JP5446299B2 - Electrophotographic photosensitive member, electrophotographic cartridge using the same, and image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member, an electrophotographic cartridge, and an image forming apparatus used for a copying machine, a printer, and the like.

  In recent years, the use of image forming apparatuses such as electrophotographic copying machines has been expanded, and the market demand for image quality has been increasing. In particular, in office documents, in addition to the development of mapping technology and latent image forming technology for input, the types of character hieroglyphics are more abundant and finer at the time of output. Due to the spread and development, the reproducibility of a latent image with extremely high image quality that has few defects and unclearness in printed images is required. In particular, as a developer used in the case where the electrostatic latent image on the latent image carrier constituting the image forming apparatus is a line image of 100 μm or less (approximately 300 dpi or more), a conventional toner having a large particle diameter has fine line reproducibility. In general, the line image is not clear enough.

To cope with high image quality, it is effective to reduce the particle size of the toner. This technology is good at chemical toners, and various toners have been developed (Patent Documents 1 to 11). In particular, in the case of a chemical toner, it is possible to produce a toner having a narrow particle size distribution, and it is possible to make the charging characteristics uniform, which is advantageous in the electrophotographic process.
On the other hand, as a problem in the case of using a chemical toner, it is mentioned that when the toner shape is close to a sphere, the toner slips between the photosensitive member and the blade, resulting in poor cleaning. Therefore, when chemical toner is used, a method of increasing the contact pressure of the cleaning blade and suppressing defective cleaning is often used. However, in this case, other problems such as blade reversal and rubbing noise are likely to occur. This problem is particularly remarkable when a suspension polymerization toner having a high degree of circularity is used.

  In recent years, since electrophotographic printers and MFPs have been used for SOHO use and home use, demands for space saving and miniaturization have increased more than ever, and there has been a trend toward miniaturization of printers. Accelerating. Along with this, the diameter of electrophotographic photosensitive members has also been reduced. In recent years, electrophotographic photosensitive members having an outer diameter of 30φ are not uncommon, and those having a diameter of 24φ or less are also seen. However, when the outer diameter is reduced, the cleaning blade is likely to be caught, and blade reversal is a greater problem than before.

  As a conventional technique, a polysiloxane block copolymer is used as a binder in order to improve surface slipperiness (for example, see Patent Document 12), and a low molecular weight polysiloxane terminal compound is used (for example, see Patent Document 13). , Using a polysiloxane compound (see, for example, Patent Document 14), and using a fluorine atom-containing polycarbonate (see, for example, Patent Document 15) have been proposed. The current situation includes problems such as adversely affecting printability.

  As another technique, a technique using a cyclic siloxane (Patent Document 16) has been proposed, but this is a residue when a low molecular weight cyclic siloxane is used as a reactive molecule, and the effect of slipperiness is limited. It is.

JP-A-2-284158 JP-A-5-119530 JP-A-1-221755 JP-A-6-289648 JP 2001-134005 A Japanese Patent Laid-Open No. 11-147331 Japanese Patent Laid-Open No. 11-362389 JP-A-2-000877 JP 2004-045948 A JP 2003-255567 A WO2004-088431 JP-A-2-240655 JP 7-261440 A JP 2000-171989 Japanese Patent Laid-Open No. 6-282094 Japanese Patent Laid-Open No. 2003-316042

  The present invention has been made in view of the above-described background art, and the problem is that even when a toner with a high degree of circularity is used or a photoconductor with a small outer diameter is used, the blade does not reverse. Another object of the present invention is to provide an electrophotographic photosensitive member, an electrophotographic cartridge, and an image forming apparatus that are free from problems of cleaning failure, filming, dirt, afterimage (ghost), density reduction, and abnormal noise.

As a result of intensive studies in view of these current situations, the present inventors have used a cyclic polysiloxane having a specific molecular weight in the photosensitive layer, so that the blade is not reversed, resulting in poor cleaning, filming, and dirt. As a result, it was found that no afterimage (ghost), density reduction, or abnormal noise was generated, and the present invention was completed.
That is, the gist of the present invention is that, in an electrophotographic photosensitive member having a photosensitive layer on a conductive support, the photosensitive layer is a cyclic polysiloxane having a molecular weight of 1,000 or more , a chain polysiloxane, and a fat having 10 or more carbon atoms. The electrophotographic photosensitive member is characterized by containing a group hydrocarbon (Claim 1), and in particular, the molecular weight of the cyclic polysiloxane is preferably 5,000 or less (Claim 2). The photosensitive layer further comprises an electrophotographic photosensitive member, wherein the linear polysiloxane polysiloxane is a linear dimethylpolysiloxane (Claim 3), and the photosensitive layer has a molecular weight of at least 1,500 or less. It is preferable to contain a chain polysiloxane and a chain polysiloxane having a molecular weight of 5,000 or more (Claim 4), and in particular, the chain polysiloxane is preferably a chain dimethylpolysiloxane (Claim 5). . Further, the photosensitive layer is an electrophotographic photosensitive member containing a polyarylate resin (Claim 6), and in particular, the aliphatic hydrocarbon is a branched aliphatic hydrocarbon. Preferred (claim 7).

Further, in the electrophotographic photosensitive member, the cleaning mechanism is used in an electrophotographic process which is a counter contact type blade cleaning.
The electrophotographic photosensitive member is characterized in that the outer diameter of the electrophotographic photosensitive member is 10 mm or more and 30 mm or less.
Another gist of the present invention is the electrophotographic photosensitive member, a charging unit for charging the electrophotographic photosensitive member, an image exposing unit for performing image exposure on the charged electrophotographic photosensitive member to form an electrostatic latent image, Among the developing means for developing the electrostatic latent image with toner, the transferring means for transferring the toner from the electrophotographic photosensitive member to the transfer target, and the cleaning means for removing the toner remaining on the organic photosensitive member after the transfer And at least one of the electrophotographic cartridges (Claim 10) and a counter contact type blade cleaning mechanism (Claim 11). In the electrophotographic cartridge, the average circularity of the toner measured by a flow type particle image analyzer is 0.960 or more and 1.000 or less. Claim 12).

  Still another gist of the present invention is that the electrophotographic photosensitive member, at least charging means for charging the electrophotographic photosensitive member, and an image that forms an electrostatic latent image by performing image exposure on the charged electrophotographic photosensitive member. An image forming apparatus comprising: an exposure unit; a developing unit that develops the electrostatic latent image with toner; and a transfer unit that transfers the toner to a transfer target (claim 13). In the image forming apparatus having the contact type blade cleaning mechanism, the average circularity of the toner measured by the flow type particle image analyzer is 0.960 or more and 1.000 or less. It exists in the said image forming apparatus characterized by the above-mentioned (Claim 14).

  According to the present invention, by using a cyclic polysiloxane having a specific molecular weight in the photosensitive layer, blade reversal does not occur, cleaning failure, filming, dirt, afterimage (ghost), density reduction, abnormal noise, etc. There is no occurrence.

1 is a schematic diagram illustrating a main configuration of an embodiment of an image forming apparatus of the present invention. It is an X-ray diffraction diagram showing a powder X-ray diffraction spectrum of oxytitanium phthalocyanine used in Examples and Comparative Examples of the present invention. It is an X-ray diffraction diagram showing a powder X-ray diffraction spectrum of oxytitanium phthalocyanine used in Examples and Comparative Examples of the present invention.

Hereinafter, although an embodiment of the present invention is described in detail, the present invention is not limited to the following description, and can be appropriately implemented without departing from the gist of the present invention.
In the electrophotographic photoreceptor of the present invention, it is essential to use a cyclic polysiloxane having a specific molecular weight in the photosensitive layer.
<Cyclic polysiloxane>
The cyclic polysiloxane having a molecular weight of 1,000 or more used in the present invention is represented by the following formula (1).

  In formula (1), Ra and Rb each independently represent a monovalent organic group, and n represents an integer. X represents a single bond or a divalent linking group. Here, n repeating units in the general formula (1) may be different. That is, the cyclic siloxane compound may be composed of two or more kinds of repeating units having different Ra and Rb. When the number of repeating units is 2 or more, the cyclic siloxane compound may be either a block copolymer or a random copolymer.

  Examples of Ra and Rb include independently a hydrogen atom, an alkyl group which may have a substituent, and an aryl group which may have a substituent. Examples of the alkyl group in Ra and Rb include a methyl group, an ethyl group, and a propyl group. Examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a fluorenyl group. Of these, an alkyl group which may have a substituent is preferable from the viewpoint of electrical characteristics, and a methyl group is particularly preferable. That is, the cyclic polysiloxane is preferably a cyclic dimethylpolysiloxane.

Although n is an integer, it is usually 10 or more, preferably 15 or more, more preferably 20 or more. N is usually 100 or less, preferably 50 or less. A cyclic polysiloxane having a small molecular weight tends to deteriorate the electrical characteristics because it causes a ring-opening reaction. In addition, if the molecular weight is too large, phase separation occurs in the coating solution, so that stable production of the photoreceptor is difficult.
X is a single bond or a divalent linking group. The structure of the divalent linking group is not limited, but preferably has a resin structure unit. Among them, a polycarbonate resin, polyester resin, or polyarylate resin unit is preferable, and these resin structures have ester bonds or ether bonds. It is possible to form a ring with the siloxane unit via any bond such as. However, in the present invention, it is most preferable that X is a single bond in order to sufficiently exhibit the effect of slipperiness.

  In the present invention, the molecular weight of the cyclic polysiloxane is 1,000 or more, preferably 1,500 or more, and more preferably 2,000 or more. Moreover, it is 10,000 or less normally, Preferably it is 5,000 or less, More preferably, it is 3,000 or less. If the molecular weight is too small, a sufficient sliding effect cannot be obtained. If the molecular weight is too large, phase separation occurs in the coating solution, making it difficult to stably produce the photoreceptor. The cyclic polysiloxane used in the present invention preferably has a distribution in molecular weight to some extent, and is preferably a polysiloxane having a molecular weight distribution from 1,500 or less to 2,000 or more.

  In order for the cyclic polysiloxane of the present invention to fully exhibit the effect of slipperiness, 0.003 parts by weight or more, preferably 0.01 parts by weight or more, more preferably 0.00 parts by weight or more with respect to 100 parts by weight of binder resin. 02 parts by weight or more. Further, it is preferably 1 part by weight or less, more preferably 0.5 parts by weight or less, and most preferably 0.1 parts by weight or less. This is because if the number of parts of the cyclic polysiloxane is small, the effect of slipping cannot be obtained, and if it is too large, the electrical characteristics are likely to deteriorate under high temperature and high humidity.

<Linear polysiloxane>
Any known polysiloxane can be used as the chain polysiloxane used in the present invention. As the polysiloxane, either modified or unmodified can be used, but dialkylpolysiloxane is preferable from the viewpoint of electrical characteristics, and dimethylpolysiloxane is preferable from the viewpoint of production.

In formula (2), Rc and Rd each independently represent a monovalent organic group, and m represents an integer. Here, the m repeating units in the general formula (2) may be different. That is, Rc, R
A chain siloxane compound may be composed of two or more repeating units having different d. Moreover, when there are two or more repeating units, the chain siloxane compound may be either a block copolymer or a random copolymer.

  Examples of Rc and Rd include a hydrogen atom, an alkyl group which may have a substituent, and an aryl group which may have a substituent. Examples of the alkyl group in Rc and Rd include a methyl group, an ethyl group, and a propyl group. Examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a fluorenyl group. Among these, an alkyl group which may have a substituent is preferable from the viewpoint of electrical characteristics, and a methyl group is particularly preferable. That is, the chain polysiloxane is preferably a chain dimethylpolysiloxane.

m is an integer, but is usually 10 or more, preferably 15 or more, more preferably 20 or more. N is usually 1000 or less, preferably 200 or less. A linear polysiloxane having a small molecular weight tends to deteriorate the electrical characteristics of the photoreceptor. In addition, if the molecular weight is too large, phase separation occurs in the coating solution, so that stable production of the photoreceptor is difficult.
Any chain polysiloxane having a molecular weight of 100,000 or less can be used. In the present invention, it is preferable to use a polysiloxane having a molecular weight distribution from a low molecular weight to a high molecular weight. Specifically, a distribution from a low molecular weight polysiloxane of 1,500 or less, preferably 1,000 or less, to a high molecular weight polysiloxane of 5,000 or more, preferably 7,000 or more, more preferably 1,000,000 or more. It is preferable to use polysiloxane having

<Aliphatic hydrocarbon>
In the present invention, known aliphatic hydrocarbons having 10 or more carbon atoms used in combination with the cyclic polysiloxane compound can be used. The branched aliphatic hydrocarbon may be branched, linear, or a mixture of a plurality of compounds, but since the linear one is crystallized and easily precipitates in the coating solution, preferable. Moreover, carbon number 16 or more is preferable and carbon number 20 or more is more preferable. Moreover, 100 or less carbon atoms are preferable, and 60 or less carbon atoms are more preferable. If the molecular weight is too small, the effects of the present invention cannot be obtained sufficiently, and if the molecular weight is too large, phase separation tends to occur in the coating solution. In the case of a mixture, the ratio of the compound having 16 or more and 100 or less carbon atoms is preferably 50% or more, and more preferably 80% or more.

