JP2009091304A - Amine compound mixture, electrophotographic photoreceptor, image-forming method and image-forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor that prevents deterioration in sensitivity liable to occur on high-speed copy or in a low-temperature low-humidity environment, prevents a black spot liable to occur by the surface contamination of an electrophotographic photoreceptor, causes no fracturing flaws such as a crack or the like and stably affords a clear electrophotographic image of high resolution, and to provide an image-forming method, an image-forming apparatus and an amine compound mixture used for the same. <P>SOLUTION: The amine compound mixture comprises an amine compound represented by formula (1) where Ar<SB>1</SB>-Ar<SB>4</SB>satisfy equation (1): Ar<SB>1</SB>=Ar<SB>2</SB>=Ar<SB>3</SB>=Ar<SB>4</SB>and an amine compound represented by the formula (1) where Ar<SB>1</SB>-Ar<SB>4</SB>satisfy equation (2): Ar<SB>1</SB>=Ar<SB>2</SB>=Ar<SB>3</SB>≠Ar<SB>4</SB>. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member, an image forming method, an image forming apparatus, and an amine compound mixture used therefor, which are used for electrophotographic image formation used in the field of copying machines and printers.

  Currently, an electrophotographic apparatus using a laser as a light source, such as a laser printer, is used. As the light source laser, a semiconductor laser that emits light having a wavelength of 780 to 800 nm or 680 nm is mainly used. However, in recent years, there has been a strong demand for higher image quality and higher resolution of output images, and various attempts have been made to meet this demand. One of them is to reduce the spot diameter of the writing light. In order to reduce the spot diameter, it is possible to theoretically make the writing light source shorter by theoretically reducing the wavelength of the writing light source, which is very advantageous for increasing the writing density of the latent image, that is, the resolution. Therefore, it is desired to develop a highly sensitive and highly stable electrophotographic photosensitive member corresponding to an LD or LED oscillation light source in the 350 to 500 nm region.

  One of the development requirements for an electrophotographic photoreceptor corresponding to this short wavelength light source is the development of a charge transport material that does not absorb in the vicinity of the 350 to 500 nm region of the writing light source. Currently, many of the charge transport materials used in electrophotographic photoreceptors have absorption on the short wavelength side. Therefore, when such a charge transport material is used for an electrophotographic photoreceptor exposed with a short wavelength light source. , Sensitivity decreases.

  In response to this problem, a triarylamine compound has been proposed as a charge transport material suitable for an electrophotographic photosensitive member that is exposed to a light source having a short wavelength (see, for example, Patent Documents 1 and 2). However, since this compound has low solubility in ordinary solvents and poor compatibility with binders, the coating solution for forming a photosensitive layer of an electrophotographic photoreceptor has poor storage stability, and crystals are precipitated during storage. As a result, it is not possible to fill the electrophotographic photosensitive member with a sufficient concentration of this compound, resulting in poor sensitivity, or high crystallinity, so that cracks are likely to occur. There was a problem that occurred.

As a countermeasure against this, a method of mixing several kinds of charge transport materials having different chemical structures has been proposed (see, for example, Patent Documents 3 and 4). However, this method has a problem that sensitivity and high-speed response are lowered although solubility is improved. Since the chemical structures are different, the charge transfer between the compounds is not smooth, and the electrical characteristics are considered to be deteriorated.
JP 2000-105475 A JP 2001-350282 A JP 2004-78147 A Japanese Patent Laid-Open No. 2002-40688

  The present invention has been made in view of the above problems, and its purpose is to prevent a reduction in sensitivity that is likely to occur in high-speed copying and low-temperature, low-humidity environments, and to prevent black spots that are likely to occur due to surface contamination of the electrophotographic photosensitive member. In addition, an electrophotographic photosensitive member, an image forming method, an image forming apparatus, and an amine compound used in the electrophotographic photosensitive member capable of stably obtaining a high-resolution clear electrophotographic image without causing occurrence of breakage such as cracks. It is to provide a mixture.

  The above object of the present invention is achieved by the following configurations.

1. In the following general formula (1), Ar _{1 to} Ar ₄ contain an amine compound that satisfies the following formula (1) and an amine compound that satisfies the following formula (2).

(In the formula, R ₁ and R ₂ represent an alkyl group or an aryl group, and R ₁ and R ₂ may be linked to form a cyclic structure. Ar ₅ and Ar ₆ may have a substituent. Represents an arylene group.)
Formula (1) Ar ₁ = Ar ₂ = Ar ₃ = Ar ₄
Formula (2) Ar ₁ = Ar ₂ = Ar ₃ ≠ Ar ₄
2. An amine compound mixture obtained by reacting an amine compound represented by the following general formula (2) with two or more halogenated aryl compounds represented by the following general formula (3).

(In the formula, R ₁ and R ₂ represent an alkyl group or an aryl group, and R ₁ and R ₂ may be linked to form a cyclic structure. Ar ₅ and Ar ₆ may have a substituent. Represents an arylene group.)

(In the formula, Ar represents an aryl group which may have a substituent, and X represents a halogen atom.)
3. 3. The amine compound mixture according to 2 above, which is obtained by reacting the amine compound represented by the general formula (2) with two kinds of halogenated aryl compounds represented by the general formula (3) body.

  4). X1 and X2 satisfy the following formulas (3) to (5) when the contents (mass%) of the amine compound satisfying the formula (1) and formula (2) are X1 and X2, respectively. 4. The amine compound mixture according to any one of 1 to 3 above.

Formula (3) 30 ≦ X1 + X2 <100
Formula (4) 20 <= X1 <= 95
Formula (5) 5 <= X2 <= 45
5). An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer contains the amine compound mixture described in any one of 1 to 4 above.

  6). 6. The electrophotographic photoreceptor as described in 5 above, wherein the photosensitive layer has a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material.

  7. An exposure process for forming an electrostatic latent image on an electrophotographic photosensitive member using a semiconductor laser having an oscillation wavelength of 350 to 500 nm or a light source of a light emitting diode, and a developing process for visualizing the electrostatic latent image into a toner image An image forming method comprising: an electrophotographic photosensitive member as described in 5 or 6 above.

  8). Exposure means for forming an electrostatic latent image on an electrophotographic photosensitive member using a semiconductor laser having an oscillation wavelength of 350 to 500 nm or a light source of a light emitting diode, and developing means for developing the electrostatic latent image into a toner image An image forming apparatus comprising: the electrophotographic photosensitive member according to 5 or 6 above.

  According to the present invention, it is possible to prevent sensitivity deterioration that is likely to occur in high-speed copying and low-temperature and low-humidity environments, to prevent black spots that are likely to occur due to surface contamination of the electrophotographic photosensitive member, and to generate fractures such as cracks. Thus, an electrophotographic photosensitive member, an image forming method, an image forming apparatus, and an amine compound mixture used therefor, which can stably obtain a clear high-resolution electrophotographic image without causing any trouble, can be provided.

