. It is preferable that the treatment is performed.
The concentration of the nickel fluoride aqueous solution used in the case of the low-temperature sealing treatment can be appropriately selected, but more preferable results are obtained when it is used in the range of 3-6 g / l. Further, in order to proceed the sealing treatment smoothly, the treatment temperature is 25-40 ° C., preferably 30-35 ° C., and the pH of the nickel fluoride aqueous solution is 4.5-6.5, preferably It is better to process in the range of 5.5-6.0. As the pH adjuster, oxalic acid, boric acid, formic acid, acetic acid, sodium hydroxide, sodium acetate, aqueous ammonia and the like can be used. The treatment time is preferably in the range of 1 to 3 minutes per 1 μm of film thickness. In order to further improve the physical properties of the film, cobalt fluoride, cobalt acetate, nickel sulfate, a surfactant or the like may be added to the nickel fluoride aqueous solution. Subsequently, it is washed with water and dried to finish the low temperature sealing treatment.

  As the sealing agent in the case of the high temperature sealing treatment, an aqueous solution of a metal salt such as nickel acetate, cobalt acetate, lead acetate, nickel acetate-cobalt, barium nitrate can be used, and it is particularly preferable to use nickel acetate. . The concentration in the case of using an aqueous nickel acetate solution is preferably in the range of 5-20 g / l. The treatment temperature is 80-100 ° C., preferably 90-98 ° C., and the pH of the nickel acetate aqueous solution is preferably 5.0-6.0. Here, ammonia water, sodium acetate, or the like can be used as the pH adjuster. The treatment time is 10 minutes or longer, preferably 20 minutes or longer. In this case as well, sodium acetate, organic carboxylic acid, anionic and nonionic surfactants may be added to the nickel acetate aqueous solution in order to improve the film properties.

  Subsequently, it is washed with water and dried to finish the high temperature sealing treatment. When the average film thickness is thick, stronger sealing conditions are required due to the higher concentration of the sealing liquid and high temperature / long-time treatment. Accordingly, productivity is deteriorated and surface defects such as spots, dirt, and dusting are likely to occur on the coating surface. From such a point, it is preferable that the average film thickness of the anodic oxide coating is usually 20 μm or less, particularly 7 μm or less.

The support surface may be smooth, or may be roughened by using a special cutting method or polishing. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the support. In order to reduce the cost, it is possible to use the drawing tube as it is without cutting. Especially when using non-cutting aluminum substrate such as drawing, impact processing, ironing, etc.
This is preferable because the surface is free from dirt, foreign matter, and other fouling, small scratches and the like, and a uniform and clean substrate can be obtained.

<Underlayer>
An undercoat layer may be provided between the conductive support and the photosensitive layer described later for improving adhesion and blocking properties. As the undercoat layer, a resin, a resin in which particles such as a metal oxide are dispersed, or the like is used.
Examples of the metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium titanate and barium titanate. Only one type of particles may be used, or a plurality of types of particles may be mixed and used. Among these metal particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicone. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. Moreover, the thing of a several crystal state may contain.

Various particle diameters of the metal oxide particles can be used. Among these, from the viewpoint of characteristics and liquid stability, the average primary particle diameter is preferably 10 nm or more and 100 nm or less, and particularly preferably 10 nm. It is 50 nm or less. This average primary particle size can be obtained from a TEM photograph or the like.
The undercoat layer is preferably formed in a form in which the metal oxide particles are dispersed in a binder resin. The binder resin used for the undercoat layer is epoxy resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, polyurethane resin, polyimide resin, chloride resin. Vinylidene resin, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol resin, polyurethane resin, polyacrylic acid resin, polyacrylamide resin, polyvinyl pyrrolidone resin, polyvinyl pyridine resin, water-soluble polyester resin, cellulose such as nitrocellulose Ester resin, cellulose ether resin, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, zirconium chelate compound, zirconi Organic zirconium compounds of the arm alkoxide compounds, titanyl chelate compounds, organic titanyl compounds such as titanyl alkoxide compound, may be a known binder resin such as a silane coupling agent. These can be used alone or in a cured form together with a curing agent. Among these, alcohol-soluble copolymerized polyamide, modified polyamide, and the like are preferable because they exhibit good dispersibility and coatability.

The addition ratio of the inorganic particles to the binder resin used in the undercoat layer can be arbitrarily selected. It is preferable to use in the range of 500 mass% or less.
The thickness of the undercoat layer is arbitrary as long as the effects of the present invention are not significantly impaired. Therefore, it is usually 0.01 μm or more, preferably 0.1 μm or more, and usually 30 μm or less, preferably 20 μm or less. A known antioxidant or the like may be mixed in the undercoat layer. The undercoat layer may contain pigment particles, resin particles and the like for the purpose of preventing image defects.

<Photosensitive layer>
The photosensitive layer is formed on the above-mentioned conductive support (or on the undercoat layer when the above-described undercoat layer is provided). The photosensitive layer is a layer containing a charge transport material specified in the present application. As a type of the photosensitive layer, the charge generation material and the charge transport material (including the charge transport material specified in the present application) exist in the same layer. Having a single layer structure dispersed in a binder resin (hereinafter referred to as “single layer type photosensitive layer” as appropriate), a charge generation layer in which a charge generation material is dispersed in a binder resin, and a charge transport material (specified in this application). A functionally separated layered structure composed of two or more layers, including a charge transporting layer dispersed in a binder resin (hereinafter referred to as “laminated photosensitive layer” as appropriate). However, any form may be used.

In addition, as the laminated photosensitive layer, a charge-generating layer and a charge transport layer are laminated in this order from the conductive support side, and conversely, a charge transport layer and a charge generation layer are formed from the conductive support side. There are reverse laminated photosensitive layers provided in order, and any of them can be adopted, but a forward laminated photosensitive layer that can exhibit the most balanced photoconductivity is preferable.
<Functional separation type photosensitive layer>
<Charge generation layer>
The charge generation layer of the laminated photosensitive layer (function-separated type photosensitive layer) contains a charge generation material and usually contains a binder resin and other components used as necessary. Such a charge generation layer is prepared by, for example, preparing a coating solution by dissolving or dispersing fine particles of a charge generation material and a binder resin in a solvent or a dispersion medium. It can be obtained by coating and drying on the top (on the undercoat layer when an undercoat layer is provided) and on the charge transport layer in the case of a reverse laminated type photosensitive layer.

<Charge generating material>
The charge generating material may be used alone or in a mixed state with several dyes and pigments.
Examples of the charge generating material include inorganic photoconductive materials such as selenium and its alloys, cadmium sulfide, and organic photoconductive materials such as organic pigments. Organic photoconductive materials are preferred, and organic photoconductive materials are particularly preferable. Pigments are preferred. Examples of organic pigments include phthalocyanine pigments, azo pigments, dithioketopyrrolopyrrole pigments, squalene (squarylium) pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, and benzimidazole pigments. . Among these, phthalocyanine pigments or azo pigments are particularly preferable as dyes used in the mixed state from the viewpoint of photosensitivity. When organic pigments are used as the charge generating substance, usually, fine particles of these organic pigments are used in the form of a dispersion layer bound with various binder resins.

  When a phthalocyanine pigment is used as the charge generation material, specifically, metal-free phthalocyanine and metal-containing phthalocyanine are used. Specific examples of metal-containing phthalocyanines include metals such as copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, or their oxides, halides, hydroxides, alkoxides, and the like. Various crystal forms of phthalocyanines are used. In particular, titanyl phthalocyanines (also known as oxytitanium phthalocyanine) such as A type (also known as β type), B type (also known as α type), D type (also known as Y type), vanadyl phthalocyanine, chloroindium phthalocyanine, which are highly sensitive crystal types Chlorogallium phthalocyanine such as type II, hydroxygallium phthalocyanine such as type V, μ-oxo-gallium phthalocyanine dimer such as type G and I, and μ-oxo-aluminum phthalocyanine dimer such as type II are suitable. is there.

  Among these phthalocyanines, A type (β type), B type (α type), D type (Y type) oxytitanium phthalocyanine, II type chlorogallium phthalocyanine, V type hydroxygallium phthalocyanine, G type μ-oxo- Gallium phthalocyanine dimer and the like are particularly preferable. In particular, oxytitanium phthalocyanine preferably has a clear diffraction peak mainly at a Bragg angle (2θ ± 0.2 °) of 27.2 ° in a powder X-ray diffraction spectrum by CuKα characteristic X-ray.

  Further, the oxytitanium phthalocyanine preferably has a clear diffraction peak at a Bragg angle (2θ ± 0.2 °) of 9.0 ° to 9.7 ° in a powder X-ray diffraction spectrum by CuKα characteristic X-ray. In view of the characteristics of the electrophotographic photosensitive member, main diffraction peaks at 9.6 °, 24.1 °, 27.2 °, or 9.5 °, 9.7 °, 24.1 °, and 27.2 ° are obtained. From the viewpoint of stability at the time of dispersion, it preferably has no peak at around 26.2 °. Among the oxytitanium phthalocyanines mentioned above, 7.3 °, 9.6 °, 11.6 °, 14.2 °, 18.0 °, 24.1 ° and 27.2 °, or 7.3 °, More preferably, it has main diffraction peaks at 9.5 °, 9.7 °, 11.6 °, 14.2 °, 18.0 °, 24.2 ° and 27.2 °.

  When a metal-free phthalocyanine compound or a metal-containing phthalocyanine compound is used as the charge generation material, a highly sensitive photoreceptor can be obtained with respect to a laser beam having a relatively long wavelength, for example, a laser beam having a wavelength around 780 nm. Further, when an azo pigment such as monoazo, diazo, or trisazo is used, white light, laser light having a wavelength around 660 nm, or laser light having a relatively short wavelength (for example, a wavelength in the range of 380 nm to 500 nm). It is possible to obtain a photoreceptor having sufficient sensitivity to the laser beam).

  The phthalocyanine compound may be a single compound or several mixed or mixed crystal states. As the mixed state in the phthalocyanine compound or crystal state here, those obtained by mixing the respective constituent elements later may be used, or the mixed state in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, crystallization, etc. It may be the one that gave rise to. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known. In order to generate a mixed crystal state, as described in JP-A-10-48859, two types of crystals are mixed, mechanically ground and made amorphous, and then converted into a specific crystal state by solvent treatment. The method of doing is mentioned.

  On the other hand, when an azo pigment is used as a charge generation material, various known azo pigments can be used as long as they have sensitivity to a light source for light input. Trisazo pigments are preferably used. Examples of preferred azo pigments are shown below.

  When the organic pigments exemplified above are used as the charge generation material, one kind may be used alone, or two or more kinds of pigments may be mixed and used. In this case, it is preferable to use a combination of two or more kinds of charge generating materials having spectral sensitivity characteristics in different spectral regions of the visible region and the near red region. Among them, a disazo pigment, a trisazo pigment and a phthalocyanine pigment are preferably used in combination. More preferred.

Examples of the binder resin used for the charge generation layer in the function-separated photoreceptor include polyvinyl butyral resin, polyvinyl formal resin, partially acetalized polyvinyl butyral resin in which a part of butyral is modified with formal, acetal, etc. Polyvinyl acetal resin, polyarylate resin, polycarbonate resin, polyester resin, modified ether polyester resin, phenoxy resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, polystyrene resin, acrylic resin, methacrylic resin, polyacrylamide Resin, polyamide resin, polyvinyl pyridine resin, cellulose resin, polyurethane resin, epoxy resin, silicone resin, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, casein, chloride Vinyl chloride-vinyl acetate, such as nyl-vinyl acetate copolymer, hydroxy-modified vinyl chloride-vinyl acetate copolymer, carboxyl-modified vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer Copolymer, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, styrene-alkyd resin, silicon-alkyd resin, phenol-formaldehyde resin and other insulating resins, poly-N-vinylcarbazole, polyvinylanthracene, It can be selected from organic photoconductive polymers such as polyvinyl perylene, but is not limited to these polymers. These binder resins may be used alone or in combination of two or more.

Specifically, the charge generation layer in the function-separated type photoconductor is prepared by dispersing the charge generation material by dispersing the above-mentioned binder resin in an organic solvent, and adjusting the coating solution on the conductive support (with an undercoat layer). If provided, it is formed by coating (on the undercoat layer).
Solvents used for the preparation of coating solutions and dispersion media for dissolving the binder resin include, for example, saturated aliphatic solvents such as pentane, hexane, octane and nonane, aromatic solvents such as toluene, xylene and anisole, chlorobenzene, Halogenated aromatic solvents such as dichlorobenzene and chloronaphthalene, amide solvents such as dimethylformamide and N-methyl-2-pyrrolidone, alcohol solvents such as methanol, ethanol, isopropanol, n-butanol and benzyl alcohol, glycerin, Aliphatic polyhydric alcohols such as polyethylene glycol, chain solvents such as acetone, cyclohexanone, methyl ethyl ketone, and cyclic ketone solvents, ester solvents such as methyl formate, ethyl acetate, n-butyl acetate, methylene chloride, chloroform, 1, 2-Dichro Halogenated hydrocarbon solvents such as ethane, linear ether solvents such as diethyl ether, dimethoxyethane, tetrahydrofuran, 1,4-dioxane, methylcellosolve, ethylcellosolve, acetonitrile, dimethylsulfoxide, sulfolane, hexa Examples include aprotic polar solvents such as methylphosphoric triamide, n-butylamine, isopropanolamine, diethylamine, triethanolamine, nitrogen-containing compounds such as ethylenediamine, triethylenediamine, and triethylamine, mineral oil such as ligroin, water, etc. Those which do not dissolve the undercoat layer are preferably used. These can be used alone or in combination of two or more.

  In the charge generation layer of the function-separated type photoreceptor, the compounding ratio (mass) of the binder resin and the charge generation material is 10 to 1000 parts by weight, preferably 30 to 500 parts by weight with respect to 100 parts by weight of the binder resin. The film thickness is usually 0.1 μm to 10 μm, preferably 0.15 μm to 0.6 μm. If the ratio of the charge generation material is too high, the stability of the coating solution may be reduced due to aggregation of the charge generation material. On the other hand, if the ratio of the charge generating substance is too low, the sensitivity as a photoreceptor may be reduced.

As a method for dispersing the charge generation material, a known dispersion method such as a ball mill dispersion method, an attritor dispersion method, or a sand mill dispersion method can be used. In this case, it is effective to refine the particles to a particle size of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less.
<Charge transport layer>
When forming the charge transport layer of the function-separated type photoreceptor having the charge generation layer and the charge transport layer, a binder resin is used to ensure film strength.

In the case of the charge transport layer of the functional separation type photoconductor, a coating solution obtained by dissolving or dispersing the charge transport material and various binder resins in a solvent, or in the case of a single layer type photoconductor, the charge generation material and the charge transport It can be obtained by applying and drying a coating solution obtained by dissolving or dispersing the substance and various binder resins in a solvent.
<Binder resin>
Examples of the binder resin include polymers and copolymers of vinyl compounds such as butadiene resin, styrene resin, vinyl acetate resin, vinyl chloride resin, acrylic ester resin, methacrylic ester resin, vinyl alcohol resin, ethyl vinyl ether, and polyvinyl butyral. Resin, polyvinyl formal resin, partially modified polyvinyl acetal, polycarbonate resin, polyester resin, polyarylate resin, polyamide resin, polyurethane resin, cellulose ester resin, phenoxy resin, silicone resin, silicon-alkyd resin, poly-N-vinylcarbazole resin, etc. Can be given. These resins may be modified with a silicon reagent or the like. Of the binder resins, polyarylate resins are particularly preferable.

[Polyarylate resin]
The structure of the polyarylate resin contained in the photosensitive layer is exemplified below. This illustration is made for the purpose of clarifying the gist of the present invention, and is not limited to the illustrated structure unless it is contrary to the gist of the present invention. The polyarylate resin contained in the photosensitive layer contains, for example, the repeating structure represented by the general formula [1], and is produced by a known method, for example, with a divalent hydroxyaryl component and a dicarboxylic acid component. Can do.

In the general formula [1], Ar ^{1 to} Ar ⁴ may be the same or different, and each independently represents an arylene group which may have a substituent. The arylene group is not particularly limited, but is preferably an arylene group having 6 to 20 carbon atoms, and examples thereof include a phenylene group, a naphthylene group, an anthrylene group, a phenanthrylene group, and a pyrenylene group. Among these, a phenylene group and a naphthylene group are particularly preferable from the viewpoint of production cost. Further, when a phenylene group and a naphthylene group are compared, a phenylene group is more preferable in terms of ease of synthesis in addition to manufacturing cost. However, in the formula [1], when k = 0, when Ar3 and Ar4 are simultaneously unsubstituted arylene groups, the adhesive property of the photosensitive layer is poor, so either one of Ar3 and Ar4 has a substituent. An arylene group.

The substituent that may be independently present in the arylene group is not particularly limited, and preferred examples include a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, a condensed polycyclic group, and a halogen group. Considering the mechanical properties as the binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, the aryl group is preferably a phenyl group or a naphthyl group, and the halogen group is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. The alkoxy group is preferably a methoxy group, an ethoxy group, or a butoxy group. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and 1 to 2 carbon atoms. Are particularly preferable, and specifically, a methyl group is most preferable. The number of substituents for each of Ar ^{1 to} Ar ⁴ is not particularly limited, but is preferably 3 or less, more preferably 2 or less, and particularly preferably 1 or less.