The aliphatic hydrocarbon may be saturated or unsaturated, but is preferably a saturated aliphatic hydrocarbon in order to improve slipperiness.
<Conductive support>
As the conductive support used in the electrophotographic photosensitive member of the present invention, 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. Mainly used are resin materials provided with conductivity and resins, glass, paper, and the like obtained by depositing or coating a conductive material such as aluminum, nickel, ITO (indium tin oxide) on the surface. As a form, a drum shape, a sheet shape, a belt shape or the like is used. A conductive material having an appropriate resistance value may be applied to a conductive support made of a metal material in order to control conductivity, surface properties, etc. or to cover defects.

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, an anodic oxidation film is formed by anodizing in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, boric acid, sulfamic acid, etc. give. In the case of anodic oxidation in sulfuric acid, the sulfuric acid concentration is 100 to 300 g / L, the dissolved aluminum concentration is 2 to 15 g / L, the liquid temperature is 15 to 30 ° C., the electrolysis voltage is 10 to 20 V, and the current density is 0.5 to Although it is preferable to set within the range of ² A / dm ² , it is not limited to the above conditions.

It is preferable to perform a sealing treatment on the anodic oxide film thus formed. The sealing treatment may be performed by a known method. For example, it is immersed in an aqueous solution containing nickel fluoride as a main component, or immersed in an aqueous solution containing nickel acetate as a main component. A high temperature sealing treatment is preferably 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 to 6 g / L. Moreover, in order to advance a sealing process smoothly, as processing temperature, it is 25-40 degreeC, Preferably it is 30-35 degreeC, Moreover, nickel fluoride aqueous solution pH is 4.5-6.5, Preferably it is 5 It is better to process in the range of .5 to 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, and 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 5 to 20 g / L. The treatment temperature is 80 to 100 ° C., preferably 90 to 98 ° C., and the pH of the nickel acetate aqueous solution is preferably 5.0 to 6.0.

  Here, aqueous ammonia, 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 supports such as drawing, impact processing, ironing, etc., the process eliminates dirt, foreign matter, etc. on the surface, small scratches, etc., and a uniform and clean support can be obtained. Therefore, it is preferable.

<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. The undercoat layer may be a single layer or a plurality of layers.

Examples of 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, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. One kind of these particles may be used alone, or a plurality of kinds of particles may be mixed and used in an arbitrary combination and ratio.

Among these metal oxide 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. Any one of these treatments may be used, or two or more thereof may be applied.

As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. In addition, the titanium oxide particles may have only one crystal type, or two or more crystal types may be included in any combination and ratio.
Various particle diameters can be used as the particle diameter of the metal oxide particles. Among them, the average primary particle diameter is usually 10 nm or more from the viewpoint of the characteristics of the binder resin as a raw material for the undercoat layer and the stability of the liquid. Usually, it is 100 nm or less, preferably 50 nm or less. This average primary particle size is defined by a value obtained by measurement from a TEM photograph.

  The undercoat layer is preferably formed in a form in which 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, silane coupling agent, and the like. In addition, these may be used independently or may use 2 or more types together by arbitrary combinations and ratios. Moreover, you may use with the hardening | curing form with the hardening | curing agent. Among these, alcohol-soluble copolymerized polyamide, modified polyamide, and the like are preferable because they exhibit good dispersibility and coating properties.

The mixing ratio of the metal oxide particles to the binder resin used for the undercoat layer can be arbitrarily selected, but it is usually applied in the range of 10 to 500 parts by weight with respect to 100 parts by weight of the binder resin. It is preferable in terms of liquid stability and coatability.
When the coating liquid for forming the undercoat layer contains metal oxide particles, the metal oxide particles are present dispersed in the coating liquid. In order to disperse the metal oxide particles in the coating liquid, for example, it can be produced by wet dispersion in an organic solvent with a known mechanical grinding device such as a ball mill, a sand grind mill, a planetary mill, or a roll mill. However, it is preferable to disperse using a dispersion medium.

  As a dispersing device for dispersing using a dispersion medium, any known dispersing device may be used. Pebble mill, ball mill, sand mill, screen mill, gap mill, vibration mill, paint shaker, atomizer Examples include lighters. Among these, those that can be dispersed by circulating the coating solution are preferable, and a sand mill, a screen mill, and a gap mill are used from the viewpoints of dispersion efficiency, fineness of the reached particle diameter, ease of continuous operation, and the like. The sand mill may be either a vertical type or a horizontal type. The disc shape of the sand mill can be any plate type, vertical pin type, horizontal pin type or the like.

In order to disperse the titanium oxide particles in the coating solution for the undercoat layer, those having various particle sizes can be used, but it is preferable to use a dispersion medium having an average particle size of 5 μm to 200 μm.
Since the dispersion medium is generally in the shape of a perfect sphere, the average particle diameter can be obtained by a method of sieving with a sieve described in, for example, JIS Z 8801: 2000 or by image analysis. The density can be measured by the method. Specifically, for example, the average particle diameter and sphericity can be measured by an image analyzer represented by LUZEX50 manufactured by Nireco Corporation. The average particle size of the dispersion medium is usually 5 μm to 200 μm, and preferably 10 μm to 100 μm. In general, a dispersion medium having a small particle diameter tends to give a uniform dispersion in a short time. However, if the particle diameter is excessively small, the mass of the dispersion medium becomes too small to perform efficient dispersion.

The density of the dispersion medium is usually 5.5 g / cm ³ or more, preferably 5.9 g / cm ³ or more, more preferably 6.0 g / cm ³ or more. Generally, dispersion using a higher density dispersion medium tends to give a uniform dispersion in a shorter time. The sphericity of the dispersion medium is preferably 1.08 or less, more preferably a dispersion medium having a sphericity of 1.07 or less.

  The material of the dispersion medium is insoluble in the coating solution for forming the undercoat layer, and has a specific gravity larger than that of the coating solution for forming the undercoat layer. Any known dispersion medium can be used as long as it does not alter the forming coating liquid, and steel balls such as chrome balls (ball balls for ball bearings) and carbon balls (carbon steel balls); stainless steel balls; Examples include ceramic spheres such as silicon nitride spheres, silicon carbide, zirconia, and alumina; spheres coated with a film such as titanium nitride and titanium carbonitride. Among these, ceramic spheres are preferable, and zirconia fired balls are particularly preferable. . More specifically, it is particularly preferable to use zirconia fired beads described in Japanese Patent No. 3400836.

  As disclosed in Japanese Patent Application Laid-Open No. 2007-334335, the metal oxide particles have a volume average particle size of 0.1 μm or less, preferably measured by a dynamic light scattering method in the undercoat layer measurement dispersion. Is 95 nm or less, more preferably 90 nm or less. Moreover, although there is no restriction | limiting in the minimum of the said volume average particle diameter, Usually, it is 20 nm or more. By satisfying the above range, the electrophotographic photosensitive member of the present invention has stable exposure-charging repeat characteristics under low temperature and low humidity, and suppresses occurrence of image defects such as black spots and color spots in the obtained image. it can.

  Similarly, as disclosed in Japanese Patent Application Laid-Open No. 2007-334335, the metal oxide particles have a cumulative 90% particle diameter of 0.3 μm measured by the dynamic light scattering method in the undercoat layer measurement dispersion. Below, it is preferably 0.25 μm or less, more preferably 0.2 μm or less. The lower limit of the cumulative 90% particle size is not limited, but is usually 10 nm or more, preferably 20 nm or more, more preferably 50 nm or more. In a conventional electrophotographic photoreceptor, a metal oxide particle aggregate that is large enough to penetrate the front and back of the undercoat layer is formed by aggregation of metal oxide particles in the undercoat layer, and the large metal oxide particles The agglomerates could cause defects during image formation. Further, when a contact type is used as the charging means, when the photosensitive layer is charged, the charge moves from the photosensitive layer to the conductive support through the metal oxide particles, and the charging is appropriately performed. There was also a possibility that it could not be done. However, in the electrophotographic photosensitive member of the present invention, since the cumulative 90% particle diameter is very small, there are very few large metal oxide particles that cause defects as described above. As a result, in the electrophotographic photosensitive member of the present invention, it is possible to suppress the occurrence of defects and the inability to appropriately charge, and high-quality image formation is possible.

The thickness of the undercoat layer can be arbitrarily selected, but is usually 0 from the viewpoint of improving the electrical characteristics, strong exposure characteristics, image characteristics, repeat characteristics, and applicability at the time of manufacture of the electrophotographic photosensitive member. 0.01 μm or more, preferably 0.1 μm or more, and usually 30 μm or less, preferably 20 μm or less.
<Charge generating material>
The photosensitive layer formed on the conductive support may have a single layer structure in which the charge generation material and the charge transport material are present in the same layer and dispersed in the binder resin, or the charge generation material may be Any of a layered structure (functional separation type photoreceptor) in which a charge generation layer dispersed in a binder and a charge transport material are functionally separated into a charge transport layer dispersed in a binder resin may be used. In the present invention, it is preferable to use a charge generating material and a dye / pigment as necessary. Specific examples thereof include, for example, selenium and its alloys, cadmium sulfide, other inorganic photoconductive materials, phthalocyanine pigments, azo pigments, dithioketopyrrolopyrrole pigments, squalene pigments, quinacridone pigments, indigo pigments, perylene pigments, Various photoconductive materials such as an organic pigment such as a polycyclic quinone pigment, an anthrone pigment, and a benzimidazole pigment can be used, and an organic pigment, a phthalocyanine pigment, and an azo pigment are particularly preferable.

Specific examples of the phthalocyanine used include metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, and other metals, or oxides, halides, hydroxides, and alkoxides thereof. Various crystal forms of such coordinated phthalocyanines are used. Particularly, titanyl phthalocyanines (also known as oxytitanium) such as X-type, τ-type metal-free phthalocyanine, A-type (also known as β-type), B-type (also known as α-type), and D-type (also known as Y-type), which are highly sensitive crystal types Phthalocyanine), vanadyl phthalocyanine, chloroindium phthalocyanine, chlorogallium phthalocyanine such as type II, hydroxygallium phthalocyanine such as type V, μ-oxo-gallium phthalocyanine dimer such as type G and I, IIS
A μ-oxo-aluminum phthalocyanine dimer such as a mold is preferred. 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 27.3 ° 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 the oxytitanium phthalocyanine, the chlorine content in the crystal is preferably 1.5% by mass or less. The chlorine content is determined from elemental analysis.

  Further, in the oxytitanium phthalocyanine crystal, the ratio of the chlorinated oxytitanium phthalocyanine represented by the following formula (2) is higher than that of the unsubstituted oxytitanium phthalocyanine represented by the following formula (3). The ratio is 0.070 or less. The mass spectral intensity ratio is preferably 0.060 or less, more preferably 0.055 or less. In the production, when the dry grinding method is used for amorphization, 0.02 or more is preferable, and when the acid paste method is used for amorphization, 0.03 or less is preferable. The amount of chlorine substitution is measured based on the technique disclosed in Japanese Patent Application Laid-Open No. 2001-115054.

The particle size of these oxytitanyl phthalocyanines varies greatly depending on the production method and the crystal conversion method, but considering the dispersibility, the primary particle size is preferably 500 nm or less, and from the viewpoint of coating film formability, it is preferably 300 nm or less. .
In addition to the chlorinated oxytitanium phthalocyanine, the oxytitanium phthalocyanine may contain, for example, a fluorine atom, a nitro group, or a cyano group. Alternatively, various oxytitanium phthalocyanine derivatives substituted with a substituent such as a sulfone group may be contained.