As a result of intensive studies in view of the above problems, the present inventor has found that, in the general formula (1), Ar _{1 to} Ar ₄ satisfy the formula (1), and the amine compound satisfies the formula (2). By using an amine compound mixture containing as a charge transport material, it prevents the sensitivity reduction that is likely to occur in high-speed copying and low-temperature and low-humidity environments, and prevents black spots that are likely to occur due to surface contamination of the electrophotographic photosensitive member. In addition, an electrophotographic photosensitive member, an image forming method, an image forming apparatus, and an amine compound mixture used in the electrophotographic photosensitive member capable of stably obtaining a clear high-resolution electrophotographic image without causing cracks and the like. As a result, the present invention has been found.

  An amine compound in which the structure of one of the same amine compound and amino moiety is changed with respect to an electrophotographic photoreceptor produced using an amine compound having poor solubility but good sensitivity characteristics (hereinafter also referred to simply as a photoreceptor). A photoreceptor using the above mixture can improve the solubility without impairing the electrical characteristics and prevent image quality deterioration after the durability test. On the other hand, a photoreceptor using a mixture of amine compounds with completely different structures caused poor sensitivity and deteriorated initial characteristics.

  Table 1 shows the relationship between the mixed combination pattern of the amine compound of the present invention, the solubility and the electrophotographic photoreceptor characteristics.

  The reason why such an effect can be obtained is that the amine compound to be mixed is equivalent to the amine compound having good electrical characteristics by having the same structure of one amino moiety and the same divalent linking group. Therefore, it is considered that the charge transfer between the compounds is easy and the solubility can be remarkably improved. On the other hand, although the electrical characteristics are good, when two or more amine compounds having different structures are used, the solubility is improved, but the transfer of charges between the compounds is not smooth, which leads to deterioration of the electrical characteristics. it is conceivable that.

In the general formula (1), Ar _{1 to} Ar ₄ may be mixed after synthesizing several kinds of amine compounds (cannot be mixed) satisfying the formula (1). It is more cost-effective and technically easy to synthesize at a time by reaction of an amine compound with two or more types of halogenated aryl compounds.

  Hereinafter, the present invention will be described in detail.

<< Amine compound mixture >>
In the present invention, as the charge transport material, in the general formula (1), an amine compound in which Ar _{1 to} Ar ₄ satisfy the formula (1) and an amine compound that satisfies the formula (2) are used in combination.

In the general formula (1), R ₁ and R ₂ may represent an alkyl group or an aryl group, and R ₁ and R ₂ may be linked to form a cyclic structure. Ar ₅ and Ar ₆ represent an arylene group which may have a substituent.

Examples of the alkyl group include alkyl groups having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an isopropyl group, a 2-methylpropyl group, and an n-butyl group. Examples of the aryl group include a phenyl group and a tolyl group. R ₁ and R ₂ may be linked to form a saturated hydrocarbon ring having 4 to 8 carbon atoms, and preferably a cyclohexane ring which may have a methyl group or an ethyl group on the ring.

  As the arylene group which may have a substituent, a phenylene group or a tolylene group is preferable, and a phenylene group is particularly preferable. Examples of the substituent of the arylene group include an alkyl group having 1 to 4 carbon atoms or an alkoxy group.

  In the present invention, as the charge transport material, an amine obtained by reacting the amine compound represented by the general formula (2) with two or more halogenated aryl compounds represented by the general formula (3) A compound mixture is used.

In the general formula (2), R ₁ and R ₂ may represent an alkyl group or an aryl group, and R ₁ and R ₂ may be linked to form a cyclic structure. Ar ₅ and Ar ₆ represent an arylene group which may have a substituent. These alkyl groups, aryl groups, cyclic structures, and arylene groups which may have a substituent have the same meanings as the groups and cyclic structures described in the general formula (1).

  In the general formula (3), Ar represents an aryl group which may have a substituent, and X represents a halogen atom. As the arylene group which may have a substituent, a phenylene group and a tolylene group are preferable, and a phenylene group is particularly preferable. Examples of the substituent of the arylene group include an alkyl group having 1 to 4 carbon atoms or an alkoxy group. Examples of the halogen atom include a fluorine atom, an iodine atom, a chlorine atom, and a bromine atom.

  The amine compound mixture obtained by reacting these amine compounds represented by the general formula (2) with two or more types of halogenated aryl compounds represented by the general formula (3) 2) Even if there is only one amine compound represented by 2), when the type of the aryl halide compound represented by the general formula (3) increases, the type of the amine compound mixture increases rapidly, Since it becomes difficult to adjust the amount, it is preferable to use two kinds of halogenated aryl compounds represented by the general formula (3).

  The present invention is characterized in that at least one amine compound satisfying the formula (1) and one amine compound satisfying the formula (2) are used in combination. May be. In that case, when the content (mass%) of the amine compound that satisfies the formulas (1) and (2) is X1 and X2, respectively, X1 and X2 satisfy the following formulas (3) to (5) Is preferred.

Formula (3) 30 ≦ X1 + X2 <100
Formula (4) 20 <= X1 <= 95
Formula (5) 5 <= X2 <= 45
That is, the main component is preferably 20% by mass or more, and if it is less than 20% by mass, the stability of the coating solution may be deteriorated. The total of the main component and the second main component is preferably 30% by mass or more. By selecting the quantitative ratio of the halogenated arylamine compound and the reaction conditions during the synthesis, the content of the amine compound mixture can be prepared so as to satisfy the above formulas (3) to (5). Moreover, it can also prepare so that said formula (3)-(5) may be satisfy | filled by preparative chromatography. Moreover, the amine compound which satisfy | fills said Formula (1) is synthesize | combined separately separately, and this can also be prepared so that said Formula (3)-(5) may be satisfy | filled.

  In addition, a charge transport material other than these amine compound mixtures can be used in combination, but usually only an amine compound satisfying formula (1), an amine compound satisfying formula (2), and a compound by-produced during synthesis are used. .

  Hereinafter, although the specific example of the amine compound mixture of this invention is shown, this invention is not limited to these.

  When one amine compound represented by the general formula (2) is reacted with two halogenated aryl compounds represented by the general formula (3), a mixture of six amine compounds is generally obtained. . By the arrangement | sequence (Formula 4, Formula 5) of the said compound, it shows that the amine compound mixture C-1 is a mixture of the amine compounds 1-6 of the same row, for example.

  The content of each amine compound in the amine compound mixture can be changed by adjusting the molar ratio of the two halogenated aryl compounds represented by the general formula (3) at the time of synthesis. Table 2 shows the content (% by mass) of each amine compound 1 to 6 in the amine compound mixture synthesized by changing the molar ratio of the halogenated aryl compound at three levels.

  In Table 2, for example, the amine compound mixture C-1-1 is obtained by synthesizing two kinds of halogenated aryl compounds at an equimolar ratio. 6 is a mixture. The amine compound mixtures C-1-2 and C-1-2 were synthesized by changing the molar ratio of the two kinds of halogenated aryl compounds. In this case, the amine compound 1 or 2 was not synthesized. Show.

  The amine compound content (% by mass) of the amine compound mixture was determined from the area ratio of the following high performance liquid chromatography. In the present invention, the area ratio of each component measured under the following conditions is defined as mass%. The measuring device, column, and mobile phase may be changed as long as the mixture can be clearly separated.

  The measurement conditions for high performance liquid chromatography are as follows.