Further, in the general formula [1], Ar ¹ and Ar ² are preferably the same arylene group having the same substituent, and particularly preferably an unsubstituted phenylene group. Ar ³ and A
r ^{4 is} also preferably the same arylene group, and particularly preferably a phenylene group having a methyl group.
In General Formula [1], X represents a divalent organic residue having a single bond, an oxygen atom, a sulfur atom, a structure represented by Formula [2], or a structure represented by Formula [3]. R ¹ and R ² in the formula [2] each independently represent a hydrogen atom, an alkyl group, or an aryl group, or a cycloalkylidene group formed by combining R ¹ and R ² . Examples of the alkyl group of R ¹ and R ² in the formula [2] include a methyl group, an ethyl group, a propyl group, and a butyl group, and examples of the aryl group include a phenyl group and a naphthyl group. In addition, examples of the cycloalkylidene group formed by combining R ¹ and R ² in the formula [2] include a cyclopentylidene group, a cyclohexylidene group, and a cycloheptylidene group. Furthermore, R ³ in the formula [3] represents an alkylene group, an arylene group, or a group represented by the formula [4]. Examples of the alkylene group represented by R ³ in the formula [3] include a methylene group, an ethylene group, and a propylene group. Examples of the arylene group represented by R ³ in the formula [3] include a phenylene group and a terphenylene group. Examples of the group represented by the formula [4] include a group represented by the following formula [8]. Among these, X is preferably an oxygen atom from the viewpoint of wear resistance.

In general formula [1], k is an integer of 0 to 5, preferably an integer of 0 to 1, and most preferably 1 from the viewpoint of wear resistance.
In general formula [1], Y represents a single bond, a sulfur atom, an oxygen atom, or a divalent organic residue having a structure represented by formula [5]. R ⁶ and R ⁷ in the formula [5] each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a cycloalkylidene group formed by combining R ⁶ and R ⁷ . Considering the mechanical properties as the binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, the aryl group is preferably a phenyl group or a naphthyl group, and the alkoxy group is preferably a methoxy group, an ethoxy group, or a butoxy group. preferable. Moreover, as an alkyl group, a C1-C10 alkyl group is preferable, More preferably, it is C1-C8, Most preferably, it is C1-2. Considering the simplicity of production of the divalent hydroxyaryl component used in producing the polyarylate resin, Y is a single bond, —O—, —S—, —CH ₂ —, —CH (CH ₃ ) —. , —C (CH ₃ ) ₂ — and cyclohexylidene are preferable, and —CH ₂ —, —CH (CH ₃ ) —, —C (CH ₃ ) ₂ — and cyclohexylidene are particularly preferable. Is —CH ₂ —, —CH (CH ₃ ) —.

In the present invention, the polyarylate resin is preferably a polyarylate resin containing a repeating structure represented by the following general formula [9]. In the following general formula [9], Ar ^{16 to} Ar ¹⁹ each independently represent an arylene group which may have a substituent, and R ⁸ represents a hydrogen atom or an alkyl group.

In the general formula [9], Ar ^{16 to} Ar ¹⁹ correspond to the Ar ^{1 to} Ar ⁴ respectively, and particularly preferably a phenylene group which may have a substituent. Moreover, as a preferable substituent, it is a hydrogen atom or an alkyl group, Most preferably, it is a methyl group. Further, in the general formula [9], Ar ¹⁸ and Ar ¹⁹ are the same phenylene group having a methyl group, and Ar ¹⁶ and Ar ¹⁷ are particularly preferably a phenylene group having no substituent. R ⁸ represents a hydrogen atom or an alkyl group, and the alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably a methyl group. .

  The divalent hydroxyaryl component to be a divalent hydroxyaryl residue in the polyarylate resin is represented by the following general formula [10], but is preferably represented by the following general formula [11].

Ar ³ , Ar ⁴ and Y in the general formula [10] are as described above.

Ar ¹⁸ and Ar ¹⁹ in the general formula [11] independently represent a phenylene group which may have a substituent, and R ⁸ represents a hydrogen atom or a methyl group.
Specifically, when R ⁸ in the general formula [11] is a hydrogen atom, bis (2-hydroxyphenyl) methane, (2-hydroxyphenyl) (3-hydroxyphenyl) methane, (2-hydroxyphenyl) ( 4-hydroxyphenyl) methane, bis (3-hydroxyphenyl) methane, (3-hydroxyphenyl) (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) methane, bis (2-hydroxy-3-methylphenyl) Methane, bis (2-hydroxy-3-ethylphenyl) methane, (2-hydroxy-3-methylphenyl) (3-hydroxy-4-methylphenyl) methane, (2-hydroxy-3-ethylphenyl) (3- Hydroxy-4-ethylphenyl) methane, (2-hydroxy-3-methylphenyl) (4-hydroxy) Cis-3-methylphenyl) methane, (2-hydroxy-3-ethylphenyl) (4-hydroxy-3-ethylphenyl) methane, bis (3-hydroxy-4-methylphenyl) methane, bis (3-hydroxy- 4-ethylphenyl) methane, (3-hydroxy-4-methylphenyl) (4-hydroxy-3-methylphenyl) methane, (3-hydroxy-4-ethylphenyl) (4-hydroxy-3-ethylphenyl) methane Bis (4-hydroxy-3-methylphenyl) methane, bis (4-hydroxy-3-ethylphenyl) methane. When R ⁸ is a methyl group, 1,1-bis (2-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) -1- (3-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) ) -1- (4-hydroxyphenyl) ethane, 1,1-bis (3-hydroxyphenyl) ethane, 1- (3-hydroxyphenyl) -1- (4-hydroxyphenyl) ethane, 1,1-bis ( 4-hydroxyphenyl) ethane, 1,1-bis (2-hydroxy-3-methylphenyl) ethane, 1,1-bis (2-hydroxy-3-ethylphenyl) ethane, 1- (2-hydroxy-3-) Methylphenyl) -1- (3-hydroxy-4-methylphenyl) ethane, 1- (2-hydroxy-3-ethylphenyl) -1- (3-hydroxy-4-ethylphenyl) Enyl) ethane, 1- (2-hydroxy-3-methylphenyl) -1- (4-hydroxy-3-methylphenyl) ethane, 1- (2-hydroxy-3-ethylphenyl) -1- (4-hydroxy) -3-ethylphenyl) ethane, 1,1-bis (3-hydroxy-4-methylphenyl) ethane, 1,1-bis (3-hydroxy-4-ethylphenyl) ethane, 1- (3-hydroxy-4) -Methylphenyl) -1- (4-hydroxy-3-methylphenyl) ethane, 1- (3-hydroxy-4-ethylphenyl) -1- (4-hydroxy-3-ethylphenyl) ethane, 1,1- Bis (4-hydroxy-3-methylphenyl) ethane and 1,1-bis (4-hydroxy-3-ethylphenyl) ethane are mentioned.

Among these, when R ⁸ in the general formula [11] is a hydrogen atom, bis (4-hydroxyphenyl) methane and (2-hydroxyphenyl) are considered in consideration of the ease of production of the divalent hydroxyaryl component. ) (4-hydroxyphenyl) methane, bis (2-hydroxyphenyl) methane, bis (4-hydroxy-3-methylphenyl) methane, bis (4-hydroxy-3-ethylphenyl) methane are particularly preferred. A combination of a plurality of divalent hydroxyaryl components can also be used.

In addition, when R ⁸ in the general formula [11] is a methyl group, 1,1-bis (4-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) -1- (4-hydroxyphenyl) ethane 1,1-bis (2-hydroxyphenyl) ethane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, and 1,1-bis (4-hydroxy-3-ethylphenyl) ethane are particularly preferable. These divalent hydroxyaryl components may be used in combination.

Although general formula [11] is contained in general formula [10], the compound of general formula [10] other than the illustration of the said general formula [11] is also demonstrated below.
Specific examples of the divalent hydroxyaryl component represented by the general formula [10] include 3,3 ′,
5,5′-tetramethyl-4,4′-dihydroxybiphenyl, 2,4,3 ′, 5′-tetramethyl-3,4′-dihydroxybiphenyl, 2,2 ′, 4,4′-tetramethyl- 3,3′-dihydroxybiphenyl, bis (4-hydroxy-3,5-dimethylphenyl) ether, (4-hydroxy-3,5-dimethylphenyl) (3-hydroxy-2,4-dimethylphenyl) ether, bis (3-hydroxy-2,4-dimethylphenyl) ether, bis (4-hydroxy-3,5-dimethylphenyl) methane, (4-hydroxy-3,5-dimethylphenyl) (3-hydroxy-2,4- Dimethylphenyl) methane, bis (3-hydroxy-2,4-dimethylphenyl) methane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) ethane 1- (4-hydroxy-3,5-dimethylphenyl)
-1- (3-hydroxy-2,4-dimethylphenyl) ethane, 1,1-bis (3-hydroxy-2,4-dimethylphenyl) ethane, 2,2-bis (4-hydroxy-3,5- Dimethylphenyl) propane, 2- (4-hydroxy-3,5-dimethylphenyl) -2- (3-hydroxy-2,4-dimethylphenyl) propane, 2,2-bis (3-hydroxy-2,4- Dimethylphenyl) propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane, 1- (4-hydroxy-3,5-dimethylphenyl) -1- (3-hydroxy-2,4- Dimethylphenyl) cyclohexane, 1,1-bis (3-hydroxy-2,4-dimethylphenyl) cyclohexane, preferably 3,3 ′, 5,5′-tetra Til-4,4′-dihydroxybiphenyl, bis (4-hydroxy-3,5-dimethylphenyl) ether, bis (4-hydroxy-3,5-dimethylphenyl) methane, 1,1-bis (4-hydroxy-) 3,5-dimethylphenyl) ethane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, and 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane. Alternatively, bis (2-hydroxyphenyl) ether, (2-hydroxyphenyl) (3-hydroxyphenyl) ether, (2-hydroxyphenyl) (4-hydroxyphenyl) ether, bis (3-hydroxyphenyl) ether, (3 -Hydroxyphenyl) (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) ether, bis (2-hydroxy-3-methylphenyl) ether, bis (2-hydroxy-3-ethylphenyl) ether, (2- Hydroxy-3-methylphenyl) (3-hydroxy-4-methylphenyl) ether, (2-hydroxy-3-ethylphenyl) (3-hydroxy-4-ethylphenyl) ether, (2-hydroxy-3-methylphenyl) ) (4-Hydroxy-3-methylphenyl) Ether, (2-hydroxy-3-ethylphenyl) (4-hydroxy-3-ethylphenyl) ether, bis (3-hydroxy-4-methylphenyl) ether, bis (3-hydroxy-4-ethylphenyl) ether, (3-hydroxy-4-methylphenyl) (4-hydroxy-3-methylphenyl) ether, (3-hydroxy-4-ethylphenyl) (4-hydroxy-3-ethylphenyl) ether, bis (4-hydroxy- 3-methylphenyl) ether, bis (4-hydroxy-3-ethylphenyl) ether, bis (4-hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane, bis (2- Hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) ether, bis (4-hydroxy -3-methylphenyl) methane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4- Hydroxy-3-methylphenyl) cyclohexane, bis (4-hydroxy-3-methylphenyl) ether, bis (4-hydroxy-3,5-dimethylphenyl) methane, 1,1-bis (4-hydroxy-3,5) -Dimethylphenyl) ethane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane, bis (4-hydroxy-2,3,5-trimethylphenyl) phenylmethane, 1,1-bis (4-hydroxy-2,3,5-trimethylphenyl) ) Phenylethane, bis (4-hydroxyphenyl) -1-phenylmethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) -1-phenylpropane Bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) methoxymethane, 1,1-bis (4-hydroxyphenyl) -1-methoxyethane, 1,1- Bis (4-hydroxyphenyl) -1-methoxypropane, bis (4-hydroxy Eniru) dimethoxymethane, and the like.

Of these, bis (4-hydroxy-3,5-dimethylphenyl) methane, 2,2-bis (4-hydroxy-3,5) are considered in consideration of the convenience of production of the divalent hydroxyaryl component.
-Dimethylphenyl) propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane, or bis (4-hydroxyphenyl) ether, (2-hydroxyphenyl) (4-hydroxyphenyl) ether, Bis (2-hydroxyphenyl) ether, bis (4-hydroxy-3-methylphenyl) ether, and bis (4-hydroxy-3-ethylphenyl) ether are particularly preferred, and a combination of these divalent hydroxyaryl components is used. It is also possible.

  The dicarboxylic acid component which is a dicarboxylic acid residue in the polyarylate resin is represented by the following general formula [12].

Ar ¹ , Ar ² , X, and k in the general formula [12] are as described above, and the dicarboxylic acid residues contained in the formula [12] are represented by the following general formulas [I] to [VI]. The structure is preferably exemplified by the following general formula [13].

Ar ¹⁶ and Ar ¹⁷ in the general formula [13] are also as described above, and are preferably phenylene groups which may have a substituent.
Specific examples of the preferred dicarboxylic acid residue include diphenyl ether-2,2′-dicarboxylic acid residue, diphenyl ether-2,3′-dicarboxylic acid residue, diphenyl ether-
Examples include 2,4′-dicarboxylic acid residue, diphenyl ether-3,3′-dicarboxylic acid residue, diphenyl ether-3,4′-dicarboxylic acid residue, diphenyl ether-4,4′-dicarboxylic acid residue. Among these, considering the simplicity of production of the dicarboxylic acid component, diphenyl ether-2,2′-dicarboxylic acid residue, diphenyl ether-2,4′-dicarboxylic acid residue, diphenyl ether-4,4′-dicarboxylic acid Residues are more preferred, and diphenyl ether-4,4′-dicarboxylic acid residues are particularly preferred.

The polyarylate resin contains another dicarboxylic acid component, and a part of the structure is represented by the general formula [1].
It may be a resin encapsulating. Specific examples of other dicarboxylic acid residues include adipic acid residues, suberic acid residues, sebacic acid residues, phthalic acid residues, isophthalic acid residues, terephthalic acid residues, toluene-2,5-dicarboxylic acid Residue, p-xylene-2,5-dicarboxylic acid residue, pyridine-2,3-dicarboxylic acid residue, pyridine-2,4-dicarboxylic acid residue, pyridine-2,5-dicarboxylic acid residue, pyridine -2,6-dicarboxylic acid residue, pyridine-3,4-dicarboxylic acid residue, pyridine-3,5-dicarboxylic acid residue, naphthalene-1,4-dicarboxylic acid residue, naphthalene-2,3-dicarboxylic acid An acid residue, naphthalene-2,6-dicarboxylic acid residue, biphenyl-2,2′-dicarboxylic acid residue, biphenyl-4,4′-dicarboxylic acid residue, preferably adipic acid residue, Seba Acid residue, phthalic acid residue, isophthalic acid residue, terephthalic acid residue, naphthalene-1,4-dicarboxylic acid residue, naphthalene-2,6-dicarboxylic acid residue, biphenyl-2,2′-dicarboxylic acid Acid residue, biphenyl-
It is a 4,4′-dicarboxylic acid residue, particularly preferably an isophthalic acid residue or a terephthalic acid residue. A combination of a plurality of these dicarboxylic acid residues can also be used.

  In addition, when it has the dicarboxylic acid residue constituting the present invention and the other dicarboxylic acid residues described above, the dicarboxylic acid residue constituting the present invention is preferably 70% or more as the number of repeating units, 80% or more is more preferable, and 90% or more is particularly preferable. Most preferably, it has only the dicarboxylic acid residue constituting the present invention, that is, the case where the dicarboxylic acid residue constituting the present invention is 100% as the number of repeating units.

  The polyarylate resin constituting the present invention can be mixed with other resins and used for an electrophotographic photosensitive member. Other resins used here include vinyl polymers such as polymethyl methacrylate, polystyrene, polyvinyl chloride, and copolymers thereof, polycarbonate, polyarylate, polyarylate polycarbonate, polysulfone, phenoxy, epoxy, silicone resin, etc. And other thermoplastic resins and various thermosetting resins. Of these resins, polycarbonate resin is preferable.

The mixing ratio of the resin to be used in combination is not particularly limited, but in order to sufficiently obtain the effects of the present invention, it is preferable to use the resin in combination within the range not exceeding the ratio of the polyarylate resin of the present invention. It is preferable not to use them together.
The viscosity average molecular weight of the polyarylate resin is not particularly limited, but is usually 10,000 or more, preferably 15,000 or more, more preferably 20,000 or more, but usually 300,000 or less, preferably 200. 1,000 or less, more preferably 100,000 or less. If the viscosity average molecular weight is excessively small, the mechanical strength of the photosensitive layer is lowered, which is not practical. On the other hand, if the viscosity average molecular weight is excessively large, it is difficult to apply and form the photosensitive layer to an appropriate film thickness.

<Charge transport material>
The energy level E_homo of HOMO by structure optimization calculation using B3LYP / 6-31G (d, p) of the first charge transport material of the present invention is E_homo> −4.67 (eV), and E_homo> −4.65 ( eV) is more preferred, and E_homo> −4.63 (eV) is most preferred. This is because the higher the HOMO energy level, the lower the post-exposure potential and the better the electrophotographic photoreceptor. On the other hand, if E_homo is too high, problems such as a decrease in gas resistance and the occurrence of ghosts occur, so usually E_homo <-4.30 (eV), E_homo <-4.50 (eV) is preferred, (eV) is more preferable.