As the azo pigment, various known bisazo pigments and trisazo pigments are preferably used. An example of a preferable azo pigment is shown in the following formula (4). In the following formula (4), Cp ¹ to Cp ³ represent couplers.

In the above formula (4), the following structures are preferable as the couplers Cp ^{1 to} Cp ³ .

By using phthalocyanine and an azo pigment in combination, it is possible to produce a highly sensitive and ghost-free photoreceptor.
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, silicone-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.

Solvents used for preparing the coating liquid and the dispersion medium for dissolving the binder resin, for example, saturated aliphatic solvents such as pentane, hexane, octane, and nonane,
Aromatic solvents such as toluene, xylene, anisole,
Halogenated aromatic solvents such as chlorobenzene, dichlorobenzene, chloronaphthalene,
Amide solvents such as dimethylformamide and N-methyl-2-pyrrolidone,
Alcohol solvents such as methanol, ethanol, isopropanol, n-butanol, benzyl alcohol,
Aliphatic polyhydric alcohols such as glycerin and polyethylene glycol,
Chain, branched and cyclic ketone solvents such as acetone, cyclohexanone, methyl ethyl ketone, 4-methoxy-4-methyl-2-pentanone,
Ester solvents such as methyl formate, ethyl acetate, n-butyl acetate,
Halogenated hydrocarbon solvents such as methylene chloride, chloroform, 1,2-dichloroethane, chain and cyclic ether solvents such as diethyl ether, dimethoxyethane, tetrahydrofuran, 1,4-dioxane, methyl cellosolve, ethyl cellosolve,
Aprotic polar solvents such as acetonitrile, dimethyl sulfoxide, sulfolane, hexamethylphosphoric triamide,
nitrogen-containing compounds such as n-butylamine, isopropanolamine, diethylamine, triethanolamine, ethylenediamine, triethylenediamine, triethylamine,
Mineral oil such as ligroin,
Examples thereof include water, and those that do not dissolve the above-described 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 (weight) of the binder resin and the charge generation material is 10 to 1000 parts by weight, preferably 30 parts by weight to 100 parts by weight of the binder resin. The thickness is in the range of 500 parts by weight, and the film thickness is usually 0.1 μm to 4 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 is lowered due to problems such as aggregation of the charge generation material. On the other hand, if it is too low, the sensitivity as a photoreceptor is reduced. Is preferred. As a method for dispersing the charge generation material, a known dispersion method such as a ball mill dispersion method, an attritor dispersion method, a sand mill dispersion method, or an ultrasonic 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 material>
In the present invention, a known charge transport material can be used. Examples of known charge transport materials include aromatic nitro compounds such as 2,4,7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, electron withdrawing materials such as quinone compounds such as diphenoquinone, and carbazole derivatives. , Indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, thiadiazole derivatives, heterocyclic compounds such as benzofuran derivatives, aniline derivatives, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives, and a plurality of these compounds Examples thereof include an electron-donating substance such as a polymer in which a species is bonded or a polymer having a group composed of these compounds in the main chain or side chain. Among these, carbazole derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, hydrazone derivatives, enamine derivatives, and those in which a plurality of these compounds are bonded are preferable. Any one of these charge transport materials may be used alone, or two or more thereof may be used in any combination.

Specific examples of suitable structures of the charge transport material are shown below. In the following compounds, R may be the same or different. Specifically, a hydrogen atom, an alkyl group, an alkoxy group, a phenyl group, an arylalkyl and the like are preferable. Particularly preferred is a methyl group, an ethyl group or a benzyl group. N is an integer of 0 to 2. These specific examples are shown for illustration, and any known charge transporting material may be used as long as it does not contradict the gist of the present invention.

The charge transport material of the present invention has a molecular weight of 460 or less, preferably 450 or less, more preferably 430 or less, and most preferably 410 or less. When a polyarylate resin is used as the binder resin, abnormal noise due to rubbing with the cleaning blade tends to occur, but this can be suppressed by using the molecular weight. Although this reason is not certain, it is considered that a CTM having a smaller molecular weight has an effect of improving the slipperiness of the photoreceptor surface. On the other hand, the molecular weight is usually 250 or more, preferably 300 or more, more preferably 320 or more, and most preferably 350 or more. If the molecular weight is too small, the charge transport material sublimates during drying after coating the photosensitive layer, and it is difficult to control the content of the charge transport material in the photosensitive layer.

  The energy level E_homo of HOMO by structure optimization calculation using B3LYP / 6-31G (d, p) of the charge transport material of the present invention is preferably E_homo> −4.67 (eV), and E_homo> −4.65. (EV) is more preferable, E_homo> −4.63 (eV) is further preferable, and E_homo> −4.61 (eV) is most preferable. This is because the higher the HOMO energy level, the lower the potential after exposure and the better the electrophotographic photoreceptor. In particular, when a polyarylate resin is used as the binder resin, the post-exposure potential tends to be higher than when a polycarbonate resin is used. Therefore, it is essential to set E_homo within the specified range in the present invention. It is. On the other hand, if E_homo is too high, problems such as a decrease in gas resistance and generation of ghosts occur, so E_homo <−4.30 (eV) is preferable, E_homo <−4.50 (eV) is more preferable, and E_homo <−4.56 (eV) is most preferred.

  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))). Obtained. At this time, 6-31G (d, p) obtained by adding a polarization function to 6-31G was used as a basis function system (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 the present invention, the program used for B3LYP / 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, J.
C. Burant, JM Millam, SS Iyengar, 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 Hratchian, 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. ).

There are no restrictions on the structure of the charge transporting material for satisfying the above parameters, and enamine derivatives, carbazole derivatives, aniline derivatives, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, and a plurality of these compounds may be used. The thing etc. which couple | bonded are mentioned.
Among these, when the compound represented by the general formula (5) described below is used, the effects of the present invention are particularly exhibited.

(In the formula (5), R1 to R5 each independently represent a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent, and Z represents two carbon atoms of the indoline ring. Together with the formation of a saturated 5- to 8-membered ring and the two hydrogen atoms present on the two carbon atoms are in the cis configuration)
Examples of the alkyl group in R1 to R5 include a methyl group, an ethyl group, and a propyl group. Examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a fluorenyl group. Among these, in consideration of the characteristics of the electrophotographic photoreceptor, a phenyl group and a naphthyl group are preferable, and a phenyl group is most preferable. In addition, examples of the substituent that the alkyl group and the aryl group may have include an alkyl group, an aryl group, an alkoxy group, and an aryloxy group.

  Especially, as R1, the aryl group which may have a substituent is preferable, and the aryl group which has a substituent is more preferable. As the aryl group, a phenyl group is preferable. As a substituent which an aryl group has, an alkyl group or an alkoxy group is preferable, and an alkyl group is most preferable. Specific examples of the alkyl group include a methyl group, an ethyl group, and a propyl group, and a methyl group is most preferable. Specific examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group, and a methoxy group is preferable. By using a phenyl group having these substituents, E_homo can be set high and favorable electrical characteristics can be obtained. It is most preferable that R1 is a p-tolyl group because of a good balance of electric characteristics.

R2 is preferably a hydrogen atom or an alkyl group which may have a substituent, and is preferably a hydrogen atom from the viewpoint of production.
As R3 and R4, an alkyl group which may have a substituent or an aryl group which may have a substituent is preferable, and an aryl group which may have a substituent is particularly preferable in terms of electrical characteristics. As the aryl group, a phenyl group is preferable. As a substituent which an aryl group has, an alkyl group or an alkoxy group is preferable, and an alkyl group is most preferable. Specific examples of the alkyl group include a methyl group, an ethyl group, and a propyl group, and a methyl group is most preferable. Specific examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group, and a methoxy group is preferable. An unsubstituted phenyl group is preferred.

R5 is preferably a hydrogen atom or an alkyl group which may have a substituent, and a hydrogen atom is preferable from the viewpoint of production. n is an integer of 0 to 3, with 0 being most preferred.
Z together with the two carbon atoms of the indoline ring forms a saturated 5- to 8-membered ring. Among these, from the viewpoint of production, a 5- or 6-membered ring is preferable, and a 5-membered ring is most preferable. Two hydrogen atoms existing on two carbon atoms shared by Z and the indoline ring can take a cis or trans configuration. In the present invention, the trans arrangement is distorted in the five-membered ring and E_homo is low, whereas the cis arrangement is high in E_homo, and it has been found that favorable electrical characteristics can be obtained. An example of E_homo of cis and trans is shown below.

以下では、一般式（５）で表される化合物の具体例を例示する。

Below, the specific example of a compound represented by General formula (5) is illustrated.

The charge transport material having the parameters of the present invention may be used in combination with a charge transport material outside the range of the parameters of the present invention. The charge transport material having the parameters of the present invention is usually 30% by weight or more, preferably 50% by weight or more, and more preferably 80% by weight or more and 100% by weight.
Further, the charge transport material having the parameters of the present invention is usually 30 parts by weight or more, preferably 40 parts by weight or more, based on 100 parts by weight of the binder resin, in order to sufficiently exhibit the above-described effects of the present invention. Preferably it is 50 weight part or more. The charge transport material having the parameters of the present invention is preferably 120 parts by weight or less, more preferably 100 parts by weight or less, and most preferably 80 parts by weight or less.

The charge transport material having the parameters of the present invention is particularly effective when a polyarylate resin having a repeating structure represented by the formula [7] described later is used. When polyarylate resin is used, the electrical characteristics deteriorate compared to 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. I can do it. The preferable structure of the polyarylate resin having a repeating structure represented by the formula [7] is the same as that described for the polyarylate resin.
Below, the charge transport material which has the parameter of this invention is illustrated with a parameter.

<Binder resin>
In forming a charge transport layer of a function-separated type photoreceptor having a charge generation layer and a charge transport layer and a photosensitive layer of a single layer type photoreceptor, a binder resin is used to disperse the compound in order to ensure film strength. In the case of the charge transport layer of the functional separation type photoreceptor, a coating solution obtained by dissolving or dispersing the charge transport material and various binder resins in a solvent, and in the case of a single layer type photoreceptor, 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. 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, silicone-alkyd resin, poly-N-vinylcarbazole resin, etc. Is mentioned. These resins may be modified with a silicon reagent or the like. Of the above binder resins, polycarbonate resins or polyarylate resins are preferred.

  As the polycarbonate resin, it is preferable to use a polycarbonate resin having a repeating structure represented by the following formula (6).

In formula (6), Ar ^{21 to} Ar ²² each independently represents an arylene group which may have a substituent, and X ¹ represents a single bond or a divalent linking group.
In the formula (2), Ar ^{21 to} Ar ²² each independently represents an arylene group which may have a substituent. Examples of the arylene group include 1,2-phenylene group, 1,3-phenylene group, 1,4-phenylene group, naphthylene group, anthrylene group, and phenanthrylene group. From the viewpoint of electrical characteristics, 1,4-phenylene group Is preferred.

Moreover, the arylene group which comprises Ar < ²¹ > -Ar < ²² > may have a substituent each independently. Specific examples of the substituent include an alkyl group, an aryl group, a halogen group, and an alkoxy group. Of these, 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 alkyl group is preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, or the like. The group is preferably a phenyl group, a naphthyl group, etc., the halogen group is preferably a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., and the alkoxy group is preferably a methoxy group, an ethoxy group, a propoxy group, a butoxy group, etc. Is done. In addition, when a substituent is an alkyl group, carbon number of the alkyl group is usually 1 or more, and usually 10 or less, preferably 8 or less, more preferably 2 or less.

Ar ^{21 to} Ar ²² each preferably have 0 to 2 substituents, preferably have a substituent from the viewpoint of adhesiveness, and further have one substituent from the viewpoint of slipperiness. preferable. As the substituent, an alkyl group is preferable, and a methyl group is most preferable.
In the formula (6), X ¹ represents a single bond or a divalent linking group. Examples of suitable X ¹ include a sulfur atom, an oxygen atom, a sulfonyl group, a carbonyl group, a cycloalkylidene group, —CRcRd— and the like. Here, Rc and Rd each independently represents a hydrogen atom, an alkyl group, an aryl group, a halogen group, or an alkoxy group. Further, among Rc and Rd, considering the mechanical properties as a binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, the alkyl group includes a methyl group, an ethyl group, a propyl group, and an isopropyl group. The aryl group is preferably a phenyl group, a naphthyl group, etc. The halogen group is preferably a fluorine atom, chlorine atom, bromine atom, iodine atom, etc. The alkoxy group is preferably a methoxy group, ethoxy group, propoxy group, butoxy group Preferred examples include groups. When Rc or Rd is an alkyl group, the alkyl group usually has 1 or more carbon atoms, usually 10 or less, preferably 8 or less, more preferably 2 or less.