Measuring instrument (high performance liquid chromatography): Hitachi L-2000 series 3D system (manufactured by Hitachi High-Technologies Corporation)
Column: CLC-ODS (manufactured by Shimadzu Corporation)
Detection wavelength: 290 nm
Mobile phase: methanol / tetrahydrofuran = 3/1
Mobile phase flow rate: 1 ml / min
Examples of the amine compound (A-1 to 10) and the halogenated aryl compound (H-1 to 22) used for the synthesis of the amine compound mixture of the present invention are shown below.

<< Synthesis of amine compound mixture >>
Synthesis Example 1 (Synthesis of C-1-1)
The amine compound mixture C-1-1 of the present invention was synthesized according to the following reaction formula.

  A 200 ml 4-head Kolben was fitted with a cooling tube, thermometer, nitrogen introduction tube, and calcium chloride tube, a magnetic stirrer was set, the inside of the system was decompressed, and nitrogen substitution was completely performed. The Kolben was brought to 50 ° C., 0.3 g of palladium acetate and 1.09 g of tri-tert-butylphosphine were added under nitrogen flow, and the mixture was stirred at 50 ° C. until a brown homogeneous system was obtained. To this, 54 ml of dehydrated toluene was added, and (a) 3.0 g, (b) 4.62 g, (c) 4.62 g and 5.19 g of tert-butoxy sodium were added.

  This was heated to reflux and reacted for 5 hours. When the internal temperature dropped to room temperature, 25 ml of water, 25 ml of tetrahydrofuran and 5 g of diatomaceous earth were added and filtered. The filtrate was washed with water until neutral, dried and concentrated. This was separated and purified by column chromatography using a developing solvent of hexane / toluene (volume ratio 4/1) to obtain 6.6 g of the target product C-1-1. Individual compounds were identified by mass spectrometry of samples collected by high performance liquid chromatography.

  The amine compound content (mass%) of the amine compound mixture C-1-1 was determined from the area ratio of the high performance liquid chromatogram (FIG. 4). In FIG. 4, peak 5 represents amine compound 6 of the above-described compound sequence (Chemical Formula 4), peak 6 represents amine compound 5, peak 7 represents amine compound 3 + 4, peak 8 represents amine compound 2, and peak 9 represents amine compound 15. Since peak 7 overlaps with amine compounds 3 and 4, they were separated and quantified by changing the measurement conditions of high performance liquid chromatography. As a result of the measurement, as shown in Table 2, amine compound 1 (7% by mass), amine compound 2 (25% by mass), amine compound 3 (18% by mass), amine compound 4 (18% by mass), amine compound 5 It was an amine compound mixture consisting of (25% by mass) and amine compound 6 (7% by mass).

Synthesis Example 2 (Synthesis of C-10-3)
The amine compound mixture C-10-3 of the present invention was synthesized according to the following reaction formula.

  A cooling tube, a thermometer, a nitrogen introduction tube, and a calcium chloride tube were attached to a 300 ml four-head Kolben, a magnetic stirrer was set, the inside of the system was decompressed, and nitrogen substitution was completely performed. The Kolben was brought to 50 ° C., 0.36 g of palladium acetate and 1.29 g of tri-tert-butylphosphine were added under nitrogen flow, and the mixture was stirred at 50 ° C. until a brown homogeneous system was obtained. To this, 54 ml of dehydrated toluene was added, and (d) 3.0 g, (e) 7.62 g, (f) 1.90 g and 6.12 g of tert-butoxy sodium were added.

  This was heated to reflux and reacted for 5 hours. When the internal temperature dropped to room temperature, 25 ml of water, 25 ml of tetrahydrofuran and 5 g of diatomaceous earth were added and filtered. The filtrate was washed with water until neutral, dried and concentrated. This was separated and purified by column chromatography using a developing solvent of hexane / toluene (4/1) to obtain 6.2 g of the target product, C-10-3.

  Other exemplary compounds can be synthesized in the same manner.

<Photoconductor>
In the photoreceptor of the present invention, in the general formula (1), Ar _{1 to} Ar ₄ are charged with an amine compound containing the amine compound satisfying the formula (1) and the amine compound satisfying the formula (2). Photoconductors contained as a transport material, the structure of the photoconductor containing these charge transport materials will be described below.

  In the present invention, the photoconductor means a photoconductor constituted by providing an organic compound with at least one of a charge generation function and a charge transport function that are indispensable for the constitution of the photoconductor. It includes all known photoreceptors such as a photoreceptor composed of a charge transport material, a photoreceptor composed of a polymer complex with a charge generation function and a charge transport function.

The configuration of the photoreceptor of the present invention is not particularly limited as long as it contains the amine compound mixture (charge transport material) of the present invention, and examples thereof include the following configurations:
1) A structure in which a charge generation layer and a charge transport layer are sequentially laminated as a photosensitive layer on a conductive support;
2) A structure in which a charge generation layer, a first charge transport layer, and a second charge transport layer are sequentially laminated as a photosensitive layer on a conductive support;
3) A structure in which a single layer containing a charge transport material and a charge generation material is formed as a photosensitive layer on a conductive support;
4) A structure in which a charge transport layer and a charge generation layer are sequentially laminated as a photosensitive layer on a conductive support;
5) A structure in which a surface protective layer is further formed on the photosensitive layer of the photoreceptors 1) to 5) above.

  The photoconductor may have any of the above configurations. The surface layer of the photoreceptor is a layer in contact with the air interface. When only a single-layer photosensitive layer is formed on the conductive support, the photosensitive layer is the surface layer, and the conductive layer In the case where a single layer type or laminated type photosensitive layer and a surface protective layer are laminated on the conductive support, the surface protective layer is the outermost surface layer. In the present invention, the configuration 2) is most preferably used. Note that, regardless of the configuration of the photoreceptor of the present invention, an undercoat layer (intermediate layer) may be formed on the conductive support prior to the formation of the photosensitive layer.

  The charge transport layer means a layer having a function of transporting charge carriers generated in the charge generation layer by photoexposure to the surface of the photoreceptor, and the specific detection of the charge transport function is performed by the charge generation layer and the charge transport layer. It can be confirmed by laminating the layer on a conductive support and detecting the optical conductivity.

  Next, the layer structure of the photoreceptor will be described focusing on the structure 1).

(Conductive support)
The conductive support used for the photoreceptor may be either a sheet or a cylinder, but a cylindrical conductive support is preferred for designing an image forming apparatus in a compact manner.

  Cylindrical conductive support means a cylindrical support necessary for forming an endless image by rotating. Conductivity is within a range of 0.1 mm or less in straightness and 0.1 mm or less in deflection. These supports are preferred. Exceeding the range of straightness and shake makes it difficult to form a good image.

As the conductive material, a metal drum such as aluminum or nickel, a plastic drum deposited with aluminum, tin oxide, indium oxide, or the like, or a paper / plastic drum coated with a conductive substance can be used. The conductive support preferably has a specific resistance of 10 ³ Ωcm or less at room temperature. As the conductive support used in the present invention, an aluminum support is most preferable. As the aluminum support, one in which components such as manganese, zinc, magnesium and the like are mixed in addition to the main component aluminum is also used.