Furthermore, the calculated value αcal of the polarizability α by the HF / 6-31G (d, p) calculation in the stable structure obtained after the structure optimization calculation using B3LYP / 6-31G (d, p) is αcal> 70 ( a Å ^3), more preferably ^{αcal> 80 (Å 3),} αcal> and most preferably from 90 (Å ^3). This is because a charge transport film containing a charge transport material having a large αcal exhibits high charge mobility, and by using the charge transport film, an electrophotographic photoreceptor excellent in chargeability and sensitivity can be obtained. Meanwhile, αcal
Is too large, the solubility of the charge transport material decreases, so αcal <200 (Å ³ ), preferably αcal <150 (Å ³ ), and αcal <130 (Å ³ ) Is more preferable, and αcal <110 (Å ³ ) is most preferable.

The first charge transport material that satisfies both E_homo> -4.67 (eV) and αcal> 70 (Å ³ )
It has the merits of the two parameter specifications as described above, has a low post-exposure potential, and is excellent in responsiveness, so that it can be used even in a low number of copies, so that the properties of the binder are not easily impaired.
In the present invention, the energy level E_homo of HOMO is a type of density functional B3LYP (AD Becke, J. Chem. Phys. 98, 5648 (1993), C. Lee, W. Yang, and RG Parr, Phys. Rev. B37, 785 (1988) and B. Miehlich, A. Savin, H. Stoll, and H. Preuss, Chem. Phys. Lett. 157, 200 (1989)). I got it. At this time, 6-31G (d, p) obtained by adding a polarization function to 6-31G was used as the basis set (R. Ditchfield, WJ Hehre, and JA Pople, J. Chem. Phys. 54, 724 (1971 ), WJ Hehre, R. Ditchfield, and JA Pople, J. Chem. Phys. 56, 2257 (1972), PC Hariharan and JA
Pople, Mol. Phys. 27, 209 (1974), MS Gordon, Chem. Phys. Lett. 76, 163 (1980),
PC Hariharan and JA Pople, Theo. Chim. Acta 28, 213 (1973), J.-P. Blaudeau, MP McGrath, LA Curtiss, and L. Radom, J. Chem. Phys. 107, 5016 (1997), MM Francl, WJ Pietro, WJ Hehre, JS Binkley, DJ DeFrees, JA Pople, and MS Gordon, J. Chem. Phys. 77, 3654 (1982), RC Binning Jr. and LA Curtiss, J. Comp. Chem. 11, 1206 (1990), VA Rassolov, JA Pople, MA Ratner, and TL Windus, J. Chem. Phys. 109, 1223 (1998), and VA Rassolov, MA Ratner, JA Pople, PC Redfern, and LA Curtiss, J. Comp. Chem. 22, 976 (2001)). In the present invention, B3LYP calculation using 6-31G (d, p) is described as B3LYP / 6-31G (d, p).

In addition, the polarizability αcal is calculated by the restricted Hartree-Fock method (“Modern Quantum Chemistry”, A. Szabo and NS Ostlund, McGraw) -See Hill publishing company, New York, 1989). At this time, 6-31G (d, p) was used as the basis function. In the present invention, the Hartree-Fock calculation using 6-31G (d, p) is described as HF / 6-31G (d, p).

In the present invention, the program used for B3LYP / 6-31G (d, p) calculation and HF / 6-31G (d, p) calculation is Gaussian 03, Revision D. 01 (MJ Frisch, GW Trucks, HB Schlegel, GE Scuseria, MA Robb, JR Cheeseman, JA Montgomery, Jr., T. Vreven, KN Kudin,
JC Burant, JM Millam, SS lyengar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N. Rega, GA Petersson, H. Nakatsuji, M. Hada, M. Ehara,
K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, JE Knox, HP Ilratchian, JB Cross, V . Bakken,
C. Adamo, J. Jaramillo, R. Gomperts, RE Stratmann, O. Yazyev, AJ Austin, R. Cammi, C. Pomelli, JW Ochterski, PY Ayala, K. Morokuma, GA Voth, P. Salvador, JJ Dannenberg, VG Zakrzewski, S. Dapprich, AD Daniels, MC Strain, O. Farkas, DK Malick, AD Rabuck, K. Raghavachari, JB Foresman, JV Ortiz, Q. Cui, AG Baboul, S. Clifford, J. Cioslowski, BB Stefanov , G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, RL Martin, DJ Fox, T. Keith,
(Ma Al-Laham, CY Peng, A. Nanayakkara, M. Challacombe, PMW Gill, B. Johnson, W. Chen, MW Wong, C. Gonzalez, and JA Pople, Gaussian, Inc., Wallingford CT, 2004.) is there.

The charge transport material having the parameters of the present invention, that is, the first charge transport material having the parameters of the present invention and the second charge transport material having the parameters of the present invention are outside the scope of the parameters of the present invention. However, in order to sufficiently exhibit the above-described effects of the present invention, the charge transport material having the parameters of the present invention is usually 10% by mass or more, preferably 50% by mass in the total charge transport material. As described above, more preferably 80% by mass or more, and most preferably 100% by mass.

There is no limitation on the structure of the first charge transport material satisfying the parameters of the present invention, and there are aromatic amine derivatives, stilbene derivatives, butadiene derivatives, hydrazone derivatives, carbazole derivatives, aniline derivatives, enamine derivatives, and a plurality of these compounds. Examples thereof include electron-donating materials such as a polymer having a bond or a group composed of these compounds in the main chain or side chain. Among these, aromatic amine derivatives, stilbene derivatives, hydrazone derivatives, enamine derivatives, and those in which a plurality of these compounds are bonded are preferable, and those in which a plurality of enamine derivatives and aromatic amines are bonded are more preferable. . Further, αcal tends to increase as the π-conjugated system spreads, and a structure in which the π-conjugated system spreads is preferable in consideration of planarity and steric effects due to substituents.

  In addition, the first charge transport material having the parameters of the present invention is usually 30 parts by mass or more, preferably 40 parts by mass with respect to 100 parts by mass of the binder resin in order to sufficiently exhibit the effects of the present invention described above. As mentioned above, More preferably, it is 50 mass parts or more. In addition, the charge transport material having the parameters of the present invention has an advantage that it can exert an effect even in a relatively small amount, and in view of wear resistance, it is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, most preferably Preferably it is 55 mass parts or less.

The energy level E_homo of HOMO by the structure optimization calculation using B3LYP / 6-31G (d, p) of the second charge transport material of the present invention is −5.0 <E_homo, and −4.82 <E_homo (eV) is Preferably, −4.79 <E_homo is more preferable. Further, E_homo <−4.67 (eV), E_homo <−4.68 is preferable, and E_homo <−4.70 (eV) is more preferable. The higher the energy level of HOMO,
This is because an excellent electrophotographic photosensitive member having a low potential after exposure can be obtained. On the other hand, if E_homo is too higher than the first charge transport material, the charge transport capability of the second charge transport material is inferior to that of the first charge transport material. May interfere with performance.
In the present invention, the second charge transport material has a function of increasing the universal hardness without adversely affecting the electrical characteristics of the photoreceptor and without significantly reducing the elastic deformation rate. The structure is not particularly limited, but Mw is usually 500 or less, preferably 400 or less, more preferably 350 or less. Usually, it is 90 or more, preferably 160 or more, and more preferably 240 or more.
When the Mw of the second charge transport material is small, the compatibility with the binder resin is increased, and the effect of increasing the universal hardness appears more remarkably.

In addition, the following general formula [1] is used to increase the universal hardness without significantly adversely affecting the electrical characteristics and without significantly lowering the elastic deformation rate, further suppress the shrinkage of the charge transport layer, and improve the adhesion. More preferably, the second charge transport material shown in [6] or [7] is contained in the photosensitive layer or each layer forming the same. In order to sufficiently exhibit the above-described effects of the present invention, the second charge transport material contained in the photosensitive layer is usually 100 parts by mass or less, preferably 50 parts by mass with respect to 100 parts by mass of the binder resin. Hereinafter, it is more preferably 30 parts by mass or less.

(In the general formula [6], Ar ⁶ and Ar ⁷ represent an aryl group having 10 or less carbon atoms constituting the aromatic ring, R represents a substituent other than hydrogen, and n represents an integer of 0 to 7. In [7], R ⁹ , R ¹⁰ and R ¹¹ each independently represent a hydrogen atom, an alkyl group, an alkoxy group or an aryl group, and R ¹⁰ and R ¹¹ are bonded to form a ring. May be good.)
In the above formula [6], Ar ¹ and Ar ² represent an aryl group having 10 or less carbon atoms constituting the aromatic ring. Here, the aryl group may have a substituent. Examples of the aryl group represented by Ar ¹ and Ar ² include a phenyl group and a naphthyl group. However, when the conjugated system is highly expanded by a substituent such as a condensed polycycle, the interaction between molecules becomes strong, and Since compatibility is lowered, at least one is preferably a phenyl group, and more preferably Ar ¹ , Ar
Both ² are preferably phenyl groups. Examples of the substituent that Ar ¹ and Ar ² may have include a hydrogen atom, a halogen atom, an alkyl group, a halogenated alkyl group, an aryl group, a halogenated aryl group, a heterocyclic group, a cyano group, a hydroxyl group, and a nitro group. Group, carboxyl group, sulfo group, amino group, alkoxy group, aryloxy group, alkylthio group, or arylthio group, etc., but durability against repeated use when used as an electrophotographic photoreceptor, durability against ozone and Considering having the characteristics of low residual potential, it has a lower alkyl group having 5 or less carbon atoms such as a methyl group, an ethyl group or a 2-propyl group, an alkoxy group having 5 or less carbon atoms such as a methoxy group or an ethoxy group. Is preferred. In particular, considering the mobility as a charge transport material, both Ar ¹ and Ar ² are more preferably phenyl groups having a substituent at the para position substituted by a nitrogen atom, and more preferably Ar ¹ and Ar ² are Are more preferably phenyl groups having a lower alkyl group having 5 or less carbon atoms or an alkoxy group having 5 or less carbon atoms in the para position substituted by a nitrogen atom, and more preferably both Ar ¹ and Ar ² are nitrogen atoms. It is preferably a phenyl group having a lower alkyl group having 3 or less carbon atoms or an alkoxy group having 3 or less carbon atoms in the para position substituted by the atom. Among the aryl groups and unsubstituted aryl groups having substituents, 4-methylphenyl group or 4-methoxyphenyl group is more suitable when considering the versatility of the reagent and the performance when used as an electrophotographic photoreceptor. preferable.

R is, for example, a halogen atom, alkyl group, halogenated alkyl group, aryl group, halogenated aryl group, heterocyclic group, cyano group, hydroxyl group, nitro group, carboxyl group, sulfo group, amino group, alkoxy group, aryloxy Group, an alkylthio group, an arylthio group, etc., considering that it has durability against repeated use when used as an electrophotographic photoreceptor, durability against ozone, and low residual potential characteristics, an alkyl group or an alkoxy group It is particularly preferably an alkyl group having 5 or less carbon atoms such as a methyl group, an ethyl group or a 2-propyl group, or an alkoxy group having 5 or less carbon atoms such as a methoxy group or an ethoxy group. Among these, considering mobility as a charge transport material, R is most preferably a methyl group or a methoxy group.

n represents the substitution number of R directly bonded to the naphthyl group, and represents an integer of 0 to 7. From the viewpoint of versatility of the raw material, 0 to 5 is preferable, 0 to 2 is particularly preferable, and 0 or 1 is most preferable.
When n ≧ 2, they may be bonded to each other to form a ring structure. In this case, the number of all carbon atoms of R to be bonded is preferably 5 or less, and particularly preferably 3 or less, for convenience in production. In the above formula [7], R ⁹ , R ¹⁰ , and R ¹ 1 is each independently a halogen atom, alkyl group, halogenated alkyl group, aryl group, halogenated aryl group, heterocyclic group, cyano group, hydroxyl group, nitro group, carboxyl group, sulfo group, amino group, alkoxy group, An aryloxy group, an alkylthio group, or an arylthio group is represented. From the viewpoint of the stability of the electrochemical compound, R ⁹ is preferably an alkyl group or an aryl group, and considering the steric congestion around the nitrogen atom of the carbazole group, it is more preferably an alkyl group, and preferably a methyl group. Most preferred. R ¹⁰ and R ¹¹ preferably have an aromatic ring from the viewpoint of electrical characteristics, more preferably an aralkyl group or an aryl group, and most preferably a phenyl group.

The first and second charge transport materials having the parameters of the present invention are particularly effective when a polyarylate resin having a repeating structure represented by the formula [1] is used. When polyarylate resin is used, the electrical characteristics are worse than when polycarbonate resin is used, but when using a charge transport material having the parameters of the present invention, both excellent wear resistance and electrical characteristics are achieved. be able to. A preferable structure of the polyarylate resin having a repeating structure represented by the formula [1] is the same as that described for the polyarylate resin.
Examples of charge transport materials are listed in Table 1 below.

In the case of a multilayer photoreceptor, the thickness of the charge transport layer is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more, and usually 50 μm or less from the viewpoint of long life, image stability, and high resolution. , Preferably 45 μm or less, more preferably 30 μm or less.
<Single layer type photosensitive layer>
The single-layer type photosensitive layer is formed using a binder resin in the same manner as the charge transport layer of the function-separated type photoreceptor in addition to the charge generation material and the charge transport material. Specifically, a charge generation material, a charge transport material, and various binder resins are dissolved or dispersed in a solvent to prepare a coating solution, and on a conductive support (on the undercoat layer when an undercoat layer is provided). It can be obtained by coating and drying.

The types of the charge transport material and the binder resin and the use ratios thereof are the same as those described for the charge transport layer of the multilayer photoreceptor. A charge generation material is further dispersed in a charge transport medium comprising these charge transport materials and a binder resin.
As the charge generation material, the same materials as those described for the charge generation layer of the multilayer photoreceptor can be used. However, in the case of a photosensitive layer of a single layer type photoreceptor, it is necessary to sufficiently reduce the particle size of the charge generating material. Specifically, the range is usually 1 μm or less, preferably 0.5 μm or less.

If the amount of the charge generating material dispersed in the single-layer type photosensitive layer is too small, sufficient sensitivity cannot be obtained, but if it is too large, there are adverse effects such as a decrease in chargeability and a decrease in sensitivity. The total amount of the layer-type photosensitive layer is usually 0.5% by mass or more, preferably 1% by mass or more, and usually 50% by mass or less, preferably 20% by mass or less.
In addition, the usage ratio of the binder resin and the charge generation material in the single-layer type photosensitive layer is such that the charge generation material is usually 0.1 parts by weight or more, preferably 1 part by weight or more, based on 100 parts by weight of the binder resin. It is 30 mass parts or less, Preferably it is set as the range of 10 mass parts or less.
The film thickness of the single-layer type photosensitive layer is usually 5 μm or more, preferably 10 μm or more, and usually 100 μm or less, preferably 50 μm or less.

In addition, in both the multilayer type photoreceptor and the single layer type photoreceptor, the film forming property, flexibility, coating property, stain resistance, gas resistance, light resistance, etc. are improved for the photosensitive layer or each layer constituting the photosensitive layer. For the purpose, a known antioxidant, plasticizer, ultraviolet absorber, electron-withdrawing compound, leveling agent, visible light shielding agent and the like may be contained.
<Other functional layers>
In a laminated or single layer type photoreceptor, a protective layer is provided on the outermost layer for the purpose of preventing the photosensitive layer from being worn and preventing or reducing the deterioration of the photosensitive layer due to discharge substances generated from a charger or the like. May be. The protective layer is formed by containing a conductive material in an appropriate binder resin, or charge transporting ability such as a triphenylamine skeleton as described in JP-A-9-190004 and JP-A-10-252377. The copolymer using the compound which has can be used.

Examples of the conductive material used for the protective layer include aromatic amino compounds such as TPD (N, N′-diphenyl-N, N′-bis- (m-tolyl) benzidine), antimony oxide, indium oxide, tin oxide, and oxide. Metal oxides such as titanium, tin oxide-antimony oxide, aluminum oxide, and zinc oxide can be used, but are not limited thereto.
As the binder resin used for the protective layer, known resins such as polyamide resin, polyurethane resin, polyester resin, epoxy resin, polyketone resin, polycarbonate resin, polyvinyl ketone resin, polystyrene resin, polyacrylamide resin, and siloxane resin can be used. Further, a copolymer of the above resin with a skeleton having a charge transporting ability such as a triphenylamine skeleton as described in JP-A-9-190004 can also be used.

The electrical resistance of the protective layer is usually in the range of 10 ⁹ Ω · cm to 10 ¹⁴ Ω · cm. When the electric resistance is higher than the range, the residual potential is increased, resulting in an image with much fogging. On the other hand, when the electric resistance is lower than the range, the image is blurred and the resolution is reduced. Further, the protective layer must be configured so as not to substantially prevent transmission of light irradiated during image exposure.
Further, for the purpose of reducing the frictional resistance and wear on the surface of the photoconductor, and increasing the transfer efficiency of the toner from the photoconductor to the transfer belt and paper, etc., the surface layer is made of a fluororesin, silicone resin, polyethylene resin, or the like. You may contain the particle | grains which consist of these resin, and the particle | grains of an inorganic compound. Alternatively, a layer containing these resins and particles may be newly formed as a surface layer.

<Method for forming each layer>
Each layer constituting the above-described photoreceptor is formed by dip coating, spray coating, nozzle coating, bar coating, roll coating, blade coating on a conductive support obtained by dissolving or dispersing a substance to be contained in a solvent. It is formed by repeating a coating / drying step sequentially for each layer by a known method such as coating.