Further, considering the simplicity of production of the divalent hydroxy compound used for producing the resin, examples of preferable groups as X ¹ include —O—, —S—, cyclohexylidene group, and —CRcRd—. Can be mentioned. Among them, X ¹ is preferably —CRcRd—, Rc and Rd are preferably a hydrogen atom or an alkyl group, and at least one of Rc and Rd is a hydrogen atom. And most preferred.

Examples of the diol component forming these structures include bisphenol compounds and biphenol compounds.
Specific examples thereof include 4,4′-biphenol, 3,3′-dimethyl-4,4′-dihydroxy-1,1′-biphenyl, 3,3′-di (t-butyl) -4,4 ′. -Dihydroxy-1,1'-biphenyl, 3,3 ', 5,5'-tetramethyl-4,4'-dihydroxy-1,1'-biphenyl, 3,3', 5,5'-tetra (t -Butyl) -4,4'-dihydroxy-1,1'-biphenyl, 2,2 ', 3,3', 5,5'-hexamethyl-4,4'-dihydroxy-1,1'-biphenyl, 2, , 4′-biphenol, 3,3′-dimethyl-2,4′-dihydroxy-1,1′-biphenyl, 3,3′-di (t-butyl) -2,4′-dihydroxy-1,1 ′ -Biphenyl, 2,2'-biphenol, 3,3'-dimethyl-2,2'-dihydroxy-1,1'-biphenyl, 3,3'-di Biphenol compounds such as t- butyl) -2,2'-dihydroxy-1,1'-biphenyl;
Bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) propane, 1, 1-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) pentane, 3,3-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) -3-methylbutane, 1,1-bis (4-hydroxyphenyl) hexane, 2,2-bis (4- Hydroxyphenyl) hexane, 3,3-bis (4-hydroxyphenyl) hexane, 2,2-bis (4-hydroxyphenyl) -4-methyl Pentane, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) bisphenol compounds having no substituents on the aromatic rings such as cyclohexane;
Bis (3-phenyl-4-hydroxyphenyl) methane, 1,1-bis (3-phenyl-4-hydroxyphenyl) ethane, 1,1-bis (3-phenyl-4-hydroxyphenyl) propane, 2,2 A bisphenol compound having an aryl group as a substituent on an aromatic ring such as bis (3-phenyl-4-hydroxyphenyl) propane;
Bis (4-hydroxy-3-methylphenyl) methane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, 1,1-bis (4-hydroxy-3-methylphenyl) propane, 2,2 -Bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane, etc.
Bis (4-hydroxy-3-ethylphenyl) methane, 1,1-bis (4-hydroxy-3-ethylphenyl) ethane, 1,1-bis (4-hydroxy-3-ethylphenyl) propane, 2,2 -Bis (4-hydroxy-3-ethylphenyl) propane, 1,1-bis (4-hydroxy-3-ethylphenyl) cyclohexane, etc.
2,2-bis (4-hydroxy-3-isopropylphenyl) propane, 2,2-bis (4-hydroxy-3- (sec-butyl) phenyl) propane, 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-3,6-dimethylphenyl) methane, 1,1-bis (4-hydroxy-3,6-dimethylphenyl) ethane, 2,2-bis ( 4-hydroxy-3,6-dimethylphenyl) propane, bis (4-hydroxy-2,3,5-trimethylphenyl) methane, 1,1-bis (4-hydride) Xyl-2,3,5-trimethylphenyl) ethane, 2,2-bis (4-hydroxy-2,3,5-trimethylphenyl) propane, bis (4-hydroxy-2,3,5-trimethylphenyl) phenyl On aromatic rings such as methane, 1,1-bis (4-hydroxy-2,3,5-trimethylphenyl) phenylethane, 1,1-bis (4-hydroxy-2,3,5-trimethylphenyl) cyclohexane A bisphenol compound having an alkyl group as a substituent;
Bis (4-hydroxyphenyl) (phenyl) methane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) -1-phenylpropane, bis (4- A bisphenol compound in which a divalent group connecting aromatic rings such as hydroxyphenyl) (diphenyl) methane and bis (4-hydroxyphenyl) (dibenzyl) methane has an aryl group as a substituent;
Among them, a polycarbonate resin having bisphenol and biphenol shown below as a repeating structure is preferably used.

  In particular, in order to maximize the effects of the present invention, a polycarbonate resin containing a bisphenol derivative having the following structure is preferable.

The polycarbonate resin according to the present invention may include a polycarbonate structure other than that represented by the formula (6) as a partial structure. Further, the partial structure may include a structure other than the polycarbonate resin.
In the polycarbonate resin according to the present invention, the larger the weight ratio of the structural portion represented by the formula (6), the more preferable from the viewpoints of electrical characteristics and wear resistance. The structural part represented by the formula (6) is preferably 50% by weight or more, more preferably 70% by weight or more, still more preferably 80% by weight or more based on the total weight of the resin component, Most preferably, the resin component has a structure represented by the formula (6).

In the present invention, a known polyarylate resin can be used.
Among them, a suitable polyarylate resin has a repeating structure represented by the general formula (7).

In formula (7), Ar ^{1 to} Ar ⁴ each independently represent an arylene group which may have a substituent, X and Y each represent a single bond or a divalent linking group, and k is 0 or more. Represents an integer.
In the formula (7), Ar ^{1 to} Ar ⁴ each independently represents an arylene group which may have a substituent. Examples of the arylene group include 1,2-phenylene group, 1,3-phenylene group, 1,4-phenylene group, naphthylene group, anthrylene group, and phenanthrylene group. From the viewpoint of electrical characteristics, 1,4-phenylene group Is preferred.
Moreover, the arylene group which comprises Ar < ¹ > -Ar < ⁴ > may have a substituent each independently. Specific examples of the substituent include an alkyl group, an aryl group, a halogen group, and an alkoxy group. Of these, 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 alkyl group is preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, or the like. The group is preferably a phenyl group, a naphthyl group, etc., the halogen group is preferably a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc., and the alkoxy group is preferably a methoxy group, an ethoxy group, a propoxy group, a butoxy group, etc. Is done. In addition, when a substituent is an alkyl group, carbon number of the alkyl group is usually 1 or more, and usually 10 or less, preferably 8 or less, more preferably 2 or less.

Ar ^{1 to} Ar ² each preferably have 0 to 2 substituents, preferably have a substituent from the viewpoint of adhesion, and further have one substituent from the viewpoint of wear resistance. It is preferable. Further, the substituent is preferably an alkyl group, and most preferably a methyl group.
Ar ^{3 to} Ar ⁴ each preferably have 0 to 2 substituents, and preferably have no substituents in terms of wear resistance.

In the formula (7), X and Y each independently represent a single bond or a divalent linking group. Preferable examples of X and Y include a sulfur atom, an oxygen atom, a sulfonyl group, a cycloalkylidene group, -CRaRb- and the like. Here, Ra and Rb each independently represent a hydrogen atom, an alkyl group, an aryl group, a halogen group, or an alkoxy group. Of Ra and Rb, considering the mechanical properties as a binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, the alkyl group includes a methyl group, an ethyl group, a propyl group, and an isopropyl group. The aryl group is preferably a phenyl group, a naphthyl group, etc. The halogen group is preferably a fluorine atom, chlorine atom, bromine atom, iodine atom, etc. The alkoxy group is preferably a methoxy group, ethoxy group, propoxy group, butoxy group Preferred examples include groups. When R ³ or R ⁴ is an alkyl group, the alkyl group usually has 1 or more carbon atoms, usually 10 or less, preferably 8 or less, more preferably 2 or less.

  Further, considering the simplicity of production of the divalent hydroxy compound used for producing the resin, examples of preferable groups as X include —O—, —S—, cyclohexylidene, and —CRaRb—. . Among these, X is preferably —CRaRb—, Ra and Rb are preferably hydrogen atoms or alkyl groups, and at least one of Ra and Rb is a hydrogen atom in terms of wear resistance. Most preferred.

Further, considering the simplicity of the production of the divalent hydroxy compound used for producing the resin, examples of a group preferable as Y include a single bond, —O—, —S—, and —CH ₂ —. . From the viewpoint of wear resistance, a divalent linking group having 3 or less atoms is preferable, and -O- is most preferable.
k is an integer of 0 or more, preferably 0 to 1 in consideration of the simplicity of production, and most preferably k = 1 from the viewpoint of wear resistance.

  Moreover, as a specific example of the acid component which forms polyarylate resin, it is preferable to use what has the following structures.

  Particularly preferred acid components are those having the following structure from the viewpoints of electrical properties and wear resistance.

Examples of the diol used for the polyarylate resin include bisphenol compounds and biphenol compounds.
Specific examples thereof include 4,4′-biphenol, 3,3′-dimethyl-4,4′-dihydroxy-1,1′-biphenyl, 3,3′-di (t-butyl) -4,4 ′. -Dihydroxy-1,1'-biphenyl, 3,3 ', 5,5'-tetramethyl-4,4'-dihydroxy-1,1'-biphenyl, 3,3', 5,5'-tetra (t -Butyl) -4,4'-dihydroxy-1,1'-biphenyl, 2,2 ', 3,3', 5,5'-hexamethyl-4,4'-dihydroxy-1,1'-biphenyl, 2, , 4′-biphenol, 3,3′-dimethyl-2,4′-dihydroxy-1,1′-biphenyl, 3,3′-di (t-butyl) -2,4′-dihydroxy-1,1 ′ -Biphenyl, 2,2'-biphenol, 3,3'-dimethyl-2,2'-dihydroxy-1,1'-biphenyl, 3,3'-di Biphenol compounds such as t- butyl) -2,2'-dihydroxy-1,1'-biphenyl;
Bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) propane, 1, 1-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) pentane, 3,3-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxyphenyl) -3-methylbutane, 1,1-bis (4-hydroxyphenyl) hexane, 2,2-bis (4- Hydroxyphenyl) hexane, 3,3-bis (4-hydroxyphenyl) hexane, 2,2-bis (4-hydroxyphenyl) -4-methyl Pentane, 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) bisphenol compounds having no substituents on the aromatic rings such as cyclohexane;
Bis (3-phenyl-4-hydroxyphenyl) methane, 1,1-bis (3-phenyl-4-hydroxyphenyl) ethane, 1,1-bis (3-phenyl-4-hydroxyphenyl) propane, 2,2 A bisphenol compound having an aryl group as a substituent on an aromatic ring such as bis (3-phenyl-4-hydroxyphenyl) propane;

Bis (4-hydroxy-3-methylphenyl) methane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, 1,1-bis (4-hydroxy-3-methylphenyl) propane, 2,2 -Bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane, etc.
Bis (4-hydroxy-3-ethylphenyl) methane, 1,1-bis (4-hydroxy-3-ethylphenyl) ethane, 1,1-bis (4-hydroxy-3-ethylphenyl) propane, 2,2 -Bis (4-hydroxy-3-ethylphenyl) propane, 1,1-bis (4-hydroxy-3-ethylphenyl) cyclohexane, etc.
2,2-bis (4-hydroxy-3-isopropylphenyl) propane, 2,2-bis (4-hydroxy-3- (sec-butyl) phenyl) propane, 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-3,6-dimethylphenyl) methane, 1,1-bis (4-hydroxy-3,6-dimethylphenyl) ethane, 2,2-bis ( 4-hydroxy-3,6-dimethylphenyl) propane, bis (4-hydroxy-2,3,5-trimethylphenyl) methane, 1,1-bis (4-hydride) Xyl-2,3,5-trimethylphenyl) ethane, 2,2-bis (4-hydroxy-2,3,5-trimethylphenyl) propane, bis (4-hydroxy-2,3,5-trimethylphenyl) phenyl On aromatic rings such as methane, 1,1-bis (4-hydroxy-2,3,5-trimethylphenyl) phenylethane, 1,1-bis (4-hydroxy-2,3,5-trimethylphenyl) cyclohexane A bisphenol compound having an alkyl group as a substituent;
Bis (4-hydroxyphenyl) (phenyl) methane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) -1-phenylpropane, bis (4- A bisphenol compound in which a divalent group connecting aromatic rings such as hydroxyphenyl) (diphenyl) methane and bis (4-hydroxyphenyl) (dibenzyl) methane has an aryl group as a substituent;
Among these, a polyarylate resin having a diol having the following structure as a repeating unit structure is a preferred example.