(Middle layer)
In the present invention, it is preferable to provide an intermediate layer between the conductive support and the photosensitive layer.

  The intermediate layer used in the present invention preferably contains N-type semiconductor particles. The N-type semiconductive particle means a particle whose main charge carrier is an electron. That is, since the main charge carriers are electrons, the intermediate layer containing the N-type semiconductive particles in the insulating binder effectively blocks hole injection from the substrate, and the electrons from the photosensitive layer. In contrast, it has a property of low blocking.

As the N-type semiconductor particles, titanium oxide (TiO ₂ ) and zinc oxide (ZnO) are preferable, and titanium oxide is particularly preferably used.

  As the N-type semiconductor particles, fine particles having a number average primary particle size in the range of 3.0 to 200 nm are used. In particular, 5 to 100 nm is preferable. The number average primary particle diameter is a measured value as an average diameter in the ferret direction by observing 100 particles as primary particles at random by magnifying the fine particles 10,000 times by transmission electron microscope observation and image analysis. N-type semiconducting particles having a number average primary particle size of less than 3.0 nm are difficult to uniformly disperse in the intermediate layer binder, and easily form aggregated particles. Is likely to occur. On the other hand, N-type semiconducting particles having a number average primary particle size larger than 200 nm tend to make large irregularities on the surface of the intermediate layer, and the dot image tends to deteriorate through these large irregularities. In addition, the N-type semiconductive particles having a number average primary particle size larger than 200 nm are likely to precipitate in the dispersion and easily generate aggregates. As a result, the dot image tends to deteriorate.

  The titanium oxide particles have anatase, rutile, brookite, and amorphous forms as crystal forms. Among them, the rutile form titanium oxide pigment or the anatase form titanium oxide pigment has a rectifying property of charge passing through the intermediate layer. In other words, the mobility of electrons is increased, the charging potential is stabilized, the residual potential is prevented from increasing, and the dot image is prevented from deteriorating, which is most preferable as the N-type semiconductor particles of the present invention. .

  N-type semiconductive particles are preferably surface-treated with a polymer containing methylhydrogensiloxane units. The molecular weight of the polymer containing the methyl hydrogen siloxane unit is 1000 to 20000, and the surface treatment effect is high. As a result, the rectifying property of the N-type semiconductor particles is improved, and the N-type semiconductor particles are contained. By using the intermediate layer, the occurrence of black spots is prevented, and an excellent dot image reproducibility is obtained.

The polymer containing methylhydrogensiloxane units _{- (HSi (CH 3) O} ) - a copolymer of structural units and other structural units (that of the other siloxane units) are preferred. As other siloxane units, dimethylsiloxane units, methylethylsiloxane units, methylphenylsiloxane units, diethylsiloxane units, and the like are preferable, and dimethylsiloxane is particularly preferable. The proportion of methylhydrogensiloxane units in the copolymer is 10 to 99 mol%, preferably 20 to 90 mol%.

  The methylhydrogensiloxane copolymer may be any of a random copolymer, a block copolymer, a graft copolymer, etc., but a random copolymer and a block copolymer are preferred. In addition to methyl hydrogen siloxane, the copolymer component may be one component or two or more components.

  The intermediate layer coating solution prepared for forming the intermediate layer used in the present invention is composed of a binder resin, a dispersion solvent and the like in addition to the N-type semiconductive particles such as the surface-treated titanium oxide.

  The ratio of the N-type semiconductive particles in the intermediate layer is preferably 1.0 to 2.0 times in terms of the volume ratio of the intermediate layer to the binder resin (when the volume of the binder resin is 1). By using the N-type semiconducting particles of the present invention at such a high density in the intermediate layer, the rectification of the intermediate layer is enhanced, and the increase in residual potential and dot image degradation are effective even when the film thickness is increased. Therefore, a good photoreceptor can be formed. In addition, such an intermediate layer preferably uses 100 to 200 parts by volume of N-type semiconductive particles with respect to 100 parts by volume of the binder resin.

  On the other hand, as the binder resin in which these particles are dispersed to form the layer structure of the intermediate layer, a polyamide resin is preferable in order to obtain good dispersibility of the particles, but the polyamide resin shown below is particularly preferable.

  The binder resin for the intermediate layer is preferably an alcohol-soluble polyamide resin. As the binder resin for the intermediate layer of the photoreceptor, a resin having excellent solvent solubility is required in order to form the intermediate layer with a uniform film thickness. As such an alcohol-soluble polyamide resin, a copolymerized polyamide resin or a methoxymethylated polyamide resin composed of a chemical structure with few carbon chains between amide bonds such as 6-nylon described above is known. In addition to these resins, polyamide resins having the following chemical structure are preferably used.

  The molecular weight of the polyamide resin is preferably 5,000 to 80,000, more preferably 10,000 to 60,000 in terms of number average molecular weight. When the number average molecular weight is 5,000 or less, the uniformity of the film thickness of the intermediate layer is deteriorated, and the effects of the present invention are not sufficiently exhibited. On the other hand, if it is larger than 80,000, the solvent solubility of the resin is likely to be reduced, and an agglomerated resin is likely to be generated in the intermediate layer, which tends to cause black spots and deterioration of the dot image.

  A part of the polyamide resin is already available on the market. For example, the polyamide resin is sold under the trade names such as Vestamelt X1010 and X4685 manufactured by Daicel Degussa Co., Ltd., and can be produced by a general synthesis method of polyamide. However, an example of a synthesis example is given below.

  As the solvent for dissolving the polyamide resin and preparing the coating solution, alcohols having 2 to 4 carbon atoms such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol are preferable, It is excellent in the solubility of polyamide and the coating property of the prepared coating solution. These solvents are 30 to 100% by mass, preferably 40 to 100% by mass, and more preferably 50 to 100% by mass in the total solvent. Examples of co-solvents that can be used in combination with the above-mentioned solvent to obtain preferable effects include methanol, benzyl alcohol, toluene, methylene chloride, cyclohexanone, and tetrahydrofuran.

  The thickness of the intermediate layer is preferably 0.3 to 10 μm. If the film thickness is less than 0.5 μm, black spots or the like are likely to occur, and the dot image is likely to deteriorate. If it exceeds 10 μm, the residual potential is likely to increase, and the dot image tends to deteriorate. As for the film thickness of an intermediate | middle layer, 0.5-5 micrometers is more preferable.

Moreover, it is preferable that the said intermediate | middle layer is an insulating layer substantially. Here, the insulating layer has a volume resistance of 1 × 10 ⁸ Ω · cm or more. The volume resistance of the intermediate layer and the protective layer of the present invention is preferably 1 × 10 ⁸ to 10 ¹⁵ Ω · cm, more preferably 1 × 10 ⁹ to 10 ¹⁴ Ω · cm, and further preferably 2 × 10 ⁹ to 1 ×. 10 ¹³ Ω · cm. The volume resistance can be measured as follows.

  Measurement conditions: According to JIS: C2318-1975.