  There are no particular restrictions on the solvent or dispersion medium used for the preparation of the coating solution, but specific examples include alcohols such as methanol, ethanol, propanol and 2-methoxyethanol, tetrahydrofuran, 1,4-dioxane, dimethoxyethane and the like. Ethers, esters such as methyl formate and ethyl acetate, acetone, methyl ethyl ketone, cyclohexanone, ketones such as 4-methoxy-4-methyl-2-pentanone, aromatic hydrocarbons such as benzene, toluene, xylene, dichloromethane, Chlorinated hydrocarbons such as chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, trichloroethylene, n-butylamine, isopropanolamine, Diethyl Min, triethanolamine, ethylenediamine, nitrogen-containing compounds such as triethylenediamine, acetonitrile, N- methylpyrrolidone, N, N- dimethylformamide, aprotic polar solvents such as dimethyl sulfoxide and the like. Moreover, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and kinds.

The amount of the solvent or the dispersion medium used is not particularly limited, but considering the purpose of each layer and the properties of the selected solvent / dispersion medium, it is appropriately determined so that the physical properties such as the solid content concentration and viscosity of the coating liquid are within a desired range. It is preferable to adjust.
For example, in the case of a charge transport layer of a single layer type photoreceptor or a function separation type photoreceptor, the solid content concentration of the coating solution is usually 5% by mass or more, preferably 10% by mass or more, and usually 40% by mass or less. The range is preferably 35% by mass or less. In addition, the viscosity of the coating solution is usually 10 mPa · s or higher, preferably 50 mPa · s or higher, and usually 500 mPa · s or lower, preferably 400 mPa · s or lower, at the temperature during use.

  In the case of a charge generation layer of a multilayer photoreceptor, the solid content concentration of the coating solution is usually 0.1% by mass or more, preferably 1% by mass or more, and usually 15% by mass or less, preferably 10% by mass. % Or less. In addition, the viscosity of the coating solution is usually 0.01 mPa · s or higher, preferably 0.1 mPa · s or higher, and usually 20 mPa · s or lower, preferably 10 mPa · s or lower, at the temperature during use.

  Each layer constituting these photoconductors is formed by applying the coating solution obtained by the above-described method on a support using a known coating method, repeating the coating and drying steps for each layer, and sequentially coating the layers. The Examples of the coating method include a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method, an air knife coating method, and a curtain coating method. Other known coating methods can also be used.

The coating solution is preferably dried by touching at room temperature, followed by heating or drying in a temperature range of usually 30 ° C. or more and 200 ° C. or less for 1 minute to 2 hours, while still or blowing. Further, the heating temperature may be constant, or heating may be performed while changing the temperature during drying.
<Universal hardness and elastic deformation rate>
The universal hardness in the present invention is usually 190 N / mm ² or more, preferably 200 N / mm ² or more, more preferably 210 N / mm ² or more, while usually 500 N / mm ² or less, preferably 350 N / mm ² or less, and more preferably not more than 290 N / mm ^2. By setting the universal hardness in the above range, it is possible to suppress the sounding during printing. The elastic deformation rate in the present invention is usually 45% or more, more preferably 46.5% or more, while it is usually 100% or less, preferably 60% or less, more preferably 50% or less. By setting the elastic deformation rate in the above range, the close contact with the cleaning member is improved, and it is possible to suppress the occurrence of poor cleaning and the occurrence of filming even when toner having a high degree of circularity is used.
The universal hardness and elastic deformation rate in the present invention are values measured using a micro hardness tester (Fischer: FISCHERSCOPE H100C) in an environment of a temperature of 25 ° C. and a relative humidity of 50%. A Vickers square pyramid diamond indenter with a facing angle of 136 ° is used for the measurement. The measurement conditions are set as follows, and the load applied to the indenter and the indentation depth under the load are continuously read, and profiles as shown in FIG. 2 plotted on the Y axis and X axis are obtained.

[Measurement condition]
Maximum pushing load 5mN
Load time 10s
Unloading time 10s
In the present invention, the universal hardness is a value when the indentation load is indented to 5 mN, and is a value defined by the following formula from the indentation depth.
Universal hardness (N / mm ² ) = Test load (N) / Surface area of Vickers indenter under test load (mm ² )
The elastic deformation rate in the present invention is a value defined by the following equation, and is a ratio of work that the film performs by elasticity at the time of unloading with respect to the total work amount required for pushing.
Elastic deformation rate (%) = (We / Wt) × 100
In the above formula, the total work Wt (nJ) indicates the area surrounded by ABDA in FIG. 2, and the elastic deformation work We (nJ) indicates the area surrounded by CBDC. As the elastic deformation rate is larger, the deformation with respect to the load is less likely to remain.

  As long as the photoreceptor has universal hardness and elastic deformation rate within the scope of the present invention, the configuration is not limited, but the resin described in the section of [Polyarylate resin] is preferably used. The preferred range when using a polyarylate resin is the same as that described in the section of [Polyarylate resin]. When a k = 1 resin of the compound represented by the formula [1] is used as the polyarylate resin, the elastic deformation rate shows a particularly preferable value.

<Toner>
When an image is formed using the electrophotographic photosensitive member of the present invention, a toner as a developer is used to develop a latent image. By using the toner as described above, the image forming apparatus of the present invention can form a high-quality image.
<Toner circularity>
The shape of the toner is such that the shape of each particle contained in the particle group constituting the toner is closer to each other, and the closer to a sphere, the less the localization of the charge amount in the toner particles and the more developability. It tends to be uniform, which is preferable for improving image quality. In particular, if the toner has a shape close to a perfect sphere, the contact area with the electrophotographic photosensitive member may be reduced, the toner transfer rate may be increased, and the toner consumption may be reduced. . On the other hand, it is difficult to manufacture a perfect spherical toner, and the cost of the toner increases. Therefore, it is sufficient that the toner is close to a sphere under a certain condition, and it is not necessary to be a perfect sphere.

  Therefore, specifically, the toner has an average circularity measured by a flow particle image analyzer of usually 0.940 or more, preferably 0.945 or more, more preferably 0.950 or more, and still more preferably 0. .955 or more, particularly preferably 0.960 or more. The upper limit of the average circularity is not limited as long as it is 1.000 or less, but is preferably 0.998 or less, more preferably 0.995 or less from the viewpoint of ease of production.

The average circularity is used as a simple method for quantitatively expressing the shape of toner particles. In the present invention, the flow type particle image analyzer FPIA-20 manufactured by Sysmex Corporation is used.
The measurement is performed using 00, and the circularity [a] of the measured particle is obtained by the following equation (X).
Circularity a = L0 / L (X)
(In Formula (X), L0 represents the perimeter of a circle having the same projected area as the particle image, and L represents the perimeter of the particle image when image processing is performed.)
The circularity is an index of the degree of unevenness of toner particles, and indicates 1.000 when the toner is a perfect sphere, and the circularity becomes smaller as the surface shape becomes more complicated.

  A specific method for measuring the average circularity is as follows. That is, a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 20 mL of water from which impurities in the container have been removed in advance, and about 0.05 g of a measurement sample (toner) is further added. The suspension in which this sample is dispersed is irradiated with ultrasonic waves for 30 seconds, and the dispersion concentration is set to 3.0 to 8.0 thousand pieces / μL (microliter). The circularity distribution of particles having an equivalent circle diameter of 60 μm or more and less than 160 μm is measured.

<Toner type>
The toner is not limited as long as it has the above average circularity. Various types of toner are usually obtained depending on the production method, and any toner can be used.
Hereinafter, the toner manufacturing method and the type of toner will be described.

The toner may be produced by any conventionally known method, for example, a toner produced by a polymerization method, a melt suspension method, or the like. Furthermore, a so-called pulverized toner is formed into a sphere by treatment with heat or the like. However, a toner produced by a so-called polymerization method that generates toner particles in an aqueous medium is preferable.
As a method for producing a toner by a so-called polymerization method, a direct toner is used by using a suspension polymerization method described in JP-B-36-10231, JP-A-59-53856, and JP-A-59-61842. To form a toner, a dispersion polymerization method in which a monomer is soluble in a water-based organic solvent insoluble in a polymer, or a direct polymerization in the presence of a water-soluble polar polymerization initiator to produce a toner. The toner can be produced using an emulsion polymerization method represented by a soap-free polymerization method. Examples of the polymerization toner include suspension polymerization toner and emulsion polymerization aggregation toner.

  In order to improve the releasability, low-temperature fixing property, high-temperature offset property, filming resistance and the like of the toner, a method of incorporating a low softening point substance (so-called wax) into the toner has been proposed. In the melt-kneading pulverization method, it is difficult to increase the amount of wax contained in the toner, and the limit is about 5% by mass with respect to the polymer (binder resin). In contrast, the polymerized toner can contain a low softening point substance in a large amount (5 to 30% by mass). The polymer here is one of the materials constituting the toner. For example, in the case of a toner manufactured by an emulsion polymerization aggregation method described later, the polymer is obtained by polymerizing a polymerizable monomer.

As a method for obtaining a toner having a fine particle size of 3 to 8 μm with a sharp particle size distribution that can control the average circularity of the toner to 0.940 or more, for example, suspension under normal pressure or under pressure is used. Examples thereof include a turbid polymerization method and an emulsion polymerization aggregation method.
When manufacturing toner using the suspension polymerization method, the specific method for embedding the low softening point substance is to set the polarity of the substance in the aqueous medium smaller than that of the main monomer. In addition, a toner having a so-called core / shell structure in which a low softening point substance is coated with an outer shell resin can be obtained by adding a small amount of a highly polar resin or monomer. Toner particle size distribution control and particle size control can be done by changing the type and amount of a poorly water-soluble inorganic salt or dispersant that acts as a protective colloid, as well as mechanical equipment conditions, such as rotor speed, number of passes, A predetermined toner can be obtained by controlling the stirring conditions such as the shape of the stirring blade, the container shape, or the solid content concentration in the aqueous solution.

As the outer shell resin of the toner used in the present invention, generally used styrene- (meth) acrylic copolymers, polyester resins, epoxy resins, and styrene-butadiene copolymers can be used. Those monomers are preferably used in a method for directly obtaining a toner by a polymerization method.
Specifically, styrene monomers such as styrene, o (m-, p-)-methylstyrene, m (p-)-ethylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate, ( Meth) propyl acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (Meth) acrylic acid ester monomers such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; ene monomers such as butadiene, isoprene, cyclohexene, (meth) acrylonitrile, and acrylamide Is preferably used.

  These monomers are used alone or generally so that the theoretical glass transition temperature (Tg) described in the publication polymer handbook 2nd edition III-P139-192 (John Wiley & Sons) is 40-75 ° C. It is used by mixing appropriately. When the theoretical glass transition temperature is less than 40 ° C., there are problems in terms of storage stability of the toner and durability of the developer. On the other hand, when it exceeds 75 ° C., the fixing point is increased. In some cases, the color toners are not sufficiently mixed, resulting in poor color reproducibility. Further, the transparency of the OHP image is remarkably lowered, which is not preferable from the viewpoint of high image quality.

  The molecular weight of the outer shell resin is measured by GPC (gel permeation chromatography). As a specific GPC measurement method, a toner is previously extracted with a toluene solvent using a Soxhlet extractor for 20 hours, and then toluene is distilled off with a rotary evaporator. Further, the low softening point substance is dissolved, but the shell resin is used. After washing thoroughly with an organic solvent that cannot be dissolved, such as chloroform, a sample obtained by filtering a solution soluble in THF (tetrahydrofuran) with a solvent-resistant membrane filter having a pore size of 0.3 μm was manufactured by Waters. Using 150C, the column configuration can be measured by using A-801, 802, 803, 804, 805, 806, and 807 manufactured by Showa Denko and using a standard polystyrene resin calibration curve to measure the molecular weight distribution.

The number average molecular weight (Mn) of the obtained resin component is 5000 to 1000000, and the ratio (Mw / Mn) of the mass average molecular weight (Mw) to the number average molecular weight (Mn) is 2 to 100. Is preferred for the present invention.
In the present invention, when a toner having a core / shell structure is produced, it is particularly preferable to add a polar resin in addition to the outer shell resin in order to encapsulate the low softening point substance with the outer shell resin. As the polar resin used in the present invention, a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, a saturated polyester resin, and an epoxy resin are preferably used. The polar resin is particularly preferably one containing no unsaturated group capable of reacting with the shell resin or monomer in the molecule. If a polar resin having an unsaturated group is included, a crosslinking reaction occurs with the monomer that forms the shell resin layer. It is not preferable.

In the present invention, the outermost resin layer may be provided by superposition on the surface of the toner having an outer shell structure by a polymerization method.
The glass transition temperature of the outermost shell resin layer is designed to be higher than the glass transition temperature of the outer shell resin layer for further improvement of block king resistance, and is further crosslinked to such an extent that the fixing property is not impaired. Is preferred. Further, the outermost resin layer preferably contains a polar resin or a charge control agent in order to improve chargeability.

Further, the method for providing the outermost shell resin layer is not particularly limited, and examples thereof include the following methods.
1. In the latter half of the polymerization reaction or after completion, if necessary, add a monomer in which a polar resin, charge control agent, cross-linking agent, etc. are dissolved and dispersed in the reaction system and adsorb to the polymer particles, and then add a polymerization initiator to perform polymerization. How to do.
2. If necessary, emulsion-polymerized particles or soap-free polymerized particles consisting of monomers containing a polar resin, a charge control agent, a crosslinking agent, etc. are added to the reaction system and aggregated on the surface of the polymerized particles. How to fix.
3. A method in which emulsion-polymerized particles or soap-free polymerized particles comprising monomers containing a polar resin, a charge control agent, a crosslinking agent, etc. are mechanically fixed to the toner particle surface in a dry manner as required.

  As the colorant used in the present invention, carbon black, a magnetic material, and a black colorant that is toned in black using the following yellow / magenta / cyan colorant are used. As the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 168, etc. are preferably used.

  As the magenta colorant, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds are used. Specifically, C.I. I. Pigmentlets 2,3,5,6,7,23,48; 2,48; 3,48; 4,57; 1,81; 1,144,146,166,169,177,184,185,202, 206, 220, 221, 254 are particularly preferred.

  As the cyan colorant used in the present invention, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like can be used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15; 3, 15: 4, 60, 62, 66 and the like can be used particularly preferably. These colorants can be used alone or mixed and further used in the form of a solid solution.

In the case of a color toner, the colorant of the present invention is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP transparency, and dispersibility in the toner. The colorant is added in an amount of 1 to 20 parts by mass with respect to 100 parts by mass of the resin. When a magnetic material is used as the black colorant, 40 to 150 parts by mass are added to 100 parts by mass of the resin, unlike other colorants.
As the charge control agent used in the present invention, known ones can be used. In the case of a color toner, in particular, a charge control agent that is colorless, has a high toner charging speed, and can stably maintain a constant charge amount. preferable. Further, when the direct polymerization method is used in the present invention, a charge control agent having no polymerization inhibition and no solubilized product in an aqueous system is particularly preferable.

Specific examples of the negative compounds include salicylic acid, naphthoic acid, dicarboxylic acid metal compounds, sulfonic acid, polymer compounds having carboxylic acid in the side chain, boron compounds, urea compounds, silicon compounds, calixarene, and the like. As a positive system, a quaternary ammonium salt, a polymer compound having the quaternary ammonium salt in the side chain, a guanidine compound, an imidazole compound, and the like are preferably used. The charge control agent is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the resin. However, the addition of a charge control agent is not essential in the present invention.

  When the direct polymerization method is used in the present invention, examples of the polymerization initiator include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, , 1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, Peroxide polymerization initiators such as methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide are used.

The addition amount of the polymerization initiator varies depending on the desired degree of polymerization, but generally 0.5 to 20% by mass is added to the monomer. The kind of the initiator is slightly different depending on the polymerization method, but can be used alone or mixed with reference to the 10-hour half-life temperature. In order to control the degree of polymerization, a known crosslinking agent, chain transfer agent, polymerization inhibitor and the like can be further added and used.
When suspension polymerization is used as a toner production method used in the present invention, as a dispersant to be used, for example, as an inorganic oxide, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate , Magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, magnetic substance, ferrite and the like. As the organic compound, for example, polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, sodium salt of ethyl cellulose C carboxymethyl cellulose, starch and the like are used by dispersing in an aqueous phase. These dispersants are preferably used in an amount of 0.2 to 10.0 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

  Commercially available dispersants may be used as they are, but in order to obtain dispersed particles having a fine and uniform particle size, the inorganic compound can be produced in a dispersion medium under high-speed stirring. For example, in the case of tricalcium phosphate, a dispersant preferable for the suspension polymerization method can be obtained by mixing an aqueous sodium phosphate solution and an aqueous calcium chloride solution under high-speed stirring. Moreover, you may use together 0.001-0.1 mass part surfactant for refinement | miniaturization of these dispersing agents. Specifically, commercially available nonionic, anionic and cationic surfactants can be used, for example, sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, Calcium oleate is preferably used.

  When the direct polymerization method is used as the toner production method used in the present invention, the toner can be specifically produced by the following production method. Monomer composition in which a release agent, colorant, charge control agent, polymerization initiator and other additives consisting of a low softening substance are added to the monomer and dissolved or dispersed uniformly by a homogenizer, ultrasonic disperser, etc. The product is dispersed in an aqueous phase containing a dispersion stabilizer by a usual stirrer, homomixer, homogenizer or the like. Preferably, granulation is performed by adjusting the stirring speed and time so that droplets of the monomer composition have a desired toner particle size. Thereafter, stirring may be performed to such an extent that the particle state is maintained and the sedimentation of the particles is prevented by the action of the dispersion stabilizer.