These dicarboxylic acid components and diol components can be used in combination.
In the polyarylate resin according to the present invention, the larger the weight ratio of the structural portion represented by the formula (7), the more preferable from the viewpoints of electrical characteristics and wear resistance. The structural portion represented by the formula (7) is preferably 50% by weight or more, more preferably 70% by weight or more, still more preferably 80% by weight or more based on the total weight of the resin component, Most preferably, the resin component has a structure represented by the formula (7).

The repeating structure of the resin suitably used as the polyarylate resin according to the present invention is exemplified below. However, the polyarylate resin according to the present invention is not limited thereto.

・ Repeated structure when k is 0

・ Repeated structure when k is 1

  If the molecular weight of the binder resin is too low, the mechanical strength is insufficient. Conversely, if the molecular weight is too high, the viscosity of the coating solution for forming the photosensitive layer may be too high, resulting in a decrease in productivity. The viscosity average molecular weight is preferably 10,000 or more, particularly preferably 20,000 or more. Moreover, 70,000 or less is preferable, Most preferably, it is 50,000 or less. The viscosity average molecular weight is measured by the measuring method described in the examples and is defined thereby.

  The amount of carboxyl group (—COOH group) present at the end of the polyarylate resin used in the present invention is usually 30 μeq / g or less, preferably 15 μeq / g or less, more preferably 10 μeq / g or less, particularly preferably 5 μeq / g or less. It is. When the amount of the terminal carboxyl group is increased, there is a tendency that electric characteristics such as an increase in surface potential are deteriorated, which is not preferable. Further, the lower the amount of the terminal carboxylic acid group, the more the charge transport material can be prevented from being decomposed. The amount of terminal carboxyl group can be quantified by dissolving a precisely weighed polyarylate resin in benzyl alcohol and titrating with a 0.01 N NaOH benzyl alcohol solution.

The amount of nitrogen incorporated in the molecular chain of the polyarylate used in the present invention is usually 100 ppm or less, preferably 50 ppm or less, and particularly preferably 20 ppm or less. If the nitrogen content exceeds the above range, electrical characteristics such as an increase in surface potential are deteriorated, which is not preferable. The nitrogen content in the resin can be measured with a total nitrogen analyzer (TN-10) manufactured by Mitsubishi Chemical Corporation.
The amount of the acid chloride group remaining at the terminal of the polyarylate resin is usually 1 μeq / g or less, preferably 0.3 μeq / g or less, particularly preferably 0.1 μeq / g or less. When the amount of the terminal acid chloride group exceeds the above range, the storage stability is lowered, which is not preferable. The amount of the terminal acid chloride group is obtained by dissolving a precisely weighed polyarylate resin in methylene chloride, adding a 1 wt% methylene chloride solution of 4- (p-nitrobenzyl) pyridine, and measuring the absorbance at a wavelength of 440 nm. Separately, an extinction coefficient can be obtained using a methylene chloride solution of benzoyl chloride to quantify the amount of acid chloride groups in the resin.

  Similarly, the amount of OH groups present at the terminal of the polyarylate resin is not usually limited, but is preferably 50 μeq / g or less, particularly preferably 20 μeq / g or less. An increase in the amount of terminal OH groups is not preferable because electric characteristics such as an increase in surface potential tend to be deteriorated. The amount of terminal OH groups can be quantified by coloring with titanium tetrachloride by acidification with acetic acid and measuring the absorbance at a wavelength of 480 nm.

  In the present invention, a resin other than the polyarylate resin described later can be used in combination as the binder resin. However, the polyarylate resin is usually 30% by weight or more, preferably 50% by weight or more, more preferably 80% of the total binder resin used in the charge transport layer of the multilayer photoreceptor and the photosensitive layer of the single-layer photoreceptor. Most preferably, it is made of a polyarylate resin of at least% by weight.

  The ratio of the binder resin and the charge transport material used in the charge transport layer of the multilayer photoconductor and the photosensitive layer of the single layer photoconductor is usually charged to 100 parts by weight of the binder resin in both the single layer type and the multilayer type. The transport material is 20 parts by weight or more, preferably 30 parts by weight or more from the viewpoint of reducing the residual potential, and more preferably 40 parts by weight or more from the viewpoint of stability during repeated use and charge mobility. On the other hand, from the viewpoint of thermal stability of the photosensitive layer, it is usually 150 parts by weight or less, preferably 120 parts by weight or less from the viewpoint of compatibility between the charge transport material and the binder resin, and 100 parts by weight from the viewpoint of printing durability. Part or less is more preferable, and 80 parts by weight or less is particularly preferable from the viewpoint of scratch resistance.

  In the case of a single-layer type photoreceptor, the charge generating substance is further dispersed in the charge transport medium having the above-described blending ratio. In this case, the particle size of the charge generating material needs to be sufficiently small, preferably 1 μm or less, more preferably 0.5 μm or less. If the amount of the charge generating material dispersed in the photosensitive layer is too small, sufficient sensitivity may not be obtained. On the other hand, if the amount is too large, adverse effects such as a decrease in chargeability and a decrease in sensitivity may occur. For example, it is preferably used in the range of 0.1 to 50% by mass, particularly preferably in the range of 1 to 20% by mass.

The film thickness of the photosensitive layer of the single-layer type photoreceptor is usually 5 to 100 μm, preferably 10 to 50 μm. The film thickness of the charge transport layer of the forward laminated photoreceptor is usually 5 to 50 μm. Although used, it is preferably 10 to 45 μm from the viewpoint of long life and image stability, and more preferably 10 to 30 μm from the viewpoint of high resolution.
<Others>
The photosensitive layer has well-known antioxidants, plasticizers, ultraviolet absorbers, electron-withdrawing compounds to improve film-forming properties, flexibility, coating properties, stain resistance, gas resistance, light resistance, etc. Further, additives such as a leveling agent and a visible light shading agent may be contained. In addition, the photosensitive layer may contain various additives such as a leveling agent, an antioxidant, and a sensitizer for improving the coating property as necessary. Examples of the antioxidant include hindered phenol compounds and hindered amine compounds. Examples of dyes and pigments include various pigment compounds and azo compounds. Examples of surfactants include silicone oil and fluorine oil.

  Examples of phenolic antioxidants include 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-ethylphenol, 2,6-di-t-butyl-4-methylphenol, 2,2′-methylenebis (6-t-butyl-4-methylphenol), 4,4′-butylidenebis (6-t-butyl-3-methylphenol), 4,4′-thiobis (6-t-butyl) -3-methylphenol), 2,2′-butylidenebis (6-t-butyl-4-methylphenol), α-tocopherol, β-tocopherol, 2,2,4-trimethyl-6-hydroxy-7-t- Butylchroman, pentaerythrityltetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,2′-thioethylenebis [3- (3,5 -Di-t-butyl-4-hydroxyphenyl) propionate], 1,6-hexanediol bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], butylhydroxyanisole, dibutylhydroxy Anisole, 1- [2-{(3,5-di-butyl-4-hydroxyphenyl) propionyloxy} ethyl] -4- [3- (3,5-di-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperazyl, 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5- Triazine, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 2- (5-methyl-2- Droxyphenyl) benzotriazole, 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 1- [2- {3- (3,5-di-t-butyl) -4-hydroxyphenyl) propionyloxy} ethyl] -4- {3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy} -2,2,6,6-tetramethylpiperidine, n -Octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, etc. can be mentioned.

  Among these, those having one or more t-butyl groups on the phenol ring in the molecule are preferable, and among them, those in which the t-butyl group is bonded to the position adjacent to the phenolic hydroxyl group are more preferable. Among them, the one in which two t-butyl groups are bonded to the position adjacent to the phenolic hydroxyl group is most preferable. Specific examples thereof include 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-ethylphenol, 2,6-di-t-butyl-4-methylphenol, and n-octadecyl. Monophenolic antioxidants such as -3- (4'-hydroxy-3 ', 5'-di-t-butylphenyl) propionate, 2,2'-methylenebis (6-t-butyl-4-methylphenol) 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, pentaerythrityltetrakis [3- (3,5-di-t- Polyphenolic antioxidants such as butyl-4-hydroxyphenyl) propionate] are preferred. By using these, an electrophotographic photoreceptor free from fogging can be produced even when used repeatedly.

Moreover, in order to improve acid-proof gas resistance, it is possible to use the alkylamine compound which may have a well-known substituent. For example, it is effective to use compounds disclosed in JP-A-3-172852 and JP-A-2007-52408. Among these, for example, tribenzylamine can be preferably used.
A protective layer may be provided on the outermost surface layer of the photosensitive member for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to a discharge substance generated from a charger or the like. The protective layer is formed by containing a conductive material in a suitable binder resin, or a co-polymer using a compound having a charge transporting ability such as a triphenylamine skeleton as described in JP-A-9-190004. Coalescence can be used. Examples of the conductive material include aromatic amino compounds such as TPD (N, N′-diphenyl-N, N′-bis- (m-tolyl) benzidine), antimony oxide, indium oxide, tin oxide, titanium oxide, and tin oxide. -Metal oxides such as 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 protective layer is preferably configured to have an electric resistance of 10 ⁹ to 10 ¹⁴ Ω · cm. When the electric resistance is higher than 10 ¹⁴ Ω · cm, the residual potential is increased and an image with much fogging is formed. On the other hand, when the electric resistance is lower than 10 ⁹ Ω · cm, the image is blurred and the resolution is lowered. In addition, the protective layer must be configured so as not to substantially impede transmission of light irradiated for image exposure.

Also, 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 has a fluorine resin, silicone resin, polyethylene resin, polystyrene resin, etc. May be included. Moreover, the particle | grains which consist of these resin, and the particle | grains of an inorganic compound may be included.
<Electrophotographic photoreceptor>
The electrophotographic photosensitive member of the present invention is preferably one having a small outer diameter because it can prevent the cleaning blade from being involved in the downsizing of an image forming apparatus such as an electrophotographic printer. That is, the outer diameter of the photoreceptor is preferably 100 mm or less, more preferably 50 mm or less, and particularly preferably 30 mm or less. On the other hand, the lower limit is preferably 3 mm or more, more preferably 5 mm or more, and particularly preferably 10 mm or more from an industrial viewpoint. Within the above range, the present invention has a more remarkable effect.

<Layer formation method>
Each layer constituting the photoreceptor is formed by sequentially applying a coating solution containing the material constituting each layer on the support using a known coating method and repeating the coating and drying process for each layer. The
In the case of the charge transport layer of the single layer type photoreceptor and the multilayer type photoreceptor, the coating solution for forming the layer is usually used in a solid content concentration of 5 to 40% by mass, but 10 to 35% by mass. It is preferable to use in the range. Moreover, although the viscosity of this coating liquid is normally used in the range of 10-500 mPa * s, it is preferable to set it as the range of 50-400 mPa * s.

In the case of the charge generating layer of the multilayer photoreceptor, the solid content is usually used in the range of 0.1 to 15% by mass, but more preferably in the range of 1 to 10% by mass. Although the viscosity of a coating liquid is normally used in the range of 0.01-20 mPa * s, it is more preferable to be used in the range of 0.1-10 mPa * s.
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 and then heating and drying in a temperature range of 30 to 200 ° C. for 1 minute to 2 hours with no air or air. The heating temperature may be constant or may be changed while drying.
<Toner according to the present invention>
When image formation is performed using the electrophotographic photosensitive member of the present invention, a toner as a developer for developing a latent image is a toner having a specific circularity (hereinafter referred to as “the toner of the present invention” as appropriate). Is preferably used. By using the toner having a specific circularity as described above, the image forming apparatus of the present invention can form a high-quality image.

<Toner circularity>
The shape of the toner of the present invention is such that the shape of each particle included in the particle group constituting the toner is closer to each other, and the closer to a sphere, the less likely the localization of the charge amount in the toner particles occurs. The developability tends to be uniform, which is preferable for improving the 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 of the present invention has an average circularity measured by a flow particle image analyzer of usually 0.960 or more, preferably 0.970 or more, more preferably 0.975 or more, particularly Preferably it is 0.980 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 average circularity is measured using a flow type particle image analyzer FPIA-2000 manufactured by Sysmex Corporation. Then, the circularity [a] of the measured particle is obtained by the following formula (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 of the present invention 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 of the toners of the present invention can be used.
Hereinafter, the toner manufacturing method and the type of toner will be described.