Measuring instrument: Hiresta IP manufactured by Mitsubishi Yuka
Measurement conditions: Measurement probe HRS
Applied voltage: 500V
Measurement environment: 30 ± 2 ℃, 80 ± 5RH%
When the volume resistance is less than 1 × 10 ⁸ Ω · cm, the charge blocking property of the intermediate layer decreases, the occurrence of black spots increases, the potential holding property of the photoreceptor deteriorates, and good image quality cannot be obtained. On the other hand, if it is greater than 1 × 10 ¹⁵ Ω · cm, the residual potential tends to increase in repeated image formation, and good image quality cannot be obtained.

(Photosensitive layer)
The photosensitive layer configuration of the photoreceptor of the present invention may be a single layer photosensitive layer configuration in which a charge generation function and a charge transport function are provided on one layer on the intermediate layer, but more preferably the function of the photosensitive layer. It is preferable that the charge generation layer (CGL) and the charge transport layer (CTL) be separated. By adopting a configuration in which the functions are separated, an increase in the residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negatively charged photoconductor, it is preferable that a charge generation layer (CGL) is formed on the intermediate layer, and a charge transport layer (CTL) is formed thereon.

  The structure of the photosensitive layer of the function-separated negatively charged photoreceptor will be described below.

(Charge generation layer)
In the photoreceptor of the present invention, it is preferable to use a charge generating material having high sensitivity characteristics in the wavelength region of 350 to 500 nm as the charge generating material. In the present invention, as such a charge generating substance, a phthalocyanine compound, a perylene compound, a polycyclic quinone compound, an azo compound, or the like is preferably used. Moreover, these compounds can be used in combination.

  Examples of phthalocyanine compounds include titanyl phthalocyanine pigments having high sensitivity to long wavelength LEDs and laser light, for example, gallium phthalocyanines such as hydroxygallium phthalocyanine (Japanese Patent Laid-Open No. 5-263007), chlorogallium phthalocyanine, and X-ray diffraction. A type titanyl phthalocyanine (JP-A-62-97064) having a maximum peak at 26.3 degrees in the spectrum (acceptable range of ± 0.2 degrees), characteristic peaks at 7.6 and 28.6 degrees B-type titanyl phthalocyanine (JP-A 61-239248), Y-type titanyl phthalocyanine having a maximum peak at 27.3 degrees (JP-A 3-35245) and 2,3-butane having stereoregularity Titanyl phthalocyanine adduct of diol (Japanese Patent Application Laid-Open No. 8-822942), etc. The to titanyl phthalocyanines known can be used. Among these, Y-type titanyl phthalocyanine (y-TiOPc) is preferable.

  Examples of the charge generation material include compounds shown below.

  In the present invention, a phthalocyanine compound, a polycyclic quinone compound or an azo compound is preferable. These compounds have a crystal structure capable of forming a stable aggregate structure between a plurality of molecules, and are hardly deteriorated by repeated use, and can increase the residual potential.

  When a binder is used as the CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferred resins include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, phenoxy resin, and the like. Can be mentioned. The ratio of the binder resin to the charge generating material is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential associated with repeated use can be minimized. The thickness of the charge generation layer is preferably from 0.3 to 2 μm.

(Charge transport layer)
The charge transport layer contains a charge transport material (CTM) and a binder resin. As other substances, an additive such as an antioxidant may be contained in addition to the inorganic fine particles as necessary.

  As the charge transport material (CTM), the charge transport materials represented by the general formula (1) and the general formula (2) are used. In addition, a known hole transport property (P-type) charge transport is used. A substance (CTM) may be used in combination. For example, a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, a butadiene compound, or the like can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer.

  The binder resin used for the charge transport layer (CTL) may be either a thermoplastic resin or a thermosetting resin. For example, polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, and these resins A copolymer resin containing two or more of the repeating unit structures. In addition to these insulating resins, polymer organic semiconductors such as poly-N-vinylcarbazole can be used. Of these, polycarbonate resins are most preferred because of their low water absorption and good CTM dispersibility and electrophotographic characteristics.

  The ratio of the binder resin to the charge transport material is preferably 50 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

  The total thickness of the charge transport layer is preferably 10 to 25 μm. When the total film thickness is less than 10 μm, it is difficult to sufficiently obtain the latent image potential during development, and image density is lowered and dot reproducibility is liable to be deteriorated. Diffusion of charge carriers generated in the generation layer) increases, and dot reproducibility tends to deteriorate. Further, the thickness of the charge transport layer serving as the surface layer is preferably 1.0 to 8.0 μm.

  Solvents or dispersion media used for forming intermediate layers, charge generation layers, charge transport layers and the like include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone , Methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, Tetrachloroethane, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl Cellosolve, and the like. Although this invention is not limited to these, Solvents friendly to global environment, such as tetrahydrofuran and methyl ethyl ketone, are used preferably. These solvents can be used alone or as a mixed solvent of two or more.

  Next, as a coating processing method for manufacturing the photoreceptor, a coating processing method such as dip coating or spray coating is used in addition to the slide hopper type coating device. It is most preferable to use a circular slide hopper type coating apparatus for forming the surface layer.

  Among the above coating liquid supply type coating apparatuses, the coating method using a slide hopper type coating apparatus is most suitable when the above-described dispersion using a low boiling point solvent is used as the coating liquid, and is a cylindrical photoconductor. In this case, the coating is preferably performed using a circular slide hopper type coating apparatus described in detail in JP-A No. 58-189061 and the like.

  In the coating method using a circular slide hopper type coating apparatus, the slide surface end and the base material are arranged with a certain gap (about 2 μm to 2 mm), so that the base material is not damaged, and layers having different properties are multilayered. Even in the case of forming, it can be applied without damaging the already applied layer. Furthermore, when multiple layers with different properties and dissolved in the same solvent are formed, the time in the solvent is much shorter than in the dip coating method, so that the lower layer component hardly elutes to the upper layer side, and the coating tank Therefore, it can be applied without deteriorating the dispersibility of the inorganic fine particles.

  The surface layer of the photoreceptor of the present invention preferably contains an antioxidant. The surface layer is easily oxidized by an active gas such as NOx or ozone when the photosensitive member is charged, and image blur is likely to occur. However, the presence of an antioxidant can prevent the occurrence of image blur. Typical examples of the antioxidants prevent or suppress the action of oxygen on auto-oxidizing substances existing in the photoreceptor or on the photoreceptor surface under conditions of light, heat, discharge, etc. It is a substance with properties. Typical examples include the following compound groups.

  Solvents or dispersion media used for forming intermediate layers, charge generation layers, charge transport layers and the like include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone , Methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, Tetrachloroethane, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl Cellosolve, and the like. Although this invention is not limited to these, Dichloromethane, 1, 2- dichloroethane, methyl ethyl ketone, etc. are used preferably. These solvents can be used alone or as a mixed solvent of two or more.

  Next, an image forming apparatus using the photoreceptor of the present invention will be described.

  An image forming apparatus 1 shown in FIG. 1 is a digital image forming apparatus, and includes an image reading unit A, an image processing unit B, an image forming unit C, and a transfer paper transport unit D as a transfer paper transport unit. Yes.

  An automatic document feeder that automatically conveys the document is provided above the image reading unit A. The document placed on the document table 11 is separated and conveyed by the document conveyance roller 12 to the reading position 13a. The image is read. The document after the document reading is completed is discharged onto the document discharge tray 14 by the document transport roller 12.