  Polymerization is carried out at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. In addition, the temperature may be raised in the latter half of the polymerization reaction, and for the purpose of improving durability characteristics, in order to remove unreacted polymerizable monomers, by-products, etc. The aqueous medium may be distilled off. After completion of the reaction, the produced toner particles are recovered by washing and filtration and dried. In the suspension polymerization method, it is usually preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to 100 parts by weight of the monomer system.

Further, the toner in the present invention may be classified to control the particle size distribution, and as a method therefor, a multi-division classifying device using inertial force is preferably used. By using this apparatus, the toner having the particle size distribution of the present invention can be produced efficiently.
When a toner is produced by an emulsion polymerization aggregation method, the production process usually includes a polymerization process, a mixing process, an aggregation process, a fusion process, and a washing / drying process. That is, generally, polymer primary particles are obtained by emulsion polymerization (polymerization step), and if necessary, a colorant (pigment), wax, charge control agent, etc. are dispersed in a dispersion containing the polymer primary particles. The body is mixed (mixing step), and a coagulant is added to the dispersion to agglomerate the primary particles to form a particle aggregate (aggregation step). Thus, particles are obtained (fusion process), and the obtained particles are washed and dried (washing / drying process) to obtain mother particles.

<Polymerization process>
The polymer fine particles (polymer primary particles) are not particularly limited. Therefore, either a fine particle obtained by polymerizing a polymerizable monomer in a liquid medium by a suspension polymerization method, an emulsion polymerization method or the like, or a fine particle obtained by pulverizing a lump of a polymer such as a resin is a polymer. It may be used as primary particles. However, a polymerization method, particularly an emulsion polymerization method, in particular, a method using wax as a seed in emulsion polymerization is preferable. When wax is used as a seed in emulsion polymerization, fine particles having a structure in which the polymer wraps the wax can be produced as polymer primary particles. According to this method, the wax can be contained in the toner without being exposed on the surface of the toner. For this reason, there is no contamination of the apparatus member by the wax, the chargeability of the toner is not impaired, and the low temperature fixing property, high temperature offset property, filming resistance, releasability, etc. of the toner can be improved. it can.

Hereinafter, a method of performing emulsion polymerization using wax as a seed, thereby obtaining polymer primary particles will be described.
The emulsion polymerization method may be performed according to a conventionally known method. Usually, a wax is dispersed in a liquid medium in the presence of an emulsifier to form wax fine particles, and a polymerization initiator that gives a polymer by polymerization (that is, a polymerizable carbon-carbon double bond). And a chain transfer agent, a pH adjuster, a polymerization degree adjuster, an antifoaming agent, a protective colloid, an internal additive, and the like, if necessary, and polymerized by stirring. As a result, an emulsion is obtained in which polymer fine particles (that is, polymer primary particles) having a structure in which the polymer wraps the wax are dispersed in the liquid medium. Examples of the structure in which the polymer wraps the wax include a core-shell type, a phase separation type, and an occlusion type, and the core-shell type is preferable.

(I. Wax)
As the wax, any known wax that can be used for this purpose can be used. For example, olefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene and copolymer polyethylene; paraffin wax; silicone wax having an alkyl group; fluororesin wax such as low molecular weight polytetrafluoroethylene; higher fatty acids such as stearic acid; eicosanol Long-chain aliphatic alcohols such as behenate behenate, montanic acid ester, stearic acid ester ester wax having a long-chain aliphatic group; distearyl ketone and other long-chain alkyl group ketones; hydrogenated castor oil, Plant waxes such as carnauba wax; esters or partial esters obtained from polyhydric alcohols such as glycerin and pentaerythritol and long chain fatty acids; higher fatty acid amides such as oleic acid amide and stearic acid amide; Ester and the like. Especially, what has at least 1 the endothermic peak by a differential thermal analysis (DSC) in 50-100 degreeC is preferable.

Among the waxes, for example, ester waxes, paraffin waxes, olefin waxes such as low molecular weight polypropylene and copolymer polyethylene, silicone waxes, and the like are preferable because a release effect can be obtained in a small amount. Paraffin wax is particularly preferable. In addition, 1 type may be used for wax and it may use 2 or more types together by arbitrary combinations and a ratio.

  When using wax, the amount used is arbitrary. However, it is desirable that the wax is usually 3 parts by mass or more, preferably 5 parts by mass or more, and usually 40 parts by mass or less, preferably 30 parts by mass or less with respect to 100 parts by mass of the polymer. If the amount of wax is too small, the fixing temperature range may be insufficient. If the amount is too large, the apparatus member may be contaminated and image quality may be deteriorated.

(Ii. Emulsifier)
There is no restriction | limiting in an emulsifier, Arbitrary things can be used in the range which does not impair the effect of this invention remarkably. For example, any of nonionic, anionic, cationic and amphoteric surfactants can be used.
Examples of the nonionic surfactant include polyoxyalkylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyalkylene alkyl phenyl ethers such as polyoxyethylene octylphenyl ether, and sorbitan fatty acid esters such as sorbitan monolaurate. And the like.

Examples of the anionic surfactant include fatty acid salts such as sodium stearate and sodium oleate, alkylaryl sulfonates such as sodium dodecylbenzene sulfonate, and alkyl sulfate salts such as sodium lauryl sulfate. .
Furthermore, examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and quaternary ammonium salts such as lauryltrimethylammonium chloride.

Examples of amphoteric surfactants include alkylbetaines such as lauryl betaine.
Among these, nonionic surfactants and anionic surfactants are preferable. In addition, 1 type may be used for an emulsifier and it may use 2 or more types together by arbitrary combinations and a ratio.
Furthermore, the amount of the emulsifier is arbitrary as long as the effects of the present invention are not significantly impaired.

(Iii. Liquid medium)
As the liquid medium, an aqueous medium is usually used, and water is particularly preferably used. However, the quality of the liquid medium is also related to the coarsening due to reaggregation of particles in the liquid medium. When the conductivity of the liquid medium is high, the dispersion stability with time tends to deteriorate. Therefore, when an aqueous medium such as water is used as the liquid medium, it is preferable to use ion-exchanged water or distilled water that has been desalted so that the electrical conductivity is usually 10 μS / cm or less, preferably 5 μS / cm or less. preferable. The conductivity is measured at 25 ° C. using a conductivity meter (a personal SC meter model SC72 and a detector SC72SN-11 manufactured by Yokogawa Electric Corporation).

Moreover, there is no restriction | limiting in the usage-amount of a liquid medium, However, The quantity of about 1-20 mass times is normally used with respect to a polymerizable monomer.
By dispersing the wax in the liquid medium in the presence of an emulsifier, fine wax particles are obtained. The order of blending the emulsifier and the wax in the liquid medium is arbitrary, but usually the emulsifier is first blended in the liquid medium and then the wax is mixed. Moreover, you may mix | blend an emulsifier with a liquid medium continuously.

(Iv. Polymerization initiator)
After preparing the wax fine particles, a polymerization initiator is blended in the liquid medium. Any polymerization initiator can be used as long as the effects of the present invention are not significantly impaired. For example, persulfates such as sodium persulfate and ammonium persulfate; organic peroxides such as t-butyl hydroperoxide, cumene hydroperoxide and p-menthane hydroperoxide; inorganics such as hydrogen peroxide Examples include peroxides. Of these, inorganic peroxides are preferable. In addition, 1 type may be used for a polymerization initiator and it may use 2 or more types together by arbitrary combinations and a ratio.

In addition, other examples of the polymerization initiator include persulfates, organic or inorganic peroxides, and reducing organic compounds such as ascorbic acid, tartaric acid, citric acid, sodium thiosulfate, sodium bisulfite, metabisulfate. A redox initiator can also be used in combination with reducing inorganic compounds such as sodium sulfite. In this case, reducing inorganic compounds may be used alone or in combination of two or more in any combination and ratio.
Moreover, there is no restriction | limiting in the usage-amount of a polymerization initiator, It is arbitrary. However, a polymerization initiator is normally used in the ratio of 0.05-2 mass parts with respect to 100 mass parts of polymerizable monomers.

(V. Polymerizable monomer)
After the wax fine particles are prepared, a polymerizable monomer is blended in the liquid medium in addition to the polymerization initiator. There is no particular limitation on the polymerizable monomer, but for example, styrenes, (meth) acrylic acid esters, acrylamides, monomers having Bronsted acidic groups (hereinafter simply referred to as “acidic monomers”) ), A monofunctional monomer such as a monomer having a Bronsted basic group (hereinafter sometimes simply referred to as “basic monomer”). Further, a monofunctional monomer can be used in combination with a polyfunctional monomer.

Examples of styrenes include styrene, methyl styrene, chlorostyrene, dichlorostyrene, p-tert-butyl styrene, pn-butyl styrene, pn-nonyl styrene, and the like.
Examples of the (meth) acrylic acid ester include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, 2-ethylhexyl acrylate, and methyl methacrylate. , Ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hydroxyethyl methacrylate, and 2-ethylhexyl methacrylate.

Examples of acrylamides include acrylamide, N-propyl acrylamide, N, N-dimethyl acrylamide, N, N-dipropyl acrylamide, N, N-dibutyl acrylamide, and the like.
Furthermore, examples of the acidic monomer include monomers having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, fumaric acid and cinnamic acid; monomers having a sulfonic acid group such as sulfonated styrene; vinylbenzenesulfonamide and the like. Examples thereof include a monomer having a sulfonamide group.

Examples of the basic monomer include aromatic vinyl compounds having an amino group such as aminostyrene, nitrogen-containing heterocycle-containing monomers such as vinylpyridine and vinylpyrrolidone; amino groups such as dimethylaminoethyl acrylate and diethylaminoethyl methacrylate. Examples include (meth) acrylic acid esters.
In addition, the acidic monomer and the basic monomer may exist as a salt with a counter ion.

Furthermore, as the polyfunctional monomer, for example, divinylbenzene, hexanediol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, Examples include diallyl phthalate. It is also possible to use a monomer having a reactive group such as glycidyl methacrylate, N-methylolacrylamide, or acrolein. Among these, radically polymerizable bifunctional monomers, particularly divinylbenzene and hexanediol diacrylate are preferable.

  Among these, the polymerizable monomer is preferably composed of at least styrenes, (meth) acrylic acid esters, and acidic monomers having a carboxyl group. In particular, styrene is preferred as the styrene, butyl acrylate is preferred as the (meth) acrylic acid ester, and acrylic acid is preferred as the acidic monomer having a carboxyl group.

In addition, 1 type may be used for a polymerizable monomer and it may use 2 or more types together by arbitrary combinations and a ratio.
When emulsion polymerization is performed using wax as a seed, it is preferable to use an acidic monomer or a basic monomer and a monomer other than these in combination. This is because the dispersion stability of the polymer primary particles can be improved by using an acidic monomer or a basic monomer in combination.

  At this time, the compounding amount of the acidic monomer or basic monomer is arbitrary, but the amount of the acidic monomer or basic monomer used is usually 0.05 parts by mass or more, preferably 0 with respect to 100 parts by mass of the total polymerizable monomer. It is desirable that the amount be 5 parts by mass or more, more preferably 1 part by mass or more, and usually 10 parts by mass or less, preferably 5 parts by mass or less. If the blending amount of the acidic monomer or basic monomer is below the above range, the dispersion stability of the polymer primary particles may be deteriorated, and if it exceeds the upper limit, the chargeability of the toner may be adversely affected.

  Moreover, when using a polyfunctional monomer together, the compounding quantity is arbitrary, However, The compounding quantity of the polyfunctional monomer with respect to 100 mass parts of polymerizable monomers is 0.005 mass part or more normally, Preferably it is 0.00. 1 part by mass or more, more preferably 0.3 part by mass or more, and usually 5 parts by mass or less, preferably 3 parts by mass or less, more preferably 1 part by mass or less. By using a polyfunctional monomer, the fixability of the toner can be improved. At this time, if the blending amount of the polyfunctional monomer is below the above range, the high temperature offset resistance may be inferior, and if it exceeds the upper limit, the low temperature fixability may be inferior.

  The method for blending the polymerizable monomer into the liquid medium is not particularly limited. For example, any of batch addition, continuous addition, and intermittent addition may be used, but it is preferable to blend continuously from the viewpoint of reaction control. Moreover, when using several polymerizable monomer together, each polymerizable monomer may be mix | blended separately, and may be mix | blended after mixing beforehand. Furthermore, you may mix | blend, changing the composition of a monomer mixture.

(Vi. Chain transfer agent, etc.)
After preparing the above wax fine particles, the liquid medium includes, in addition to the polymerization initiator and the polymerizable monomer, a chain transfer agent, a pH adjuster, a polymerization degree adjuster, and an antifoaming agent as necessary. Additives such as protective colloids and internal additives. Any of these additives can be used as long as the effects of the present invention are not significantly impaired. Moreover, these additives may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

Any known chain transfer agent can be used. Specific examples include t-dodecyl mercaptan, 2-mercaptoethanol, diisopropylxanthogen, carbon tetrachloride, trichlorobromomethane and the like. Moreover, a chain transfer agent is normally used in the ratio of 5 mass parts or less with respect to 100 mass parts of polymerizable monomers.
Further, any known colloid that can be used for this purpose can be used. Specific examples include partially or completely saponified polyvinyl alcohols such as polyvinyl alcohol, cellulose derivatives such as hydroxyethyl cellulose, and the like.
Examples of the internal additive include those for modifying the adhesiveness, cohesiveness, fluidity, chargeability, surface resistance and the like of toners such as silicone oil, silicone varnish, and fluorine oil.

(Vii. Polymer primary particles)
Polymer initiators, polymerizable monomers, and additives as necessary are mixed in a liquid medium containing wax fine particles, stirred, and polymerized to obtain polymer primary particles. The polymer primary particles can be obtained in the form of an emulsion in a liquid medium.

There is no restriction | limiting in the order which mixes a polymerization initiator, a polymerizable monomer, an additive, etc. with a liquid medium. Further, there are no restrictions on the method of mixing and stirring, and the method is arbitrary.
Furthermore, the reaction temperature of the polymerization (emulsion polymerization reaction) is arbitrary as long as the reaction proceeds. However, the polymerization temperature is usually 50 ° C. or higher, preferably 60 ° C. or higher, more preferably 70 ° C. or higher, and usually 120 ° C. or lower, preferably 100 ° C. or lower, more preferably 90 ° C. or lower.

  The volume average particle diameter of the polymer primary particles is not particularly limited, but is usually 0.02 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, and usually 3 μm or less, preferably 2 μm or less, more preferably Is 1 μm or less. If the volume average particle size is too small, it may be difficult to control the aggregation rate. If the volume average particle size is too large, the particle size of the toner obtained by aggregation tends to be large, and the target particles It may be difficult to obtain a toner having a diameter. The volume average particle diameter can be measured with a particle size analyzer using a dynamic light scattering method described later.

  In the present invention, the volume particle size distribution is measured by a dynamic light scattering method. This method obtains the particle size distribution by detecting the speed of Brownian motion of finely dispersed particles, irradiating the particles with laser light, and detecting light scattering (Doppler shift) with different phases according to the speed. It is. In the actual measurement, the above volume particle size is set as follows using an ultrafine particle size distribution measuring apparatus using a dynamic light scattering method (manufactured by Nikkiso Co., Ltd., UPA-EX150, hereinafter abbreviated as UPA-EX). To do.

Measurement upper limit: 6.54 μm
Measurement lower limit: 0.0008 μm
Number of channels: 52
Measurement time: 100 sec.
Measurement temperature: 25 ° C
Particle permeability: Absorption Particle refractive index: N / A (not applicable)
Particle shape: non-spherical density: 1 g / cm ³
Dispersion medium type: WATER
Dispersion medium refractive index: 1.333
At the time of measurement, measurement is performed with a sample in which a dispersion of particles is diluted with a liquid medium so that the sample concentration index is in the range of 0.01 to 0.1 and is dispersed with an ultrasonic cleaner. The volume average particle diameter according to the present invention is measured by using the result of the volume particle size distribution as an arithmetic average value.

  The polymer constituting the polymer primary particles has at least one of peak molecular weights in gel permeation chromatography, usually 3000 or more, preferably 10,000 or more, more preferably 30,000 or more, and usually 100,000 or less. , Preferably it is 70,000 or less, more preferably 60,000 or less. When the peak molecular weight is in the above range, the durability, storage stability, and fixability of the toner tend to be good. Here, as the peak molecular weight, a value converted to polystyrene is used, and components insoluble in a solvent are excluded in measurement. The peak molecular weight can be measured in the same manner as the toner described later.

  In particular, when the polymer is a styrene resin, the lower limit of the number average molecular weight of the polymer in gel permeation chromatography is usually 2000 or more, preferably 2500 or more, more preferably 3000 or more, and the upper limit is Usually, it is 50,000 or less, preferably 40,000 or less, more preferably 35,000 or less. Furthermore, the lower limit of the mass average molecular weight of the polymer is usually 20,000 or more, preferably 30,000 or more, more preferably 50,000 or more, and the upper limit is usually 1,000,000 or less, preferably 500,000 or less. When a styrene resin in which at least one of the number average molecular weight and the mass average molecular weight, preferably both are within the above ranges, is used as the polymer, the resulting toner has good durability, storage stability and fixability. is there. Further, the molecular weight distribution may have two main peaks. In addition, styrene resin refers to what styrene occupies normally 50 mass% or more in the whole polymer, Preferably 65 mass% or more is occupied.