The toner of the present invention may be produced by any conventionally known method, for example, a toner produced by a polymerization method or a melt suspension method, and further, a so-called pulverized toner is treated with heat or the like. Although a spheroidized toner can be used, a toner produced by a so-called polymerization method that generates toner particles in an aqueous medium is preferable.
As a toner method 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. The toner is produced by a direct polymerization in the presence of a water-soluble polar polymerization initiator or a dispersion polymerization method in which a toner is produced directly using an aqueous organic solvent that is soluble in monomers and insoluble in a polymer obtained. 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 weight 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 weight). 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 of obtaining a fine particle toner having a sharp particle size distribution and a particle diameter of 3 to 8 μm, which can control the average circularity of the toner to 0.960 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 the toner according to the present invention is produced using the suspension polymerization method, as a specific method for encapsulating the low softening point substance, the polarity of the substance in the aqueous medium may be lower than that of the main monomer. The 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 setting the direction smaller and adding a small amount of a resin or monomer having a large polarity. Toner particle size distribution control and particle size control can be done by changing the type and amount of dispersant that acts as a water-insoluble inorganic salt or protective colloid, as well as mechanical device conditions such as rotor peripheral speed, number of passes, and stirring blades. The predetermined toner of the present invention can be obtained by controlling the stirring conditions such as the shape, 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 of 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 toner storage stability and developer durability stability. On the other hand, when it exceeds 75 ° C., the fixing point is raised, and in particular, full-color toner. In this case, the color toners are not sufficiently mixed and the color reproducibility is poor, and 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 weight 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. Particularly, as a full-color toner, it is extremely high in molecular weight, which is disadvantageous for the color mixture of four-color toners. 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 outer shell resin layer preferably contains a polar resin or a charge control agent in order to improve chargeability.

Further, the method for providing the outer 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 composed of 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 weight based on 100 parts by weight of the resin. When a magnetic material is used as the black colorant, 40 to 150 parts by weight are added to 100 parts by weight 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 and has a high toner charging speed and can stably maintain a constant charge amount. Is preferred. 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 weight with respect to 100 parts by weight 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-based 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 weight 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 the 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, Examples thereof include magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, magnetic substance, and ferrite. 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 dispersed in an aqueous phase. These dispersants are preferably used in an amount of 0.2 to 10.0 parts by weight with respect to 100 parts by weight 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 preferred dispersant 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 weight part surfactant for refinement | miniaturization of these dispersing agents. Specifically, commercially available nonionic, anionic and cationic surfactants can be used, such as sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, olein. Acid calcium or the like is preferably used.

  When the direct polymerization method is used as the toner production method used in the present invention, the toner can be produced specifically 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 flocculant is added to the dispersion to agglomerate the primary particles to form particle aggregates (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 description will be given of a method of performing emulsion polymerization using wax as a seed, thereby obtaining polymer primary particles.
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 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 polymerization is performed. 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 weight or more, preferably 5 parts by weight or more, and usually 40 parts by weight or less, preferably 30 parts by weight or less based on 100 parts by weight 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, but the emulsifier is usually used at a ratio of 1 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer.
(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 (personal SC meter model SC72 and detector SC72SN-11 manufactured by Yokogawa Electric Corporation).

Moreover, although there is no restriction | limiting in the usage-amount of a liquid medium, The quantity of about 1-20 weight 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, the polymerization initiator is usually used at a ratio of 0.05 to 2 parts by weight with respect to 100 parts by weight of the polymerizable monomer.
(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. Yes

(Meth) acrylic acid ester to be used.
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 weight or more, preferably 0 with respect to 100 parts by weight of the total polymerizable monomer. It is desirable that the amount be 5 parts by weight or more, more preferably 1 part by weight or more, and usually 10 parts by weight or less, preferably 5 parts by weight 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 weight part of polymeric monomers is 0.005 weight part or more normally, Preferably it is 0.00. 1 part by weight or more, more preferably 0.3 part by weight or more, and usually 5 parts by weight or less, preferably 3 parts by weight or less, more preferably 1 part by weight 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 weight part or less with respect to 100 weight part of polymerizable monomers.
Further, any known colloid that can be used for this purpose can be used. Specific examples include partially or fully 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). At.

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 weight 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. This is because when a styrene resin in which at least one of the number average molecular weight and the weight average molecular weight, preferably both falls within the above ranges, is used as the polymer, the obtained toner has good durability, storage stability and fixability. is there. Further, the molecular weight distribution may have two main peaks. The styrene resin refers to a resin in which styrenes occupy usually 50% by weight or more, preferably 65% by weight or more based on the total polymer.

  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 with a nozzle 1 mm × 10 mm, a load of 30 kg, a preheating time of 50 ° C. for 5 minutes, and a temperature rising rate of 3 ° C./min in a flow tester. 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 combined polymer particles is usually 5% by weight or less, preferably 4% by weight or less, more preferably 3% by weight or less based on the total of the polymer primary particles and the polymer of the combined 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 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, since carbon black of the channel method tends to have a large amount of impurities, carbon black produced by the furnace method is preferred as the toner of the present invention.
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. At this time, the amount of the pigment particles used in the pigment particle dispersion is usually 3 parts by weight or more, preferably 5 parts by weight or more, and usually 50 parts by weight or less, preferably 40 parts by weight with respect to 100 parts by weight of the liquid medium. 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 increases. 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.

The ratio of the amount of the pigment used relative to the polymer contained in the polymer primary particles is usually 1% by weight or more, preferably 3% by weight or more, and usually 20% by weight or less, preferably 15% by weight 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 which occupies for a pigment particle dispersion is 10 to 50 weight% 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 at 25 ° C. using a conductivity meter (personal SC meter model SC72 and detector SC72SN-11 manufactured by Yokogawa Electric Corporation).

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, Usually 0.01 weight part or more with respect to 100 weight part of polymers, Preferably it is 0.1 weight part or more, Moreover, 10 weight part or less, Preferably it is 5 weight part 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. Especially, the method of mixing electrolyte is preferable.
Examples of the electrolyte when the agglomeration is performed by mixing the electrolyte include chlorides such as NaCl, KCl, LiCl, MgCl ₂ , 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 weight or more, preferably 0.1 parts by weight or more, and usually 25 parts by weight or less, based on 100 parts by weight of the solid component in the emulsion. Preferably it is 15 weight part or less, More preferably, it is 10 weight part or less. When agglomeration is performed by mixing electrolytes, if the amount of electrolyte used is too small, the agglomeration reaction proceeds slowly and fine particles of 1 μm or less remain after the agglomeration reaction, and the average particle size of the obtained agglomerates 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 arbitrary, it is usually 10 minutes or longer, preferably 60 minutes or longer, and usually 300 minutes or shorter, preferably 180 minutes or shorter.

In addition, stirring is preferably performed when the aggregation is performed. 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 it is usually 1% by weight or more, preferably 5% by weight or more, and usually 50% by weight or less, preferably 25% by weight 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 weight or more, preferably 0.05% by weight or more, more preferably 0.08% by weight or more, and usually 2% by weight or less in the toner. Preferably it is 1 weight% or less, More preferably, you may be 0.5 weight% 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 step, 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 normally 5 (degreeC) or more 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 "the temperature 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, after the fusing step, the encapsulated resin particles obtained are washed and dried to remove the liquid medium, thereby obtaining a toner. There are no restrictions on the washing and drying methods, and they are arbitrary.

<Physical properties relating to toner particle size>
There is no restriction on the volume average particle size [Dv] of the toner of the present invention, and it is optional as long as the effect of the present invention is not significantly impaired, but it is usually 4 μm or more, preferably 5 μm or more, and usually 10 μm or less, preferably 8 μm or less. It is. 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.

  In the toner of the present invention, the value [Dv / Dn] obtained by dividing the volume average particle diameter [Dv] by the number average particle diameter [Dn] is usually 1.0 or more, and usually 1.25 or less, preferably It is desirable that it is 1.20 or less, more preferably 1.15 or less. 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 of the present invention has a volume fraction having a particle diameter of 25 μm or more, usually 1% or less, preferably 0.5% or less, more preferably 0.1% or less, and further 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.

In the toner of the present invention, the volume fraction having a particle size of 15 μm or more is 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, in the toner of the present invention, it is desirable that the number fraction having a particle size of 5 μm or less is usually 15% or less, preferably 10% or less, since this is effective in improving 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. In other words, a Coulter Counter Multisizer II or III (manufactured by Beckman Coulter, Inc.) is used as a toner particle size measuring device, and an interface for outputting the number distribution and volume distribution and a general personal computer are connected. And use it. 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 is measured with 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. The volume average particle diameter [Dv] and the number average particle diameter [
Dn] is obtained.

<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 of the present invention is usually 10,000 or more, preferably 20,000 or more, more preferably 3 It is usually 10,000 or less, preferably 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, as measured by a weight 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 of the present invention 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 with the sample concentration (resin concentration) adjusted to 0.05 to 0.6% by weight. 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.

Further, 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 restriction on the softening point [Sp] of the toner of the present invention, 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 softening point [Sp] of the toner 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, the glass transition temperature [Tg] of the toner of the present invention is not limited, and may be arbitrary as long as the effects of the present invention are not significantly impaired. Usually, the fixing temperature is 80 ° C. or lower, preferably 70 ° C. or lower. It is desirable because it is possible. 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 of the present invention contains a 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 it is 1 micrometer or less. 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 ratio of the wax in the toner is arbitrary as long as the effects of the present invention are not significantly impaired, but is usually 0.05% by weight or more, preferably 0.1% by weight or more, and usually 20% by weight or less, preferably Is 15% by weight 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 weight of the toner and the externally added fine particles is usually 0.1% by weight or more, preferably 0.3% by weight or more, more preferably 0.5% by weight or more, and usually 10%. It is desirable that the content is not more than wt%, preferably not more than 6 wt%, more preferably not more than 4 wt%. 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 of the present invention may be negatively charged or positively charged, and can be set according to the type of 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.

Further, the toner of the present invention can be used as a one-component developer, or mixed with a carrier and used as a two-component developer.
When used as a two-component developer, the carrier that is mixed with the toner to form the developer may be, for example, a known magnetic substance such as an iron powder, ferrite, or magnetite carrier, or a resin 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 in a ratio of 5 to 100 parts by weight with respect to 1 part by weight 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.
[Image forming apparatus and electrophotographic cartridge]
Next, an embodiment of an image forming apparatus using the electrophotographic photosensitive member of the present invention (an image forming apparatus of the present invention) will be described with reference to FIG. However, the embodiment is not limited to the following description, and can be arbitrarily modified without departing from the gist of the present invention.

As shown in FIG. 1, the image forming apparatus includes an electrophotographic photosensitive member 1, a charging device 2, an exposure device 3, and a developing device 4, and further, a transfer device 5, a cleaning device 6 and a fixing device as necessary. A device 7 is provided.
The electrophotographic photoreceptor 1 is not particularly limited as long as it is the above-described electrophotographic photoreceptor of the present invention, but in FIG. 1, as an example, a drum in which the above-described photosensitive layer is formed on the surface of a cylindrical conductive support. The photoconductor is shown. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5 and a cleaning device 6 are arranged along the outer peripheral surface of the electrophotographic photosensitive member 1, respectively.

The charging device 2 charges the electrophotographic photosensitive member 1 and uniformly charges the surface of the electrophotographic photosensitive member 1 to a predetermined potential. Examples of the charging device include a corona charging device such as a corotron and a scorotron, a direct charging device (contact type charging device) that charges a direct charging member to which a voltage is applied by contacting the photosensitive member surface, and a contact type charging device such as a charging brush. Often used. Examples of direct charging means include contact chargers such as charging rollers and charging brushes. In FIG. 1, a roller-type charging device (charging roller) is shown as an example of the charging device 2. As the direct charging means, either charging with air discharge or injection charging without 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.