  On the other hand, the image of the original when placed on the platen glass 13 is read at a speed v of the first mirror unit 15 including the illumination lamp and the first mirror constituting the scanning optical system, and the V-shaped first image is located. Reading is performed by the movement of the second mirror unit 16 including the two mirrors and the third mirror in the same direction at the speed v / 2.

  The read image is formed on the light receiving surface of the image sensor CCD, which is a line sensor, through the projection lens 17. The line-shaped optical image formed on the image sensor CCD is sequentially photoelectrically converted into an electric signal (luminance signal) and then A / D converted, and the image processing unit B performs processing such as density conversion and filter processing. Then, the image data is temporarily stored in the memory.

  In the image forming unit C, as an image forming unit, a drum-shaped photoconductor 21 as an image carrier, a charging means (charging step) 22 for charging the photoconductor 21 on the outer periphery thereof, and a surface potential of the charged photoconductor. Potential detecting means 220 for detecting the toner, developing means (developing process) 23, transfer conveying belt device 45 as a transferring means (transfer process), cleaning device (cleaning process) 26 for the photosensitive member 21, and light neutralizing means (light slow charge). PCL (precharge lamp) 27 as a process is arranged in the order of operation. Further, on the downstream side of the developing means 23, a reflection density detecting means 222 for measuring the reflection density of the patch image developed on the photosensitive member 21 is provided. The photosensitive member 21 of the present invention is used as the photosensitive member 21 and is rotated in the clockwise direction shown in the figure.

  After the rotating photosensitive member 21 is uniformly charged by the charging unit 22, an image based on an image signal called from the memory of the image processing unit B by an exposure optical system as an image exposure unit (image exposure step) 30 is used. Exposure is performed. The exposure optical system as the image exposure means 30 as the writing means uses a laser diode (not shown) as a light source, and the optical path is bent by the reflection mirror 32 via the rotating polygon mirror 31, the fθ lens 34, and the cylindrical lens 35, and main scanning is performed. Therefore, image exposure is performed on the photoconductor 21 at the position Ao, and an electrostatic latent image is formed by rotation (sub-scanning) of the photoconductor 21. In one example of the present embodiment, the character portion is exposed to form an electrostatic latent image.

  In the image forming apparatus of the present invention, when forming an electrostatic latent image on a photoreceptor, a semiconductor laser or light emitting diode having an oscillation wavelength of 350 to 500 nm is used as an image exposure light source. By using these image exposure light sources, the exposure dot diameter in the writing principal direction is narrowed down to 10 to 50 μm, and digital exposure is performed on the photosensitive member, whereby 600 dpi (dpi: the number of dots per 2.54 cm) or more and 2500 dpi. High-resolution electrophotographic images can be obtained.

The exposure dot diameter refers to the length of the exposure beam (Ld: measured at the maximum position) along the main scanning direction in a region where the intensity of the exposure beam is 1 / e ² or more of the peak intensity.

The light beams used have a solid scanner such as the scanning optical system and LED using a semiconductor laser, there is a Gaussian distribution and Lorentz distribution, etc. also the light intensity distribution is in each 1 / e ² or more regions of peak intensity The exposure dot diameter according to the present invention is used.

  The electrostatic latent image on the photoconductor 21 is reversely developed by the developing unit 23, and a visible toner image is formed on the surface of the photoconductor 21. In the image forming method of the present invention, it is preferable to use a polymerized toner as a developer used in the developing means. By using a polymer toner having a uniform shape and particle size distribution in combination with the photoreceptor of the present invention, an electrophotographic image with better sharpness can be obtained.

  In the transfer paper transport section D, paper feed units 41 (A), 41 (B), and 41 (C) are provided below the image forming unit as transfer paper storage means for storing transfer paper P of different sizes. A manual paper feeding unit 42 that performs manual paper feeding is provided on the side of the photoconductor, and the transfer paper P selected from any of them is fed along the transport path 40 by the guide roller 43 and fed. The transfer paper P is temporarily stopped by a pair of paper feed registration rollers 44 that correct the inclination and bias of the transfer paper P to be transferred, and then re-feeded. The transport path 40, the pre-transfer roller 43a, and the paper feed While being guided by the path 46 and the entrance guide plate 47, the toner image on the photosensitive member 21 is placed and conveyed on the transfer conveyance belt 454 of the transfer conveyance belt device 45 by the transfer pole 24 and the separation pole 25 at the transfer position Bo. Transcribed, transfer sheet P is separated from the photosensitive member 21 surface, it is conveyed to the fixing unit 50 by the transfer conveyor belt device 45.

  The fixing unit 50 includes a fixing roller 51 and a pressure roller 52. By passing the transfer paper P between the fixing roller 51 and the pressure roller 52, the toner is fixed by heating and pressing. After the toner image has been fixed, the transfer paper P is discharged onto the paper discharge tray 64.

  The above describes the state in which image formation is performed on one side of the transfer paper. However, in the case of double-sided copying, the paper discharge switching member 170 is switched, the transfer paper guide 177 is opened, and the transfer paper P is indicated by a broken arrow. Conveyed in the direction.

  Further, the transfer paper P is transported downward by the transport mechanism 178 and is switched back by the transfer paper reversing unit 179, and the rear end portion of the transfer paper P is transported into the duplex copying paper supply unit 130 as the leading end. The

  The transfer paper P is moved in a paper feed direction by a conveyance guide 131 provided in the double-sided copy paper supply unit 130, the transfer paper P is re-fed by the paper supply roller 132, and the transfer paper P is guided to the conveyance path 40. .

  Again, as described above, the transfer paper P is conveyed in the direction of the photosensitive member 21, the toner image is transferred to the back surface of the transfer paper P, fixed by the fixing unit 50, and then discharged onto the paper discharge tray 64.

  The image forming apparatus of the present invention is configured by integrally combining the above-described photosensitive member and components such as a developing device and a cleaning device as a process cartridge, and this unit is configured to be detachable from the apparatus main body. Also good. In addition, at least one of a charger, an image exposure device, a developing device, a transfer or separation device, and a cleaning device is integrally supported together with a photosensitive member to form a process cartridge, and is a single unit that is detachable from the apparatus main body. It is good also as a structure which can be attached or detached using guide means, such as a rail of an apparatus main body.

  FIG. 2 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention.

  This color image forming apparatus is called a tandem type color image forming apparatus, and includes four sets of image forming units (image forming units) 10Y, 10M, 10C, and 10Bk, an endless belt-shaped intermediate transfer body unit 7, and a feeding unit. It comprises a paper conveying means 21 and a fixing means 24. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

  The image forming unit 10Y that forms a yellow image includes a charging unit (charging step) 2Y, an exposure unit (exposure step) 3Y, and a developing unit disposed around a drum-shaped photoconductor 1Y as a first image carrier. A unit (developing step) 4Y, a primary transfer roller 5Y as a primary transfer unit (primary transfer step), and a cleaning unit 6Y. An image forming unit 10M that forms a magenta image includes a drum-shaped photosensitive member 1M as a first image carrier, a charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer roller 5M as a primary transfer unit, It has a cleaning means 6M. An image forming unit 10C for forming a cyan image includes a drum-shaped photoreceptor 1C as a first image carrier, a charging unit 2C, an exposure unit 3C, a developing unit 4C, and a primary transfer roller 5C as a primary transfer unit. It has cleaning means 6C. The image forming unit 10Bk that forms a black image includes a drum-shaped photoreceptor 1Bk as a first image carrier, a charging unit 2Bk, an exposure unit 3Bk, a developing unit 4Bk, a primary transfer roller 5Bk as a primary transfer unit, and a cleaning unit. 6Bk.