  Further, the softening point of the polymer (hereinafter sometimes abbreviated as “Sp”) is usually 150 ° C. or less, preferably 140 ° C. or less from the viewpoint of low energy fixing, and usually 80 ° C. or more. Preferably it is 100 degreeC or more from the point of high temperature offset resistance and durability. Here, the softening point of the polymer is determined by measuring 1.0 g of a sample in a flow tester under conditions of a nozzle 1 mm × 10 mm, a load 30 kg, a preheating time of 50 ° C. for 5 minutes, and a heating rate of 3 ° C./min. The temperature at the midpoint of the strand from the start to the end of the flow can be obtained.

Furthermore, the glass transition temperature [Tg] of the polymer is usually 80 ° C. or lower, preferably 70 ° C. or lower. If the glass transition temperature [Tg] of the polymer is too high, there is a possibility that low energy fixing cannot be performed. The lower limit of the glass transition temperature [Tg] of the polymer is usually 40 ° C. or higher, preferably 50 ° C. or higher. If the glass transition temperature [Tg] of the polymer is too low, the blocking resistance may be lowered. Here, the glass transition temperature [Tg] of the polymer is the intersection of the two tangent lines by drawing a tangent line at the start of the transition (inflection) of the curve measured at a heating rate of 10 ° C./min in a differential scanning calorimeter. It can be calculated as the temperature.
The softening point and glass transition temperature [Tg] of the polymer can be adjusted to the above ranges by adjusting the kind of the polymer, the monomer composition ratio, the molecular weight, and the like.

<Mixing process and aggregation process>
By mixing and aggregating pigment particles in the emulsion in which the polymer primary particles are dispersed, an emulsion of aggregates (aggregated particles) containing a polymer and a pigment is obtained. In this case, it is preferable to prepare a pigment particle dispersion in which the pigment is uniformly dispersed in advance in a liquid medium using a surfactant or the like, and mix this with an emulsion of polymer primary particles. At this time, an aqueous solvent such as water is usually used as the liquid medium of the pigment particle dispersion, and the pigment particle dispersion is prepared as an aqueous dispersion. At that time, if necessary, a wax, a charge control agent, a release agent, an internal additive and the like may be mixed into the emulsion. Moreover, in order to maintain the stability of the pigment particle dispersion, the above-described emulsifier may be added.

As the polymer primary particles, the polymer primary particles obtained by emulsion polymerization can be used. At this time, the polymer primary particles may be used alone or in combination of two or more in any combination and ratio. Furthermore, polymer primary particles (hereinafter, referred to as “combined polymer particles” as appropriate) produced with raw materials and reaction conditions different from those of the emulsion polymerization described above may be used in combination.
Examples of the combined polymer particles include fine particles obtained by suspension polymerization or pulverization. Resin can be used as the material for such combined polymer particles. As this resin, for example, vinyl acetate, vinyl chloride, vinyl, in addition to the monomer (co) polymer used for the emulsion polymerization described above. Thermoplastics such as homopolymers or copolymers of vinyl monomers such as alcohol, vinyl butyral, vinyl pyrrolidone, saturated polyester resins, polycarbonate resins, polyamide resins, polyolefin resins, polyarylate resins, polysulfone resins, polyphenylene ether resins Examples thereof include thermosetting resins such as resins and unsaturated polyester resins, phenol resins, epoxy resins, urethane resins, and rosin-modified maleic resins. These combined polymer particles may be used alone or in combination of two or more in any combination and ratio. However, the ratio of the combination polymer particles is usually 5% by mass or less, preferably 4% by mass or less, more preferably 3% by mass or less, based on the total of the polymer primary particles and the polymer of the combination polymer particles. .

Moreover, there is no restriction | limiting in a pigment, According to the use, arbitrary things can be used. However, although the pigment is usually present in the form of particles as colorant particles, it is preferable that the pigment particles have a smaller density difference from the polymer primary particles in the emulsion polymerization aggregation method. This is because when the density difference is smaller, a uniform aggregated state is obtained when the polymer temporary particles and the pigment are aggregated, and thus the performance of the obtained toner is improved. The density of the polymer primary particles is usually 1.1 to 1.3 g / cm ³ .

From the above viewpoint, the true density of the pigment particles measured by the pycnometer method specified in JIS K 5101-11-1: 2004 is usually 1.2 g / cm ³ or more, preferably 1.3 g / cm ³ or more. Also, it is usually less than 2.0 g / cm ³ , preferably 1.9 g / cm ³ or less, more preferably 1.8 g / cm ³ or less. When the true density of the pigment is too large , the sedimentation property in a liquid medium tends to deteriorate. In addition, considering issues such as storage stability and sublimation, the pigment is preferably carbon black or an organic pigment.

Examples of pigments that satisfy the above conditions include yellow pigments, magenta pigments, and cyan pigments shown below. Further, as the black pigment, carbon black or a mixture of the following yellow pigment / magenta pigment / cyan pigment mixed with black is used.
Among these, carbon black used as a black pigment exists as an aggregate of very fine primary particles, and when dispersed as a pigment particle dispersion, the carbon black particles are likely to become coarse due to reaggregation. . The degree of reagglomeration of carbon black particles is correlated with the amount of impurities contained in carbon black (the degree of residual undecomposed organic matter). Show the trend.

For quantitative evaluation of the amount of impurities, the ultraviolet absorbance of the toluene extract of carbon black measured by the following measurement method is usually 0.05 or less, preferably 0.03 or less. In general, the carbon black of the channel method tends to have a large amount of impurities, so that the carbon black used in the toner is preferably manufactured by the furnace method.
The ultraviolet absorbance (λc) of carbon black is determined by the following method. That is, first, 3 g of carbon black was sufficiently dispersed and mixed in 30 mL of toluene. Filter using 5C filter paper. Thereafter, the filtrate was put in a quartz cell having a 1 cm square light absorption part, and the value (λs) measured for absorbance at a wavelength of 336 nm using a commercially available ultraviolet spectrophotometer, and the value obtained by measuring the absorbance of toluene alone as a reference using the same method. From (λo), the ultraviolet absorbance is obtained by λc = λs−λo. Examples of commercially available spectrophotometers include an ultraviolet-visible spectrophotometer (UV-3100PC) manufactured by Shimadzu Corporation.

As yellow pigments, for example, compounds typified by condensed azo compounds and isoindolinone compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 168, 180, 185 and the like are preferably used.
Further, examples of magenta pigments include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 166, 169, 177, 184, 185, 202, 206, 207, 209, 220, 221, 238, 254, C.I. I. Pigment Violet 19 or the like is preferably used.

  Among them, C.I. I. Pigment red 122, 202, 207, 209, C.I. I. A quinacridone pigment represented by pigment violet 19 is particularly preferred. This quinacridone pigment is suitable as a magenta pigment because of its clear hue and high light resistance. Among the quinacridone pigments, C.I. I. A compound represented by CI Pigment Red 122 is particularly preferable.

Examples of cyan pigments that can be used include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 and the like can be used particularly preferably.
In addition, 1 type may be used for a pigment and it may use 2 or more types together by arbitrary combinations and a ratio.

  The above-mentioned pigment is dispersed in a liquid medium and mixed with an emulsion containing polymer primary particles after forming a pigment particle dispersion. Under the present circumstances, the usage-amount of the pigment particle in a pigment particle dispersion is 3 mass parts or more normally with respect to 100 mass parts of liquid media, Preferably it is 5 mass parts or more, Moreover, normally 50 mass parts or less, Preferably it is 40 masses. Or less. When the blending amount of the colorant exceeds the above range, the pigment concentration is high, so the probability that the pigment particles are re-aggregated during the dispersion is increased. When the blending amount is less than the above range, the dispersion is excessive and an appropriate particle size distribution is obtained. Can be difficult.

Moreover, the ratio of the usage-amount of the pigment with respect to the polymer contained in a polymer primary particle is 1 mass% or more normally, Preferably it is 3 mass% or more, and is 20 mass% or less normally, Preferably it is 15 mass% or less. If the amount of the pigment used is too small, the image density may become thin, and if it is too large, the aggregation control may be difficult.
Further, the pigment particle dispersion may contain a surfactant. Although there is no restriction | limiting in particular in this surfactant, For example, the thing similar to the surfactant illustrated as an emulsifier in description of an emulsion polymerization method is mentioned. Of these, nonionic surfactants, anionic surfactants such as alkylaryl sulfonates such as sodium dodecylbenzenesulfonate, and polymer surfactants are preferably used. Moreover, 1 type of surfactant may be used in this case, and 2 or more types may be used together by arbitrary combinations and a ratio.

In addition, the ratio of the pigment to a pigment particle dispersion is 10-50 mass% normally.
Further, as the liquid medium of the pigment particle dispersion, an aqueous medium is usually used, and preferably water is used. At this time, the water quality of the polymer primary particles and the pigment particle dispersion is also related to the coarsening due to reaggregation of each particle, and when the conductivity is high, the dispersion stability with time tends to deteriorate. Therefore, it is preferable to use ion-exchanged water or distilled water that has been desalted so that the electrical conductivity is usually 10 μS / cm or less, preferably 5 μS / cm or less. The conductivity is measured by a conductivity meter (personal SC meter model SC72 and detector SC72SN-11 manufactured by Yokogawa Electric Corporation).
Is measured at 25 ° C.

Moreover, when mixing a pigment with the emulsion containing a polymer primary particle, you may mix a wax with an emulsion. As the wax, the same waxes described in the explanation of the emulsion polymerization method can be used. The wax may be mixed before, during or after mixing the pigment with the emulsion containing the polymer primary particles.
Moreover, when mixing a pigment with the emulsion containing a polymer primary particle, you may mix a charge control agent with an emulsion.

  As the charge control agent, any known charge control agent can be used. Examples of the positively chargeable charge control agent include nigrosine dyes, quaternary ammonium salts, triphenylmethane compounds, imidazole compounds, polyamine resins, and the like. Examples of negative charge control agents include azo complex compound dyes containing atoms such as Cr, Co, Al, Fe, and B; metal salts or metal complexes of salicylic acid or alkylsalicylic acid; curixarene compounds, benzyl Examples include metal salts or metal complexes of acids, amide compounds, phenol compounds, naphthol compounds, and phenol amide compounds. Among these, colorless or light-colored ones are preferably selected in order to avoid color tone problems as toners, and quaternary ammonium salts and imidazole compounds are particularly preferable as positively chargeable charge control agents, and negatively chargeable charge control agents. As these, alkyl salicylic acid complex compounds and curixarene compounds containing atoms such as Cr, Co, Al, Fe and B are preferred. In addition, 1 type may be used for a charge control agent and it may use 2 or more types together by arbitrary combinations and a ratio.

Although there is no restriction | limiting in the usage-amount of a charge control agent, 0.01 mass part or more normally with respect to 100 mass parts of polymers, Preferably it is 0.1 mass part or more, Moreover, 10 mass parts or less, Preferably it is 5 mass parts or less. It is. If the amount of the charge control agent used is too small or too large, the desired charge amount may not be obtained.
The charge control agent may be mixed before, during or after mixing the pigment with the emulsion containing the polymer primary particles.

Moreover, it is desirable that the charge control agent is mixed at the time of aggregation in the state of being emulsified in a liquid medium (usually an aqueous medium) in the same manner as the pigment particles.
After the pigment is mixed in the emulsion containing the polymer primary particles, the polymer primary particles and the pigment are aggregated. As described above, at the time of mixing, the pigment is usually mixed in the state of a pigment particle dispersion.

The aggregation method is not limited and is arbitrary, and examples thereof include heating, electrolyte mixing, pH adjustment, and the like. Among these, a method of mixing an electrolyte is preferable.
Examples of the electrolyte when the aggregation is performed by mixing the electrolyte include chlorides such as NaCl, KCl, LiCl, MgCl ₂ , and CaCl ₂ ; Na ₂ SO ₄ , K ₂ SO ₄ , Li ₂ SO ₄ , MgSO ₄ , Examples include inorganic salts such as sulfates such as CaSO ₄ , ZnSO ₄ , Al ₂ (SO ₄ ) ₃ , and Fe ₂ (SO ₄ ) ₃ ; organic salts such as CH ₃ COONa and C ₆ H ₅ SO ₃ Na. Of these, inorganic salts having a divalent or higher polyvalent metal cation are preferred.

In addition, 1 type may be used for electrolyte and it may use 2 or more types together by arbitrary combinations and a ratio.
The amount of electrolyte used varies depending on the type of electrolyte, but is usually 0.05 parts by mass or more, preferably 0.1 parts by mass or more, and usually 25 parts by mass or less, based on 100 parts by mass of the solid component in the emulsion. Preferably it is 15 mass parts or less, More preferably, it is 10 mass parts or less. In the case of agglomerating by mixing electrolytes, if the amount of electrolyte used is too small, the progress of the agglutination reaction slows down, and fine particles of 1 μm or less remain after the agglomeration reaction, or the average particle size of the obtained aggregate is the target There is a possibility that the particle size will not be reached, and if the amount of electrolyte used is too large, the agglomeration reaction will occur rapidly, making it difficult to control the particle size. May be included.

The obtained agglomerates are preferably subsequently spheroidized by heating in a liquid medium, similarly to the secondary agglomerates (agglomerates that have undergone the melting step) described later. Heating may be performed under the same conditions as in the case of the secondary aggregate (same conditions as described in the description of the fusion process).
On the other hand, when the aggregation is performed by heating, the temperature condition is arbitrary as long as the aggregation proceeds. Specific temperature conditions are usually 15 ° C. or higher, preferably 20 ° C. or higher, and aggregation is performed under a temperature condition of a polymer primary particle polymer glass transition temperature [Tg] or lower, preferably 55 ° C. or lower. . Although the time for agglomeration is also arbitrary, it is usually 10 minutes or longer, preferably 60 minutes or longer, and usually 300 minutes or shorter, preferably 180 minutes or shorter.

Moreover, it is preferable to stir when aggregating. Although the apparatus used for stirring is not specifically limited, What has a double helical blade is preferable.
The obtained agglomerates may proceed directly to the next step of forming a resin coating layer (encapsulation step), or may proceed to the encapsulation step after subsequent fusion treatment by heating in a liquid medium. . Desirably, after the aggregation step, the encapsulation step is performed, and the fusion step is performed by heating at a temperature equal to or higher than the glass transition temperature [Tg] of the encapsulated resin fine particles. It is preferable because it does not cause deterioration (such as heat deterioration).

<Encapsulation process>
After obtaining the aggregate, it is preferable to form a resin coating layer on the aggregate as necessary. The encapsulation process for forming a resin coating layer on the aggregate is a process for coating the aggregate with a resin by forming a resin coating layer on the surface of the aggregate. Thereby, the manufactured toner is provided with the resin coating layer. In the encapsulation process, the entire toner may not be completely covered, but the pigment makes it possible to obtain a toner that is not substantially exposed on the surface of the toner particles. Although there is no restriction | limiting in the thickness of the resin coating layer in this case, Usually, it is the range of 0.01-0.5 micrometer.

The method for forming the resin coating layer is not particularly limited, and examples thereof include a spray drying method, a mechanical particle composite method, an in-situ polymerization method, and a submerged particle coating method.
As a method for forming the resin coating layer by the spray drying method, for example, an aggregate forming an inner layer and resin fine particles forming a resin coating layer are dispersed in an aqueous medium to prepare a dispersion, A resin coating layer can be formed on the surface of the aggregate by spraying and drying.

  In addition, as a method for forming a resin coating layer by the mechanical particle composite method, for example, an aggregate that forms an inner layer and resin fine particles that form a resin coating layer are dispersed in a gas phase and mechanically formed in a narrow gap. In this method, resin fine particles are formed into a film on the surface of the aggregate by applying a strong force. For example, an apparatus such as a hybridization system (manufactured by Nara Machinery Co., Ltd.) or a mechanofusion system (manufactured by Hosokawa Micron Corporation) can be used.

Further, as the in-situ polymerization method, for example, the aggregate is dispersed in water, the monomer and the polymerization initiator are mixed, adsorbed on the surface of the aggregate, and heated to polymerize the monomer. Thus, a resin coating layer is formed on the surface of the aggregate that is the inner layer.
The submerged particle coating method includes, for example, reacting or bonding an aggregate forming an inner layer and resin fine particles forming an outer layer in an aqueous medium to form a resin coating layer on the surface of the aggregate forming the inner layer. Is a method of forming

  The resin fine particles used for forming the outer layer are particles mainly having a resin component smaller than the aggregate. The resin fine particles are not particularly limited as long as they are particles composed of a polymer. However, from the viewpoint that the thickness of the outer layer can be controlled, it is preferable to use resin fine particles similar to the polymer primary particles, the aggregates, or the fused particles obtained by fusing the aggregates. Resin fine particles similar to these polymer primary particles can be produced in the same manner as the polymer primary particles in the aggregate used for the inner layer.

The amount of resin fine particles used is arbitrary, but is usually 1% by mass or more, preferably 5% by mass or more, and usually 50% by mass or less, preferably 25% by mass or less based on the toner particles. Is desirable.
Furthermore, in order to effectively fix or fuse the resin fine particles to the aggregate, the resin fine particles usually have a particle size of about 0.04 to 1 μm.