The type of the exposure apparatus 3 is not particularly limited as long as it can expose the electrophotographic photoreceptor 1 to form an electrostatic latent image on the photosensitive surface of the electrophotographic photoreceptor 1. Specific examples include halogen lamps, fluorescent lamps, lasers such as semiconductor lasers and He—Ne lasers, LEDs, and the like. Further, exposure may be performed by a photoreceptor internal exposure method. The light used for the exposure is arbitrary. For example, the exposure may be performed using monochromatic light with a wavelength of 780 nm, monochromatic light with a wavelength slightly shorter than 600 nm to 700 nm, or monochromatic light with a short wavelength of 380 nm to 500 nm. . Among these, it is preferable to use light having a short wavelength of 380 to 500 nm because the resolution becomes high. Among these, 405 nm monochromatic light is preferable. Moreover, the writing resolution is mainly 600 dpi or more at present, but there is a high-performance model having 1200 dpi. The resolution of the electrostatic latent image and the toner image is determined depending on the writing resolution, and the higher the resolution, the clearer the image is obtained. Therefore, a resolution of 1200 dpi or higher is preferable. For example, when writing is performed with an LED having a resolution of 600 dpi and 1200 dpi, the minimum dot formation interval is 42 μm and 21 μm, respectively.

  The type of the developing device 4 is not particularly limited, and an arbitrary device such as a dry development method such as cascade development, one-component insulating toner development, one-component conductive toner development, or two-component magnetic brush development, or a wet development method is used. be able to. In FIG. 1, the developing device 4 includes a developing tank 41, an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45, and is configured to store toner T inside the developing tank 41. . Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing device 4 as necessary. The replenishing device is configured to be able to replenish toner T from a container such as a bottle or a cartridge. In the present embodiment, the toner of the present invention described above is preferably used as the toner T.

The supply roller 43 is formed from a conductive sponge or the like. The developing roller 44 is made of a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating such a metal roll with a silicone resin, a urethane resin, a fluorine resin, or the like. The surface of the developing roller 44 may be smoothed or roughened as necessary.
The developing roller 44 is disposed between the electrophotographic photosensitive member 1 and the supply roller 43 and is in contact with the electrophotographic photosensitive member 1 and the supply roller 43, respectively. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism (not shown). The supply roller 43 carries the stored toner T and supplies it to the developing roller 44. The developing roller 44 carries the toner T supplied by the supply roller 43 and contacts the surface of the electrophotographic photosensitive member 1.

  The regulating member 45 is formed of a resin blade such as silicone resin or urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such a metal blade with resin. The regulating member 45 contacts the developing roller 44 and is pressed against the developing roller 44 side with a predetermined force by a spring or the like (a general blade linear pressure is 5 to 500 g / cm). If necessary, the regulating member 45 may be provided with a function of imparting charging to the toner T by frictional charging with the toner T.

The agitator 42 is rotated by a rotation driving mechanism, and agitates the toner T and conveys the toner T to the supply roller 43 side. A plurality of agitators 42 may be provided with different blade shapes and sizes.
The type of the transfer device 5 is not particularly limited, and an apparatus using an arbitrary system such as an electrostatic transfer method such as corona transfer, roller transfer, or belt transfer, a pressure transfer method, or an adhesive transfer method can be used. . Here, it is assumed that the transfer device 5 includes a transfer charger, a transfer roller, a transfer belt, and the like that are disposed to face the electrophotographic photoreceptor 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner T, and transfers the toner image formed on the electrophotographic photosensitive member 1 to a recording paper (paper, medium) P. Is.

  There is no restriction | limiting in particular about the cleaning apparatus 6, Arbitrary cleaning apparatuses, such as a brush cleaner, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, can be used. The cleaning device 6 is for scraping off residual toner adhering to the photoreceptor 1 with a cleaning member and collecting the residual toner. If there is little or almost no toner remaining on the surface of the photoreceptor, the cleaning device 6 may be omitted.

  Among these, the blade cleaning method is preferable because of its simple structure, small size, low cost, and excellent cleaning performance and reliability. The blade cleaning method can be classified into a contact method and a pressurization method (57th Annual Meeting of the Imaging Society of Japan P196-211). The contact method is classified into counter contact and forward contact, and the pressurization method is classified into a low displacement method and a low load method.

In the present invention, a blade cleaning method is preferable for effectively removing the toner. In particular, when a toner having a high degree of circularity is used, the counter contact method is preferable because the toner easily slips between the blade and the photoreceptor. . The linear pressure of the blade against the photosensitive member is preferably set to 20-60 g / cm.
If the blade is set under the above conditions, there is a tendency that a rubbing sound is generated between the photosensitive member and the blade, but this can be avoided by using the photosensitive member of the present invention.

  The fixing device 7 includes an upper fixing member (fixing roller) 71 and a lower fixing member (fixing roller) 72, and a heating device 73 is provided inside the fixing member 71 or 72. FIG. 1 shows an example in which a heating device 73 is provided inside the upper fixing member 71. The upper and lower fixing members 71 and 72 include a fixing roll in which a metal base tube made of stainless steel, aluminum or the like is coated with silicon rubber, a fixing roll in which Teflon (registered trademark) resin is coated, a fixing sheet, or the like. A member can be used. Further, each of the fixing members 71 and 72 may be configured to supply a release agent such as silicone oil in order to improve releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

When the toner transferred onto the recording paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated to a molten state and cooled after passing through the recording paper. Toner is fixed on P.
The type of the fixing device is not particularly limited, and a fixing device of any type such as heat roller fixing, flash fixing, oven fixing, pressure fixing, etc. can be provided including those used here.

In the electrophotographic apparatus configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the photoreceptor 1 is charged to a predetermined potential (for example, −600 V) by the charging device 2. At this time, charging may be performed by a DC voltage, or charging may be performed by superimposing an AC voltage on the DC voltage.
Subsequently, the photosensitive surface of the charged photoreceptor 1 is exposed by the exposure device 3 according to the image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. The developing device 4 develops the electrostatic latent image formed on the photosensitive surface of the photoreceptor 1.

The developing device 4 thins the toner T supplied by the supply roller 43 with a regulating member (developing blade) 45 and has a predetermined polarity (here, the same polarity as the charging potential of the photosensitive member 1) and the negative polarity. ), And conveyed while being carried on the developing roller 44 to be brought into contact with the surface of the photoreceptor 1.
When the charged toner T carried on the developing roller 44 comes into contact with the surface of the photoreceptor 1, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the photoreceptor 1. This toner image is transferred onto the recording paper P by the transfer device 5. Thereafter, the toner remaining on the photosensitive surface of the photoreceptor 1 without being transferred is removed by the cleaning device 6.

After the transfer of the toner image onto the recording paper P, the final image is obtained by passing the fixing device 7 and thermally fixing the toner image onto the recording paper P.
In addition to the above-described configuration, the image forming apparatus may have a configuration capable of performing, for example, a static elimination process. The neutralization step is a step of neutralizing the electrophotographic photosensitive member by exposing the electrophotographic photosensitive member, and a fluorescent lamp, an LED, or the like is used as the neutralizing device. In addition, the light used in the static elimination process is often light having an exposure energy that is at least three times that of the exposure light.

The image forming apparatus may be further modified. For example, the image forming apparatus may be configured to perform a pre-exposure process, an auxiliary charging process, or the like, or may be configured to perform offset printing. A full-color tandem system configuration using toner may be used.
The electrophotographic photosensitive member 1 is combined with one or more of the charging device 2, the exposure device 3, the developing device 4, the transfer device 5, the cleaning device 6, and the fixing device 7 to form an integrated cartridge ( The electrophotographic cartridge may be configured to be detachable from the main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. In this case, for example, when the electrophotographic photosensitive member 1 or other member is deteriorated, this electrophotographic cartridge is removed from the main body of the image forming apparatus, and another new electrophotographic cartridge is mounted on the main body of the image forming apparatus. Equipment maintenance and management are easy.

[Example]
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. Note that “parts” used in this example represents “parts by weight” unless otherwise specified.

Production Example 1
100 parts of a polycarbonate resin represented by the following repeating structure (resin 1, viscosity average molecular weight 40,000), 70 parts of CTM1 represented by the following formula as a charge transport material, 20 parts of CTM2 and the following formula as an antioxidant 8 parts of a compound represented by formula (AOX1), 0.12 part of a chain dimethylpolysiloxane, 0.05 part of a cyclic dimethylpolysiloxane, 0.03 part of a branched aliphatic hydrocarbon having 21 to 25 carbon atoms are added to tetrahydrofuran / toluene ( 8/2 (weight ratio)) A charge transport layer forming coating solution was prepared by dissolving in 640 parts of a mixed solvent.

However, the chain dimethylpolysiloxane used here has a molecular peak corresponding to n = 18 in the following formula when measured in the positive mode with a MALDI-TOF / MS apparatus Voyager-De ^™ STR manufactured by Applied Biosystems. Having a maximum intensity, a peak having a molecular weight of 1,500 or less and a peak having an intensity of 50% or more of the maximum intensity peak, and a molecular weight of 5,000 or more having a peak having an intensity of 10% or more of the maximum intensity peak; Moreover, it is a chain dimethylpolysiloxane composition having a peak having a molecular weight of 7,000 or more and a peak intensity of 5% or more of the peak of maximum intensity.

  In addition, the cyclic dimethylpolysiloxane used here has a maximum molecular peak corresponding to n = 16 in the following formula when measured in the positive mode with the MALDI-TOF / MS apparatus, and has a molecular weight of 2 It is a cyclic dimethylpolysiloxane composition having a peak having an intensity of 10% or more of the peak of maximum intensity at 1,000 or more.

Production Example 2
Instead of the polycarbonate resin (resin 1) used in the coating liquid for forming the charge transport layer in Production Example 1, a polycarbonate resin (resin 2, viscosity average molecular weight 40,000) represented by the following repeating structure was used to charge transport. A coating solution for forming a charge transport layer was prepared in the same manner as in Production Example 1, except that 80 parts of CTM3 represented by the following formula was used instead of CTM1 and CTM2.

Production Example 3
Instead of the polycarbonate resin (resin 1) used in the coating liquid for forming the charge transport layer in Production Example 1, a polyarylate resin (resin 3, viscosity average molecular weight 43,000) represented by the following repeating structure was used. A coating solution for forming a charge transport layer was prepared in the same manner as in Production Example 1 except that 80 parts of CTM3 was used instead of CTM1 and CTM2 as the transport material.

Production Example 4
Instead of the polycarbonate resin (resin 1) used in the coating liquid for forming the charge transport layer of Production Example 1, 50 parts of resin 2 and 50 parts of resin 3 were used, and CTM 3 was used instead of CTM 1 and CTM 2 as charge transport materials. In the same manner as in Production Example 1 except that the chain polydimethylsiloxane was 0.18 part, the cyclic polysiloxane was 0.075 part, and the branched aliphatic hydrocarbon having 21 to 25 carbon atoms was 0.045 part. A coating solution for transport layer formation was prepared.
Production Example 5 Instead of the polycarbonate resin (resin 1) used in the coating liquid for forming the charge transport layer in Production Example 1, resin 3 was used, and CTM4 represented by the following formula was used instead of CTM1 and CTM2 as charge transport materials. A coating solution for forming a charge transport layer was prepared in the same manner as in Production Example 1 except that 80 parts of was used.

Production Example 6
Instead of the polycarbonate resin (resin 1) used in the coating liquid for forming the charge transport layer of Production Example 1, resin 3 was used, and CTM5 represented by the following formula was used as a charge transport material instead of CTM1 and CTM2 of 80 parts. A charge transport layer forming coating solution was prepared in the same manner as in Production Example 1 except that it was used.

Comparative production example 1
The chain dimethylpolysiloxane, cyclic dimethylpolysiloxane, and branched aliphatic hydrocarbon used in the coating liquid for forming the charge transport layer in Production Example 1 were not used. Instead, dimethylpolysiloxane KF96-10CS manufactured by Shin-Etsu Chemical Co., Ltd. was replaced with 0. A coating solution for forming a charge transport layer was prepared in the same manner as in Production Example 1 except that 2 parts were used.

Comparative production example 2
The chain dimethylpolysiloxane, cyclic dimethylpolysiloxane, and branched aliphatic hydrocarbon used in the coating liquid for forming the charge transport layer in Production Example 1 were not used. Instead, dimethylpolysiloxane KF96-100CS manufactured by Shin-Etsu Chemical Co., Ltd. was changed to 0. A coating solution for forming a charge transport layer was prepared in the same manner as in Production Example 1 except that 2 parts were used.

Comparative production example 3
The chain dimethylpolysiloxane, cyclic dimethylpolysiloxane, and branched aliphatic hydrocarbon used in the coating liquid for forming the charge transport layer in Production Example 1 were not used. Instead, dimethylpolysiloxane KF96-10CS manufactured by Shin-Etsu Chemical Co., Ltd. was replaced with 0. .10 parts, a coating solution for forming a charge transport layer was prepared in the same manner as in Production Example 1 except that 0.10 parts of branched paraffin VYBAR260 manufactured by Toyo Petrolite Co. was used.