  The four sets of image forming units 10Y, 10M, 10C, and 10Bk include charging means 2Y, 2M, 2C, and 2Bk that rotate around the photosensitive drums 1Y, 1M, 1C, and 1Bk, and image exposure means 3Y, 3M, 3C and 3Bk, rotating developing means 4Y, 4M, 4C and 4Bk, and cleaning means 5Y, 5M, 5C and 5Bk for cleaning the photosensitive drums 1Y, 1M, 1C and 1Bk.

  The image forming units 10Y, 10M, 10C, and 10Bk have the same configuration except that the colors of toner images formed on the photoreceptors 1Y, 1M, 1C, and 1Bk are different, and the image forming unit 10Y is taken as an example in detail. explain.

  The image forming unit 10Y has a charging unit 2Y (hereinafter simply referred to as a charging unit 2Y or a charger 2Y), an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 5Y (around a photosensitive drum 1Y as an image forming body). Hereinafter, the cleaning means 5Y or the cleaning blade 5Y) is simply disposed, and a yellow (Y) toner image is formed on the photosensitive drum 1Y. In the present embodiment, in the image forming unit 10Y, at least the photosensitive drum 1Y, the charging unit 2Y, the developing unit 4Y, and the cleaning unit 5Y are provided so as to be integrated.

  The charging unit 2Y is a unit that applies a uniform potential to the photosensitive drum 1Y. In the present embodiment, a corona discharge type charger 2Y is used for the photosensitive drum 1Y.

  The image exposure means 3Y performs exposure based on the image signal (yellow) on the photosensitive drum 1Y given a uniform potential by the charger 2Y, and forms an electrostatic latent image corresponding to the yellow image. As the exposure means 3Y, the exposure means 3Y includes an LED in which light emitting elements are arranged in an array in the axial direction of the photosensitive drum 1Y and an imaging element (trade name; Selfoc lens), or A laser optical system or the like is used.

  The image forming apparatus of the present invention is configured by integrally combining the above-described photosensitive member and components such as a developing device and a cleaning device as a process cartridge (image forming unit), and this image forming unit is connected to the apparatus main body. It may be configured to be detachable. Further, at least one of a charger, an image exposure device, a developing device, a transfer or separation device, and a cleaning device is integrally supported together with a photosensitive member to form a process cartridge (image forming unit), which is detachable from the apparatus main body. A single image forming unit may be detachable using guide means such as a rail of the apparatus main body.

  The endless belt-like intermediate transfer body unit 7 includes an endless belt-like intermediate transfer body 70 as a second image carrier having a semiconductive endless belt shape that is wound around a plurality of rollers and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10Bk is sequentially transferred onto a rotating endless belt-shaped intermediate transfer body 70 by primary transfer rollers 5Y, 5M, 5C, and 5Bk as primary transfer means. Thus, a synthesized color image is formed. A transfer material P as a transfer material (a support for carrying a fixed final image: for example, plain paper, a transparent sheet, etc.) housed in the paper feed cassette 20 is fed by a paper feed means 21 and a plurality of intermediates. After passing through rollers 22A, 22B, 22C, 22D and registration roller 23, they are conveyed to a secondary transfer roller 5b as a secondary transfer means, and are secondarily transferred onto a transfer material P to transfer a color image all at once. The transfer material P onto which the color image has been transferred is subjected to fixing processing by the fixing unit 24, is sandwiched between paper discharge rollers 25, and is placed on a paper discharge tray 26 outside the apparatus. Here, a transfer support for a toner image formed on a photosensitive member such as an intermediate transfer member or a transfer material is collectively referred to as a transfer medium.

  On the other hand, after the color image is transferred to the transfer material P by the secondary transfer roller 5b as the secondary transfer means, the residual toner is removed by the cleaning means 6b from the endless belt-shaped intermediate transfer body 70 in which the transfer material P is separated by curvature. The

  During the image forming process, the primary transfer roller 5Bk is always in contact with the photoreceptor 1Bk. The other primary transfer rollers 5Y, 5M, and 5C are in contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5b contacts the endless belt-shaped intermediate transfer body 70 only when the transfer material P passes through the secondary transfer roller 5b.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10Bk and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10Bk are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1Bk in the drawing. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 73, 74, primary transfer rollers 5Y, 5M, 5C, 5Bk, and cleaning means 6b. Consists of.

  Next, FIG. 3 shows a color image forming apparatus using the photoreceptor of the present invention (a copying machine having at least a charging means, an exposure means, a plurality of developing means, a transfer means, a cleaning means and an intermediate transfer body around the photoreceptor. It is a cross-sectional view of the configuration of a laser beam printer. The belt-shaped intermediate transfer body 70 uses an elastic body having a medium resistance.

  Reference numeral 1 denotes a rotary drum type photoconductor that is repeatedly used as an image forming body, and is rotationally driven in a counterclockwise direction indicated by an arrow at a predetermined peripheral speed.

  In the rotation process, the photoreceptor 1 is uniformly charged to a predetermined polarity and potential by a charging means (charging process) 2, and then time-series electric digital of image information by an image exposure means (image exposure process) 3 (not shown). An electrostatic latent image corresponding to the yellow (Y) color component image (color information) of the target color image is formed by receiving image exposure by scanning exposure light or the like by a laser beam modulated in accordance with the pixel signal. The

  Then, the electrostatic latent image is developed with yellow toner as the first color by yellow (Y) developing means: developing step (yellow color developing device) 4Y. At this time, the second to fourth developing means (magenta developer, cyan developer, black developer) 4M, 4C, and 4Bk are turned off and do not act on the photosensitive member 1. The first color yellow toner image is not affected by the second to fourth developing units.

  The intermediate transfer member 70 is stretched by rollers 79a, 79b, 79c, 79d, and 79e, and is driven to rotate in the clockwise direction at the same peripheral speed as the photosensitive member 1.

  The yellow toner image of the first color formed and supported on the photosensitive member 1 is applied to the intermediate transfer member 70 from the primary transfer roller 5a in the process of passing through the nip portion between the photosensitive member 1 and the intermediate transfer member 70. The intermediate transfer (primary transfer) is sequentially performed on the outer peripheral surface of the intermediate transfer body 70 by the electric field formed by the primary transfer bias.

  The surface of the photosensitive member 1 after the transfer of the first color yellow toner image corresponding to the intermediate transfer member 70 is cleaned by the cleaning device 6a.

  Similarly, the second color magenta toner image, the third color cyan toner image, and the fourth color black (black) toner image are sequentially superimposed and transferred onto the intermediate transfer body 70 to correspond to the target color image. A superimposed color toner image is formed.

  The secondary transfer roller 5b is supported in parallel with the secondary transfer counter roller 79b so as to be separated from the lower surface of the intermediate transfer body 70.