  The glass transition temperature [Tg] of the polymer component (resin component) used in the resin coating layer is usually 60 ° C. or higher, preferably 70 ° C. or higher, and usually 110 ° C. or lower. Further, the glass transition temperature [Tg] of the polymer component used in the resin coating layer is preferably higher by 5 ° C. or higher than the glass transition temperature [Tg] of the polymer primary particles, and is higher by 10 ° C. or higher. It is more preferable. If the glass transition temperature [Tg] is too low, storage in a general environment is difficult, and if it is too high, sufficient meltability cannot be obtained.

Furthermore, it is preferable to contain polysiloxane wax in the resin coating layer. Thereby, the advantage of improvement in high temperature offset resistance can be obtained. Examples of the polysiloxane wax include silicone wax having an alkyl group.
The content of the polysiloxane wax is not limited, but is usually 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.08% by mass or more, and usually 2% by mass or less in the toner. Preferably it is 1 mass% or less, More preferably, you may be 0.5 mass% or less. If the amount of the polysiloxane wax in the resin coating layer is too small, the high temperature offset resistance may be insufficient, and if it is too large, the blocking resistance may be lowered.

  The method for containing the polysiloxane wax in the resin coating phase is arbitrary. For example, emulsion polymerization is performed using the polysiloxane wax as a seed, and the obtained resin fine particles and the aggregates forming the inner layer are mixed in an aqueous medium. And a resin coating layer containing polysiloxane wax on the surface of the agglomerate forming the inner layer.

<Fusion process>
In the fusing process, the aggregates are melt-integrated by heat-treating the aggregates.
In addition, when encapsulating resin fine particles are formed by forming a resin coating layer on the aggregate, the polymer constituting the aggregate and the resin coating layer on the surface thereof are integrated by heat treatment. It will be. Thereby, the pigment particles are obtained in a form that is not substantially exposed on the surface.

  The temperature of the heat treatment in the fusion step is set to a temperature equal to or higher than the glass transition temperature [Tg] of the polymer primary particles constituting the aggregate. Moreover, when a resin coating layer is formed, it is set as the temperature more than the glass transition temperature [Tg] of the polymer component which forms a resin coating layer. Although specific temperature conditions are arbitrary, it is preferable that it is 5 degreeC or more normally higher than the glass transition temperature [Tg] of the polymer component which forms a resin coating layer. Although there is no restriction | limiting in the upper limit, below 50 degreeC higher than the glass transition temperature [Tg] of the polymer component which forms a resin coating layer is preferable.

The heat treatment time is usually 0.5 to 6 hours, although it depends on the treatment capacity and the production amount.
<Washing and drying process>
When the above-described steps are performed in a liquid medium, the toner can be obtained by washing the encapsulated resin particles obtained after the fusing step and drying to remove the liquid medium. There are no restrictions on the washing and drying methods, and they are arbitrary.

<Physical properties relating to toner particle size>
There is no limitation on the volume average particle diameter [Dv] of the toner, and it is optional as long as the effects of the present invention are not significantly impaired. Usually, it is 4 μm or more, preferably 5 μm or more, and usually 10 μm or less, preferably 8 μm or less. If the volume average particle diameter [Dv] of the toner is too small, the stability of the image quality may be lowered, and if it is too large, the resolution may be lowered.

  The toner has a value [Dv / Dn] obtained by dividing the volume average particle diameter [Dv] by the number average particle diameter [Dn], usually 1.0 or more, and usually 1.25 or less, preferably 1.20. Below, it is desirable that it is 1.15 or less more preferably. The value of [Dv / Dn] represents the state of the particle size distribution, and the closer this value is to 1.0, the sharper the particle size distribution. A sharper particle size distribution is desirable because the chargeability of the toner becomes uniform.

  Further, the toner has a volume fraction of a particle size of 25 μm or more, usually 1% or less, preferably 0.5% or less, more preferably 0.1% or less, and still more preferably 0.05% or less. The smaller this value, the better. This means that the ratio of the coarse powder contained in the toner is small. If the coarse powder is small, the amount of toner consumed during continuous development is small and the image quality is stable. Although it is most preferable that there is no coarse powder having a particle size of 25 μm or more, it is difficult in actual production, and usually it may not be 0.005% or less.

Further, the toner has a volume fraction of 15 μm or more in particle size, usually 2% or less, preferably 1% or less, more preferably 0.1% or less. Although it is most preferable that there is no coarse powder having a particle size of 15 μm or more, it is difficult in actual production, and it is usually not necessary to make it 0.01% or less.
Further, it is desirable that the toner has a number fraction having a particle diameter of 5 μm or less, which is usually 15% or less, preferably 10% or less, in order to improve image fog.

  Here, the volume average particle diameter [Dv], the number average particle diameter [Dn], the volume fraction, the number fraction, and the like of the toner can be measured as follows. That is, as a toner particle size measuring device, a multisizer type II or type III (manufactured by Beckman Coulter, Inc.) of a Coulter counter is used, and an interface for outputting the number distribution / volume distribution and a general personal computer are connected. To use. In addition, Isoton II is used as the electrolytic solution. As a measuring method, 0.1 to 5 mL of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 mL of the electrolytic solution, and 2 to 20 mg of a measurement sample (toner) is further added. Then, the electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and measured using a multisizer type II or type III of the Coulter counter using a 100 μm aperture. Thus, the number and volume of the toner are measured to calculate the number distribution and the volume distribution, respectively, and the volume average particle diameter [Dv] and the number average particle diameter [Dn] are obtained, respectively.

<Physical properties related to the molecular weight of the toner>
At least one of the peak molecular weights in the gel permeation chromatography (hereinafter sometimes abbreviated as GPC) of the THF soluble content of the toner is usually 10,000 or more, preferably 20,000 or more, more preferably 30,000 or more. In general, it is 150,000 or less, preferably 100,000 or less, more preferably 70,000 or less. THF refers to tetrahydrofuran. When the peak molecular weight is lower than the above range, the mechanical durability in the non-magnetic one-component development method may be deteriorated. When the peak molecular weight is higher than the above range, the low temperature fixability and the fixing strength are deteriorated. There is a case.

Further, the THF-insoluble content of the toner is usually 10% or more, preferably 20% or more, and usually 60% or less, preferably 50% or less, when measured by a mass method by Celite filtration described later. If it is not within the above range, it may be difficult to achieve both mechanical durability and low-temperature fixability.
The peak molecular weight of the toner is measured under the following conditions using a measuring apparatus: HLC-8120GPC (manufactured by Tosoh Corporation).

That is, the column is stabilized in a heat chamber at 40 ° C., and tetrahydrofuran (THF) as a solvent is allowed to flow through the column at this temperature at a flow rate of 1 mL (milliliter) per minute. Next, the toner is dissolved in THF and filtered through a 0.2 μm filter, and the filtrate is used as a sample.
The measurement is performed by injecting 50 to 200 μL of a THF solution of a resin whose sample concentration (resin concentration) is adjusted to 0.05 to 0.6 mass%. In measuring the molecular weight of the sample (resin component in the toner), the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of the calibration curve created by several monodisperse polystyrene standard samples and the number of counts. As a standard polystyrene sample for preparing a calibration curve, for example, Pressure Chemical Co. Manufactured by Toyo Soda Kogyo Co., Ltd., with molecular weights of 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , It is appropriate to use 3.9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ , and use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.

Furthermore, as a column used in the measurement method, in order to accurately measure a molecular weight region of 10 ³ to 2 × 10 ⁶ , it is preferable to combine a plurality of commercially available polystyrene gel columns, for example, manufactured by Waters A combination of μ-styrel 500, 103, 104, 105 and a combination of shodex KA801, 802, 803, 804, 805, 806, 807 manufactured by Showa Denko KK are preferable.

The measurement of the insoluble content of tetrahydrofuran (THF) in the toner can be performed as follows. That is, 1 g of a sample (toner) was added to 100 g of THF, and allowed to stand still at 25 ° C. for 24 hours. After filtration using 10 g of Celite, the solvent of the filtrate was distilled off to determine the THF-soluble matter, and subtracted from 1 g. Insoluble matter can be calculated.
<Softening point and glass transition temperature of toner>
There is no limitation on the softening point [Sp] of the toner, and it is optional as long as the effects of the present invention are not significantly impaired. From the viewpoint of fixing with low energy, it is usually 150 ° C. or lower, preferably 140 ° C. or lower. Further, from the viewpoint of high temperature offset resistance and durability, the softening point is usually 80 ° C. or higher, preferably 100 ° C. or higher.

The toner softening point [Sp] was measured with a flow tester under the conditions of 1.0 g of a sample of 1 mm × 10 mm nozzle, a load of 30 kg, a preheating time of 50 ° C. for 5 minutes, and a heating rate of 3 ° C./min. The temperature at the midpoint of the strand from the start to the end of the flow can be obtained.
Further, there is no limitation on the glass transition temperature [Tg] of the toner, and it is arbitrary as long as the effects of the present invention are not significantly impaired. . The glass transition temperature [Tg] is usually 40 ° C. or higher, preferably 50 ° C. or higher, from the viewpoint of blocking resistance.

The glass transition temperature [Tg] of the toner is obtained by drawing a tangent line at the start of the transition (inflection) of the curve measured with a differential scanning calorimeter at a temperature rising rate of 10 ° C./min. It can be determined as temperature.
The softening point [Sp] and glass transition temperature [Tg] of the toner are greatly influenced by the type and composition ratio of the polymer contained in the toner. Therefore, the softening point [Sp] and the glass transition temperature [Tg] of the toner can be adjusted by appropriately optimizing the type and composition of the polymer. It can also be adjusted by the molecular weight of the polymer, the gel content, the type of low melting point components such as wax, and the blending amount.

<Wax in toner>
When the toner contains wax, the dispersed particle diameter of the wax in the toner particles is usually 0.1 μm or more, preferably 0.3 μm or more as an average particle diameter, and the upper limit is usually 3 μm or less, preferably 1 μm. It is as follows. If the dispersed particle size is too small, the effect of improving the filming resistance of the toner may not be obtained. If the dispersed particle size is too large, the wax will be easily exposed on the surface of the toner, and the chargeability and heat resistance will be reduced. May be reduced.

The dispersed particle diameter of the wax may be determined by observing an electron microscope after slicing the toner, or wax particles remaining on the filter after elution of the toner polymer with an organic solvent or the like in which the wax does not dissolve. Can be confirmed by a method of measuring with a microscope.
Further, the proportion of the wax in the toner is arbitrary as long as the effects of the present invention are not significantly impaired, but usually 0.05% by mass or more, preferably 0.1% by mass or more, more preferably 1% by mass or more, Further preferably, it is 4% by mass or more, usually 20% by mass or less, preferably 15% by mass or less. If the amount of wax is too small, the fixing temperature range may be insufficient. If the amount is too large, the apparatus member may be contaminated and the image quality may deteriorate.

<Externally added fine particles>
In order to improve toner fluidity, charging stability, anti-blocking property at high temperatures, and the like, external additive fine particles may be added to the surface of the toner particles.
As a method for attaching the externally added fine particles to the toner particle surface, for example, in the above-described toner manufacturing method, the secondary aggregate and the externally added fine particles are mixed in a liquid medium and then heated to externally add the toner particles onto the toner particles. Examples include a method of fixing fine particles; a method of mixing or fixing externally added fine particles to toner particles obtained by separating, washing, and drying secondary aggregates from a liquid medium.

  Examples of the mixer used when the toner particles and the externally added fine particles are mixed in a dry type include a Henschel mixer, a super mixer, a nauter mixer, a V-type mixer, a Redige mixer, a double cone mixer, and a drum type mixer. Can be mentioned. In particular, it is preferable to use a high-speed agitation type mixer such as a Henschel mixer or a super mixer, and appropriately mix the mixture by stirring and mixing uniformly by appropriately setting the blade shape, the number of revolutions, the time, the number of times of driving and stopping, and the like.

In addition, as a device used for fixing toner particles and externally added fine particles in a dry method, a compression shearing device capable of applying compressive shear stress, a particle surface melting processing device capable of melting the particle surface, etc. Is mentioned.
A compression shearing apparatus generally has a narrow gap portion composed of a head surface and a head surface, a head surface and a wall surface, or a wall surface and a wall surface that move relatively while maintaining a gap, and particles to be processed are disposed in the gap. By being forced to pass through the portion, compressive stress and shear stress are applied to the particle surface without substantial pulverization. An example of such a compression shearing apparatus is a mechanofusion apparatus manufactured by Hosokawa Micron.

On the other hand, the particle surface melting treatment apparatus is generally configured so as to fix the externally added fine particles by using a hot air stream or the like and instantaneously heating the mixture of the basic fine particles and the externally added fine particles to a temperature higher than the melting start temperature of the basic fine particles. The Examples of such a particle surface melting apparatus include a surfing system manufactured by Nippon Pneumatic Co., Ltd.
As the externally added fine particles, known fine particles that can be used for this purpose can be used. Examples thereof include inorganic fine particles and organic fine particles.

  Examples of the inorganic fine particles include silicon carbide, boron carbide, titanium carbide, zirconium carbide, hafnium carbide, vanadium carbide, tantalum carbide, niobium carbide, tungsten carbide, chromium carbide, molybdenum carbide, calcium carbide and the like, boron nitride, nitriding Nitride such as titanium, zirconium nitride, silicon nitride, boride such as zirconium boride, silica, colloidal silica, titanium oxide, aluminum oxide, calcium oxide, magnesium oxide, zinc oxide, copper oxide, zirconium oxide, cerium oxide, talc , Oxides and hydroxides such as hydrotalcite, various titanate compounds such as calcium titanate, magnesium titanate, strontium titanate, barium titanate, tricalcium phosphate, calcium dihydrogen phosphate, monohydrogen phosphate calcium Phosphoric compounds such as substituted calcium phosphates in which a portion of the phosphate ions is replaced by anions, sulfides such as molybdenum disulfide, fluorides such as magnesium fluoride and fluorocarbon, aluminum stearate, calcium stearate, stearic acid Various carbon blacks including metal soaps such as zinc and magnesium stearate, talc, bentonite, and conductive carbon black can be used. Furthermore, magnetic substances such as magnetite, maghematite, and an intermediate between magnetite and maghematite may be used.

On the other hand, as the organic fine particles, for example, styrene resin, acrylic resin such as polymethyl acrylate and polymethyl methacrylate, epoxy resin, melamine resin, tetrafluoroethylene resin, trifluoroethylene resin, polyvinyl chloride, Fine particles such as polyethylene and polyacrylonitrile can be used.
Among these externally added fine particles, silica, titanium oxide, alumina, zinc oxide, carbon black and the like are particularly preferably used.

In addition, 1 type may be used for an external addition fine particle, and 2 or more types may be used together by arbitrary combinations and a ratio.
In addition, the surface of these inorganic or organic fine particles may be a silane coupling agent, titanate coupling agent, silicone oil, modified silicone oil, silicone varnish, fluorine silane coupling agent, fluorine silicone oil, amino group or fourth group. Surface treatment such as hydrophobization may be performed by a treatment agent such as a coupling agent having a secondary ammonium base. In addition, 1 type may be used for a processing agent and it may use 2 or more types together by arbitrary combinations and a ratio.

  Further, the number average particle diameter of the externally added fine particles is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.001 μm or more, preferably 0.005 μm or more, and usually 3 μm or less, preferably 1 μm or less. A plurality of those having different average particle diameters may be blended. The average particle diameter of the externally added fine particles can be determined by observation with an electron microscope, conversion from the value of the BET specific surface area, or the like.

The ratio of the externally added fine particles to the toner is arbitrary as long as the effects of the present invention are not significantly impaired. However, the ratio of the externally added fine particles to the total mass of the toner and the externally added fine particles is usually 0.1% by mass or more, preferably 0.3% by mass or more, more preferably 0.5% by mass or more, and usually 10%. Desirably, it is not more than mass%, preferably not more than 6 mass%, more preferably not more than 4 mass%. If the amount of the externally added fine particles is too small, the fluidity and the charging stability may be insufficient, and if the amount is too large, the fixability may be deteriorated.

<Toner and others>
The charging characteristics of the toner may be negatively charged or positively charged, and can be set according to the method of the image forming apparatus used. The charging characteristics of the toner can be adjusted by the selection and composition ratio of toner base particle components such as a charge control agent, the selection and composition ratio of externally added fine particles, and the like.

The toner can be used as a one-component developer or can be mixed with a carrier and used as a two-component developer.
When used as a two-component developer, examples of the carrier that forms a developer by mixing with toner include magnetic substances such as known iron powder, ferrite, and magnetite carriers, or resins on the surface thereof. A coated one or a magnetic resin carrier can be used.

As the carrier coating resin, for example, generally known styrene resins, acrylic resins, styrene acrylic copolymer resins, silicone resins, modified silicone resins, fluorine resins, and the like can be used. Is not to be done.
The average particle diameter of the carrier is not particularly limited, but those having an average particle diameter of 10 to 200 μm are preferable. These carriers are preferably used at a ratio of 5 to 100 parts by mass with respect to 1 part by mass of the toner.
The formation of a full color image by electrophotography can be carried out by a conventional method using magenta, cyan and yellow color toners and, if necessary, black toner.