Comparative production example 4
The chain dimethylpolysiloxane, cyclic dimethylpolysiloxane, and branched aliphatic hydrocarbon used in the charge transport layer forming coating solution of Production Example 3 were not used. Instead, Shin-Etsu Chemical Co., Ltd. dimethylpolysiloxane KF96-10CS was changed to 0. A coating solution for forming a charge transport layer was prepared in the same manner as in Production Example 3 except that 2 parts were used.

Example 1
On an aluminum cylinder having an outer diameter of 24 mm, a length of 257 mm, and a wall thickness of 0.75 mm with a mirror-finished surface, the following coating solution for forming an undercoat layer, coating solution for forming a charge generation layer, and for forming a charge transport layer The coating liquid is sequentially applied by a dip coating method, and an undercoat layer, a charge generation layer, and a charge transport layer are formed so that the film thicknesses after drying are 1.3 μm, 0.4 μm, and 15 μm, respectively. Got.

  The undercoat layer forming coating solution was prepared as follows. 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 mixed using a Henschel mixer. The surface-treated titanium oxide obtained by mixing was dispersed by a ball mill in a mixed solvent having a methanol / 1-propanol weight ratio of 7/3 to obtain a surface-treated titanium oxide dispersed slurry. The dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam [compound represented by the following formula (A)] / bis (4-amino-3-methylcyclohexyl) methane [following formula (B) Compound represented by the following formula] / hexamethylenediamine [compound represented by the following formula (C)] / decamethylene dicarboxylic acid [compound represented by the following formula (D)] / octadecamethylene dicarboxylic acid [represented by the following formula (E) The composition is made up of 60% / 15% / 5% / 15% / 5% of the copolymerized polyamide pellets with heating and stirring and mixing to dissolve the polyamide pellets. By performing the dispersion treatment, the weight ratio of methanol / 1-propanol / toluene is 7/1/2, and the surface-treated titanium oxide / copolymer In a weight ratio of 3/1 to polyamide to prepare a coating liquid for forming an undercoat layer having a solid concentration of 18.0%.

  The charge generation layer forming coating solution was prepared as follows. As a charge generation substance, 20 parts of oxytitanium phthalocyanine shown in the X-ray diffraction spectrum of FIG. 2 and 280 parts of 1,2-dimethoxyethane were mixed, and pulverized with a sand grind mill for 1 hour for atomization dispersion treatment. Subsequently, 10 parts of polyvinyl butyral (trade name “Denka Butyral” # 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.) was added to 255 parts of 1,2-dimethoxyethane and 4-methoxy-4-methyl. A binder solution obtained by dissolving in 85 parts of a mixed solution of 2-pentanone and 230 parts of 1,2-dimethoxyethane were mixed to prepare a coating solution A for forming a charge generation layer.

  As a charge generation material, 20 parts of oxytitanium phthalocyanine shown in the X-ray diffraction spectrum of FIG. 3 and 280 parts of 1,2-dimethoxyethane were mixed and pulverized with a sand grind mill for 4 hours for atomization dispersion treatment. Subsequently, 10 parts of polyvinyl butyral (trade name “Denka Butyral” # 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.) was added to 255 parts of 1,2-dimethoxyethane and 4-methoxy-4-methyl. A binder solution obtained by dissolving in 85 parts of a mixture of 2-pentanone and 230 parts of 1,2-dimethoxyethane were mixed to prepare a coating solution B for forming a charge generation layer.

The charge generation layer forming coating solution A and the charge generation layer forming coating solution B were mixed at a ratio of 6.5: 3.5 to prepare a charge generation layer forming coating solution used in this example.
The coating liquid prepared in Production Example 1 was used as the coating liquid for forming the charge transport layer.
An image characteristic test described later was performed using the photosensitive drum produced here and a toner having a volume average particle diameter of 6.1 μm and an average circularity of 0.990.
A good image without image deterioration such as ghost, fog, density reduction, filming, and poor cleaning was obtained at the initial stage and after the 1,000-sheet image formation. In addition, no abnormal noise was generated during printing.
The results are shown in Table 1.

<Image characteristics test>
The image characteristic test was performed using a color printer HP Color LaserJet CP1518ni (tandem method, cleaning blade, counter contact method) manufactured by Hewlett-Packard Company.

The produced photosensitive drum and toner were mounted on a cyan process cartridge, and this cartridge was mounted on a printer. It was confirmed whether or not blade reversal occurred when image formation was performed in an environment of temperature 25 ° C. and humidity 50%. The same operation was performed 10 times by replacing the photosensitive drum, and the ranking was performed as follows according to the number of times of blade reversal.
◎: 0 times, ○: 1 to 2 times, Δ: 3 to 4 times, ×: 5 times or more Further, 1,000 images were formed and evaluated for ghost, fogging, density reduction, filming, and poor cleaning. Went.

Filming was ranked as follows.
○: Not generated, △: Slightly generated, ×: Generated

実施例２〜６
実施例１において用いた製造例１で作製した電荷輸送層形成用塗布液の代わりに、製造
例２〜６で作製した電荷輸送層形成用塗布液を用いた以外は、実施例１と同様にして評価を行った。結果を表１に示した。

Examples 2-6
Instead of the charge transport layer forming coating solution prepared in Production Example 1 used in Example 1, the charge transport layer forming coating solution prepared in Production Examples 2 to 6 was used. And evaluated. The results are shown in Table 1.

Comparative Examples 1-4
Similar to Example 1 except that the charge transport layer forming coating solution prepared in Comparative Production Examples 1 to 4 was used instead of the charge transport layer forming coating solution prepared in Production Example 1 used in Example 1. And evaluated. The results are shown in Table 1.
Example 7
On the aluminum cylinder having a mirror-finished outer diameter of 30 mm, length of 260.5 mm, and wall thickness of 0.75 mm, the following undercoat layer forming coating solution, charge generating layer forming coating solution, and charge transport layer The coating liquid for forming is applied in order by dip coating, and an undercoat layer, a charge generation layer, and a charge transport layer are formed so that the film thickness after drying is 1.3 μm, 0.4 μm, and 25 μm, respectively. I got a body drum.

The undercoat layer forming coating solution was the same as that prepared in Example 1.
The charge generation layer forming coating solution was prepared by mixing the charge generation layer forming coating solution A and the charge generation layer forming coating solution B prepared in Example 1 at a ratio of 8: 2.
The coating liquid prepared in Production Example 1 was used as the coating liquid for forming the charge transport layer.
An image characteristic test described later was performed using the photosensitive drum produced here and a toner having a volume average particle diameter of 7.0 μm and an average circularity of 0.990.

A good image without image deterioration such as ghost, fog, density reduction, filming, and poor cleaning was obtained at the initial stage and after the 10,000-sheet image formation. In addition, no abnormal noise was generated during printing.
The results are shown in Table 2.
<Image characteristics test>
The image characteristic test was performed using a color printer HP Color LaserJet 4700dn (cleaning blade, counter contact method) manufactured by Hewlett-Packard Company.

  The produced photosensitive drum and toner were mounted on a cyan process cartridge, and this cartridge was mounted on a printer. 10,000 images were formed under an environment of a temperature of 25 ° C. and a humidity of 50%, and ghost, fog, density reduction, filming, and poor cleaning were evaluated.

Examples 8-9
Evaluation was conducted in the same manner as in Example 7 except that the charge transport layer forming coating solution shown in Table 2 was used instead of the charge transport layer forming coating solution prepared in Production Example 1 used in Example 7. went. The results are shown in Table 2.

Comparative Example 5
Evaluation was conducted in the same manner as in Example 7 except that the charge transport layer forming coating solution shown in Table 2 was used instead of the charge transport layer forming coating solution prepared in Production Example 1 used in Example 7. went. The results are shown in Table 2.
From the examples in Tables 1 and 2, the electrophotographic photosensitive member having a cyclic polysiloxane having a molecular weight of 1,000 or more in the present invention has good slipperiness and can suppress blade reversal that tends to occur in the initial stage. When the conventional chain polysiloxane (Comparative Examples 1 and 2) and the branched aliphatic hydrocarbon (Comparative Example 3) are used, sufficient effects cannot be obtained. The reason is not clear, but as one factor, it is thought that cyclic polysiloxane is easy to bleed on the surface, and a great effect can be obtained even in a small amount.

In particular, when a charge transport material having a molecular weight of 460 or less is used, no abnormal noise is generated (Examples 1 to 4 and Examples 7 to 8), and when a polyarylate resin is used, there is no other problem and particularly excellent. (Examples 3-4, 8)
In the present invention, when a photosensitive drum having a small outer diameter is used, the problem of blade reversal is particularly likely to occur (Comparison between Comparative Examples 1 to 4 and Comparative Example 5). In particular, a drum having an outer diameter of 24 mm or less is used. When used, the effect of the technique of the present invention is remarkable.

  With the recent miniaturization of printers, the electrophotographic photosensitive member of the present invention has excellent characteristics as a technique necessary for a small-diameter electrophotographic photosensitive member.

  The present invention can be used in any field where an electrophotographic photosensitive member is used, and is particularly suitable for use in an image forming apparatus such as a printer or a copying machine.

1 Photoconductor 2 Charging device (charging roller)
DESCRIPTION OF SYMBOLS 3 Exposure apparatus 4 Developing apparatus 5 Transfer apparatus 6 Cleaning apparatus 7 Fixing apparatus 41 Developing tank 42 Agitator 43 Supply roller 44 Developing roller 45 Control member 71 Upper fixing member (pressure roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper

Claims (15)

In an electrophotographic photosensitive member having a photosensitive layer on a conductive support, the photosensitive layer contains at least a cyclic polysiloxane having a molecular weight of 1,000 or more , a chain polysiloxane, and an aliphatic hydrocarbon having 10 or more carbon atoms. An electrophotographic photoreceptor characterized by the above.   2. The electrophotographic photosensitive member according to claim 1, wherein the cyclic polysiloxane is cyclic dimethylpolysiloxane. The electrophotographic photosensitive member according to claim 1 or 2 molecular weight of the cyclic polysiloxane, characterized in der Rukoto 5,000.   4. The electrophotographic photosensitive member according to claim 3, wherein the chain polysiloxane contains at least a chain polysiloxane having a molecular weight of 1,500 or less and a chain polysiloxane having a molecular weight of 5,000 or more.   The electrophotographic photosensitive member according to claim 3 or 4, wherein the chain polysiloxane is a chain dimethylpolysiloxane. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer contains a polyarylate resin .   The electrophotographic photosensitive member according to claim 6, wherein the aliphatic hydrocarbon is a branched aliphatic hydrocarbon.   8. The electrophotographic photosensitive member according to claim 1, wherein the electrophotographic photosensitive member is used in an electrophotographic process in which the cleaning mechanism is a counter contact type blade cleaning.   The electrophotographic photosensitive member according to any one of claims 1 to 8, wherein an outer diameter of the photosensitive member is 10 mm or more and 30 mm or less. The electrophotographic photosensitive member according to claim 1, a charging unit for charging the electrophotographic photosensitive member, and image exposure is performed on the charged electrophotographic photosensitive member to form an electrostatic latent image. Image exposing means, developing means for developing the electrostatic latent image with toner, transfer means for transferring the toner from the electrophotographic photosensitive member to the transfer target, and toner remaining on the organic photosensitive member after the transfer are removed. An electrophotographic cartridge comprising at least one of cleaning means.   The electrophotographic cartridge according to claim 10, further comprising a counter contact type blade cleaning mechanism.   12. The electrophotographic cartridge according to claim 10, wherein the average circularity of the toner measured by a flow type particle image analyzer is 0.960 or more and 1.000 or less.   An electrophotographic photosensitive member according to any one of claims 1 to 9, a charging means for charging at least the electrophotographic photosensitive member, and image exposure is performed on the charged electrophotographic photosensitive member to form an electrostatic latent image. An image forming apparatus comprising: an image exposing unit to be formed; a developing unit that develops the electrostatic latent image with toner; and a transfer unit that transfers the toner to a transfer target.   The image forming apparatus according to claim 13, further comprising a counter contact type blade cleaning mechanism.   The image forming apparatus according to claim 13 or 14, wherein an average circularity of the toner measured by a flow type particle image analyzer is 0.960 or more and 1.000 or less.

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