<Cartridge, image forming apparatus>
Next, a drum cartridge and an image forming apparatus using the electrophotographic photosensitive member of the present invention will be described with reference to FIG.
In FIG. 1, reference numeral 1 denotes a drum-shaped photoconductor, which is driven to rotate about a shaft 2 in the direction of an arrow at a predetermined peripheral speed. The photosensitive member 1 is uniformly charged with a predetermined positive or negative potential on the surface by the charging unit 3 during the rotation process, and then exposure for forming a latent image is performed by the image exposure unit in the exposure unit 4. The formed electrostatic latent image is then developed with toner by the developing means 5, and the toner developed image is sequentially transferred to a transfer body (paper or the like) 7 fed from the paper feeding unit by the corona transfer means 6. . The image-transferred transfer body is then sent to the fixing unit 8 where the image is fixed and printed out of the apparatus. The surface of the photoconductor 1 after the image transfer is cleaned by the cleaning unit 9 to remove the transfer residual toner, and is neutralized by the neutralizing unit 10 for the next image formation.

  In using the electrophotographic photoreceptor of the present invention, as a charger, in addition to a corona charger such as corotron and scorotron shown in FIG. 1, a directly charged member to which voltage is applied is brought into contact with the surface of the photoreceptor. Direct charging means for charging may be used. Examples of the direct charging means include a contact charger such as a charging roller and a charging brush. As the direct charging means, any one that involves air discharge or injection charging that does not involve air discharge is possible. In addition, as a voltage applied at the time of charging, in the case of only a direct current voltage, an alternating current can be superimposed on a direct current.

For the exposure, a halogen lamp, a fluorescent lamp, a laser (semiconductor, He—Ne), LED, a photoreceptor internal exposure system, or the like is used. As the digital electrophotographic system, it is preferable to use a laser, LED, optical shutter array, or the like. . As the wavelength, in addition to 780 nm monochromatic light, it is possible to use monochromatic light in the 600 to 700 nm region and slightly shorter wavelength.
In the development process, a dry development method such as cascade development, one-component insulating toner development, one-component conductive toner development, two-component magnetic brush development, or the like is used. As the toner, in addition to the pulverized toner, chemical toners such as suspension granulation, suspension polymerization, and emulsion polymerization aggregation can be used. In particular, in the case of chemical toners, those having a small particle diameter of about 4 to 8 μm are used, and those having a shape close to a sphere, and those outside the potato-like sphere can also be used. The polymerized toner is excellent in charging uniformity and transferability, and is preferably used for high image quality.

For the transfer process, electrostatic transfer methods such as corona transfer, roller transfer, and belt transfer, pressure transfer methods, and adhesive transfer methods are used. For fixing, heat roller fixing, flash fixing, oven fixing, pressure fixing, IH fixing, belt fixing, IHF fixing, etc. are used. These fixing methods may be used alone or in combination with a plurality of fixing methods. May be.
For cleaning, brush cleaner, magnetic brush cleaner, electrostatic brush cleaner, magnetic roller cleaner, blade cleaner, etc. are used.

In many cases, the static elimination step is omitted, but when used, a fluorescent lamp, LED, or the like is used, and an exposure energy that is three times or more of the exposure light is often used as the intensity.
In addition to these processes, a pre-exposure process and an auxiliary charging process may be included.
In the present invention, a plurality of components such as the drum-shaped photosensitive member 1, the charging unit 3, the developing unit 5, and the cleaning unit 9 are integrally coupled as a drum cartridge, and the drum cartridge is copied. It may be configured to be detachable from the main body of an electrophotographic apparatus such as a machine or a laser beam printer. For example, at least one of the charging unit 3, the developing unit 5, and the cleaning unit 9 can be integrally supported together with the drum-shaped photoreceptor 1 to form a cartridge.

Hereinafter, the present invention will be described in more detail with reference to production examples, examples and comparative examples. In addition, the following examples are shown in order to explain the present invention in detail, and the present invention is not limited to the following examples unless it is contrary to the gist thereof.
<Photosensitive sheet preparation method>
10 parts by mass of the phthalocyanine compound was added to 150 parts by mass of 4-methoxy-4-methyl-2-pentanone, and pulverized and dispersed in a sand grind mill for 1 hour. Further, 5 parts by weight of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: Denka Butyral # 6000C) 5 wt% 1,2-dimethoxyethane solution and 5 parts by weight of phenoxy resin (Union Carbide, trade name PKHH) 1, A binder solution was prepared by mixing 100 parts of a 2-dimethoxyethane solution. 100 parts by mass of the binder solution and 1,2-dimethoxyethane were added to 160 parts by mass of the pigment dispersion prepared previously to finally prepare a coating solution for a charge generation layer having a solid content concentration of 4.0%.

The dispersion thus obtained was applied onto a 75 μm thick polyethylene terephthalate film having aluminum deposited on the surface so that the film thickness after drying was 0.3 μm, thereby providing a charge generation layer.
Next, on this film, 100 parts by mass of the binder resin, L part by mass of the first charge transport material, M part by mass of the second charge transport material, and 0.05 part by mass of silicone oil using a leveling agent were added to tetrahydrofuran / toluene. A charge transport layer coating solution was prepared by dissolving in 640 parts by mass of a mixed solvent (mixing ratio 80:20). The prepared charge transport layer coating solution is applied onto the charge generation layer provided earlier, dried at 125 ° C. for 20 minutes, provided with a charge transport layer so that the film thickness after drying is 25 μm, and an electrophotographic photosensitive member is obtained. Obtained.

  Table 3 shows values of HOMO energy levels E_homo and polarizability αcal of HTM1 to HTM5.

  Electrophotographic photosensitive members (SE1 to SE10 and SP1 to SP12) were prepared according to the above <Photosensitive member sheet preparation method>. Table 4 shows the combinations of the binder resin, the charge transporting material, and their added parts by mass used for each electrophotographic photosensitive member.

<Evaluation of electrical characteristics of photoconductor>
Using an electrophotographic characteristic evaluation apparatus (basic and applied electrophotographic technology, edited by the Electrophotographic Society, Corona, pages 404-405) prepared according to the Electrophotographic Society measurement standard, the photoconductor is made into an aluminum drum. Attached to a cylindrical shape, the aluminum drum and the aluminum base of the photoconductor are connected, and then the drum is rotated at a constant rotational speed, and an electrical property evaluation test is performed by a cycle of charging, exposure, potential measurement, and static elimination. went.

At that time, the initial surface potential was −700 V, exposure was 780 nm, and charge removal was monochromatic light of 660 nm. As the surface potential (VL) when 780 nm light was irradiated at 1.0 μJ / cm ² and the index representing sensitivity, the exposure amount (half exposure amount) required to halve the surface potential to −350 V was measured. In the VL measurement, the time required for the exposure-potential measurement was 100 ms. The measurement environment was a temperature of 25 ° C. and a relative humidity of 50%. It shows that an electrical property is so favorable that the absolute value of a sensitivity (half exposure amount) and the value of VL is small. The results of electrical characteristics are shown in Table-5.

As a result of the above, when the electric characteristics of Comparative Example 4, Comparative Example 5 and Comparative Example 6 using the second charge transport material outside the range of the parameters of the present invention were compared with other examples, VL was all high and In Example 5, it can be seen that the sensitivity is also poor. Photosensitive drums were prepared according to the following <Photosensitive drum preparation method> with respect to the photosensitive compositions except for Comparative Example 4, Comparative Example 5 and Comparative Example 6 in Table-4.
<Photosensitive drum creation method>
The surface of an aluminum cylinder having a mirror-finished outer diameter of 30 mm, length of 376 mm, and wall thickness of 0.75 mm is anodized and then sealed with a sealant mainly composed of nickel acetate. By performing, an anodic oxide film (alumite film) of about 6 μm was formed. The charge generation used in the above <Photosensitive sheet preparation method> except that the undercoat layer forming coating solution shown below was applied onto the cylinder on which the alumite film was formed to form a 1.5 μm undercoat layer. The coating solution for the layer and the coating solution for the charge transport layer are sequentially applied onto the undercoat layer by a dip coating method, and the charge generation layer and the charge transport are so adjusted that the film thickness after drying is 0.4 μm and 18 μm, respectively. Layers were formed to produce drum-shaped electrophotographic photosensitive members (photosensitive drums DE1 to DE10 and DP1 to 9).

<Method for adjusting coating liquid for forming undercoat layer>
A rutile type titanium oxide having an average primary particle diameter of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by mass of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) with respect to the titanium oxide were added to a Henschel mixer. 1 kg of a raw slurry obtained by mixing 50 parts of surface-treated titanium oxide obtained by mixing with 120 parts of methanol, and using a zirconia bead having a diameter of about 100 μm (YTZ, manufactured by Nikkato Co., Ltd.) as a dispersion medium, a mill volume of about 0 Using a 15-liter Ultra Apex Mill (UAM-015 type) manufactured by Kotobuki Kogyo Co., Ltd., a titanium oxide dispersion was prepared by dispersing for 1 hour in a liquid circulation state with a rotor peripheral speed of 10 m / second and a liquid flow rate of 10 kg / hour. .

  The titanium oxide dispersion, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam [compound represented by the following formula (A)] / bis (4-amino-3-methylcyclohexyl) methane [the following formula Compound represented by (B)] / Hexamethylenediamine [Compound represented by the following formula (C)] / Decamethylene dicarboxylic acid [Compound represented by the following formula (D)] / Octadecamethylene dicarboxylic acid [Formula ( The compound represented by E)] was stirred and mixed with pellets of copolymerized polyamide having a composition molar ratio of 60% / 15% / 5% / 15% / 5% to dissolve the polyamide pellets. After that, ultrasonic dispersion treatment with an ultrasonic transmitter with an output of 1200 W is performed for 1 hour, and a PTFE membrane filter (adva And the mass ratio of the surface-treated titanium oxide / copolymerized polyamide is 3/1, and the mass ratio of the mixed solvent of methanol / 1-propanol / toluene is 7/1/2. Thus, a coating solution for forming an undercoat layer having a solid content concentration of 18.0% by mass was obtained.

Table-6 shows the combinations of binder resins, charge transport materials, additives, and added parts by mass used for each electrophotographic photosensitive member.
The manufactured photoconductor drum is printed on a color printer MICROLINE Pro manufactured by Oki Data.
It was mounted on a 9800PS-E black drum cartridge. Next, a developing toner (volume average particle size 7.05 μm, Dv / Dn = 1.14, average circularity 0. 10 μm) manufactured according to the manufacturing method (emulsion polymerization aggregation method) of developing toner A disclosed in Japanese Patent Application Laid-Open No. 2007-213050. 963) was mounted on a black toner cartridge. These drum cartridges and toner cartridges were mounted on the printer.

Specifications of MICROLINE Pro 9800PS-E 4 tandem color 36ppm, monochrome 40ppm
1200 dpi
Contact roller charging (DC voltage applied)
LED exposure

<Image evaluation>
For the drums (DE1 to DE10) of Examples 9 to 16 and the drums (DP1 to DP9) of Comparative Examples 11 to 17 prepared based on the above-described photosensitive drum production method, the temperature was 35 ° C. and the humidity was 80%. 10,000 sheets of images were formed in the environment. Table 7 shows the values of universal hardness, elastic deformation rate, and results of image evaluation (cleaning properties, occurrence of filming, noise, and adhesion).

The following rankings were given for poor cleaning, filming and noise.
“Cleaning failure” item ○: No image contamination due to poor cleaning.
Δ: Slight image defects due to poor cleaning can be confirmed, but practically usable.
×: Image contamination due to poor cleaning occurs on the entire surface, which is a practically problematic level.

“Filming” item ○: No filming occurred.
Δ: Slight filming can be confirmed, but at a practically usable level.
X: Filming occurs on the entire surface, and there is a practically problematic level.
“Sounding” item ○: No abnormal noise has occurred.
Δ: A level where there is no problem in practical use although slight noise is generated.
X: An abnormal sound is generated and there is a practical problem.

<Adhesion test>
On the photosensitive drum, using an NT cutter, 11 pieces were cut at intervals of 1 mm in both the circumferential direction and the axial direction to produce 10 × 10 100 squares. Cellotape (registered trademark) (manufactured by Nichiban Co., Ltd.) was affixed thereon and pulled up to 45 ° obliquely to test the adhesion of the photosensitive layer. The number of cells of the photosensitive layer remaining on the support is evaluated, and the larger the number of cells remaining, the better.

“Adhesion” item ○: Remaining mass number 90 or more Δ: Remaining mass number 89-60
X: Remaining mass number 59 or less

<Comparative Example 20>
Photosensitive drum DP10 described in Example 1 of JP2011-170041 (Patent Document 5) was prepared, and image evaluation and adhesion test were performed in the same manner as described above.
The results are shown in Table-8.

From the results of Tables 7 and 8, it can be seen that the photoreceptors (DE1 to DE10) within the parameter range of the present invention are well cleaned, do not cause filming, and do not generate sound during printing. .
Furthermore, there is no film peeling and adhesion is good. On the other hand, photoconductors (DP1 and DP2) having a low universal hardness that do not use the second charge transporting material within the parameter range of the present invention produced a sound and deteriorated adhesion. In addition, the photoreceptors (DP3, DP4, DP5, DP6, DP7, DP8 and DP9) having a low elastic deformation rate had poor cleaning properties and filming was observed.

  From the results of Table-5 and Table-7, the photoreceptor satisfying all the parameters of the present invention has good electrical characteristics, and even when image evaluation is performed, the cleaning property, the occurrence of filming, the occurrence of noise and the adhesion Good results were obtained in this aspect.

1 Photoconductor (Electrophotographic photoconductor)
2 Charging device (charging roller; charging unit)
3 Exposure equipment (exposure section)
4 Development device (development unit)
5 Transfer device 6 Cleaning device (cleaning part)
7 Fixing Device 41 Developing Tank 42 Agitator 43 Supply Roller 44 Developing Roller 45 Regulating Member 71 Upper Fixing Member (Pressure Roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper (paper, medium)

Claims (7)

In an electrophotographic photosensitive member having a photosensitive layer on a conductive support, the photosensitive layer includes a plurality of types of charge transport materials, and the density functional calculation B3LYP / 6-31G (d, The energy level E_homo of HOMO obtained as a result of the structural optimization calculation by p) is
E_homo> -4.67 (eV)
And the restricted Hartree-Fock method calculation in the stable structure obtained after the structure optimization calculation by the B3LYP / 6-31G (d, p) of the first charge transport material (the basis function is 6-31G ( The calculated value αcal of the polarizability α according to d, p)) is given by the following equation αcal> 70 (Å ³ )
And the energy level E_homo of HOMO obtained as a result of the structural optimization calculation by density functional calculation B3LYP / 6-31G (d, p) of the second charge transport material is
-5.0 <E_homo <-4.67 (eV)
At the maximum indentation depth when measured under the conditions of a maximum indentation load of 5 mN, load duration of 10 s, and unloading duration of 10 s using a Vickers indenter in an environment of 25 ° C and 50% relative humidity. 1. An electrophotographic photosensitive member having a universal hardness of 190 N / mm ² or more and an elastic deformation rate of 45% or more.   The electrophotographic photosensitive member according to claim 1, wherein the content of the first charge transport material is 100 parts by mass or less with respect to 100 parts by mass of the binder resin.   The Mw of the second charge transport material is 500 or less, and the second charge transport material is contained in an amount of 50 parts by mass or less with respect to 100 parts by mass of the binder resin. The electrophotographic photoreceptor described in 1. The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the photosensitive layer contains a polyarylate resin represented by the following general formula [1].

(In the formula [1], Ar ^{1 to} Ar ⁴ each independently represents an arylene group which may have a substituent, and X represents a single bond, an oxygen atom, a sulfur atom, or the following formula [2]. Or a group represented by the following formula [3], wherein R ¹ and R ² in the formula [2] each independently represent a hydrogen atom, an alkyl group, or an aryl group, and R ¹ and R 2 ² may be bonded to form a ring, and R ³ in the formula [3] is an alkylene group, an arylene group, or a group represented by the following formula [4], which is represented by the formula [4] R ⁴ and R ⁵ therein independently represent an alkylene group, Ar ⁵ represents an arylene group, k represents an integer of 0 to 5, provided that when k = 0, Ar ³ and Ar ⁴ Any one of them is an arylene group having a substituent.)

(In Formula [1], Y is a single bond, an oxygen atom, a sulfur atom, or a group represented by the following Formula [5]. In Formula [5], R ⁶ and R ⁷ are each independently (Represents a hydrogen atom, an alkyl group, an alkoxy group, or an aryl group, and R ⁶ and R ⁷ may combine to form a ring.)

The electrophotographic photosensitive member according to any one of claims 1 to 4, wherein the second charge transport material is a compound represented by the following general formula [6] or general formula [7]. body.

(In the general formula [6], Ar ⁶ and Ar ⁷ are aryl groups which may have a substituent having 10 or less carbon atoms constituting the aromatic ring, R represents a substituent other than hydrogen, and n represents 0 during to 7 of an integer. general formula [7], R ^9, R ¹⁰ and R ¹¹ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, or an aryl group, and the R ¹⁰ and R ¹¹ It may be bonded to form a ring.)   6. The electrophotographic photosensitive member according to claim 1, a charging unit for charging the electrophotographic photosensitive member, and exposure for forming an electrostatic latent image by exposing the charged electrophotographic photosensitive member. An electrophotographic photosensitive member comprising: a developing unit that develops an electrostatic latent image formed on the electrophotographic photosensitive member; and a cleaning unit that cleans the electrophotographic photosensitive member. cartridge.   6. The electrophotographic photosensitive member according to claim 1, a charging unit for charging the electrophotographic photosensitive member, and exposure for forming an electrostatic latent image by exposing the charged electrophotographic photosensitive member. And an image forming apparatus comprising: a developing unit that develops an electrostatic latent image formed on the electrophotographic photosensitive member.

Images