  The primary transfer bias for sequentially superimposing and transferring the first to fourth color toner images from the photosensitive member 1 to the intermediate transfer member 70 has a polarity opposite to that of the toner and is applied from a bias power source. The applied voltage is, for example, in the range of +100 V to +2 kV.

  In the primary transfer process of the first to third color toner images from the photosensitive member 1 to the intermediate transfer member 70, the secondary transfer roller 5b and the intermediate transfer member cleaning means 6b can be separated from the intermediate transfer member 70. .

  When the superimposed color toner image transferred onto the belt-shaped intermediate transfer member 70 is transferred onto the transfer material P, which is the second image carrier, the secondary transfer roller 5b is brought into contact with the belt of the intermediate transfer member 70. At the same time, the transfer material P is fed from the pair of paper registration rollers 23 through the transfer sheet guide to the belt of the intermediate transfer body 70 to the contact nip with the secondary transfer roller 5b at a predetermined timing. A secondary transfer bias is applied to the secondary transfer roller 5b from a bias power source. By this secondary transfer bias, the superimposed color toner image is transferred (secondary transfer) from the intermediate transfer body 70 to the transfer material P as the second image carrier. The transfer material P that has received the transfer of the toner image is introduced into the fixing means 24 and fixed by heating.

  The image forming apparatus of the present invention is generally applicable to electrophotographic apparatuses such as electrophotographic copying machines, laser printers, LED printers, and liquid crystal shutter printers. Further, the display, recording, light printing, plate making and facsimile using the electrophotographic technology are applied. The present invention can be widely applied to such devices.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to this. In the following text, “part” means “part by mass”.

Example 1
<< Production of Photoreceptor 1 >>
Photoreceptor 1 was produced as follows.

[Middle layer]
On the washed cylindrical aluminum substrate (10 points surface roughness Rz: 0.81 μm processed by cutting), the following intermediate layer coating solution was applied by dip coating, dried at 120 ° C. for 30 minutes, and dried film An intermediate layer having a thickness of 5 μm was formed.

(Preparation of intermediate layer coating solution)
The following intermediate layer dispersion was diluted twice with the same mixed solvent, and allowed to stand overnight, then filtered (filter; rigesh mesh filter made by Nihon Pall Corporation, nominal filtration accuracy: 5 microns, pressure: 50 kPa), and the intermediate layer coating solution was Prepared.

(Preparation of intermediate layer dispersion)
Binder resin (Exemplary polyamide N-1) 1 part Rutile-type titanium oxide (primary particle size 35 nm; titanium oxide pigment prepared by surface treatment with dimethylpolysiloxane having a hydroxyl group at the terminal to have a hydrophobicity of 33) 5.6 Part Ethanol / n-propyl alcohol / THF (45/20/30 mass ratio) 10 parts The above components were mixed and dispersed in a batch system for 10 hours using a sand mill disperser to prepare an intermediate layer dispersion. .

[Charge generation layer: CGL]
(Preparation of charge generation layer coating solution)
Charge generation material (CGM): Exemplified compound CGM-1 24 parts Polyvinyl butyral resin (ESREC BL-1: Sekisui Chemical Co., Ltd.) 12 parts 2-butanone / cyclohexanone (4/1 volume ratio) 300 parts The above composition was mixed. Then, the mixture was dispersed using a sand mill to prepare a charge generation layer coating solution.

  This coating solution was applied onto the intermediate layer by a dip coating method to form a charge generation layer having a dry film thickness of 0.5 μm.

[Charge transport layer: CTL]
(Preparation of charge transport layer coating solution)
Charge transport material (Exemplary Compound C-1-1) 225 parts Polycarbonate (Z300: manufactured by Mitsubishi Gas Chemical Company) 300 parts Antioxidant (Exemplary Compound AO-1) 3 parts Tetrahydrofuran / Toluene (4/1 volume ratio) 2000 parts Silicon oil (KF-54: manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part The above components were mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method and dried at 110 ° C. for 70 minutes to form a charge transport layer having a dry film thickness of 20.0 μm.

<< Preparation of photoconductors 2-15 >>
Photoconductors 2 to 15 were prepared in the same manner as the photoconductor 1 except that the type of the charge transport material in the charge transport layer was changed as shown in Table 2 in the production of the photoconductor 1. CR-1 used for the photoreceptor 15 is a charge transport material of the following benzidine compound.

<< Evaluation of photoconductor >>
The produced photoreceptors were evaluated for sensitivity, repeatability, and image evaluation (1 dot line, 2 dot line) as follows.

(sensitivity)
Basically, the digital copying machine Sitoos 7085 (manufactured by Konica Minolta Business Technologies Co., Ltd.) having the configuration shown in FIG. Furthermore, the surface potential of the photoconductor was modified so that it could be measured with a surface potential meter. The amount of light necessary for the measurement was measured, and the sensitivity (E1 / 2) was determined. In addition, dpi represents the number of dots per 2.54 cm.

  Similarly, the sensitivity was measured by changing the exposure light source to a semiconductor laser of 450 nm or 500 nm.

(Repeat characteristics)
Using a remodeling machine (using a 405 nm semiconductor laser) used for sensitivity measurement, the initial dark part potential (Vd) and the initial bright part potential (Vl) are set around −700 V and −200 V, respectively, and charging and exposure are 3000. Repeatedly, the fluctuation amount (ΔVd, ΔVl) of Vd and Vl was measured. Note that minus represents a decrease in potential, and plus represents an increase in potential.

(Image evaluation)
Using a modified machine (using a 405 nm semiconductor laser) used for sensitivity measurement, the photoconductors 1 to 15 were mounted on the copying machine and evaluated. Evaluation items and evaluation criteria are shown below.

<1 dot line>
A one-dot line and a solid black image were created on white A4 paper and evaluated according to the following criteria.

◎: 1 dot line is reproduced continuously, solid image density is 1.2 or more (good)
○: 1 dot line is reproduced continuously, but solid image density is less than 1.2 to 1.0 or more (no problem in practical use)
×: Even if one dot line is cut and reproduced, or one dot line is reproduced continuously, the solid image density is less than 1.0 (there is a problem in practical use)
<2-dot line>
A 2-dot white line was created in a solid black image and evaluated according to the following criteria.

A: A white line of 2 dot lines is reproduced continuously, and the solid image density is 1.2 or more (good).
○: The white line of 2 dot lines is reproduced continuously, but the solid image density is less than 1.2 to 1.0 or more (no problem in practical use)
X: Even if the white line of 2 dot lines is cut and reproduced, or the white line of 2 dot lines is reproduced continuously, the solid image density is less than 1.0 (there is a problem in practical use)
The solid image density was measured by using a relative reflection density of RD-918 manufactured by Macbeth Co., Ltd., with the paper reflection density set to “0”.

  The results of the above evaluation are shown in Table 3.

  As is apparent from Table 3, the photoreceptors 1 to 14 using the amine compound mixture of the present invention as a charge transport material have excellent sensitivity and repeatability with respect to 400 to 500 nm irradiation light such as short wavelength laser light. Even in image evaluation using 450 nm short wavelength laser light, the reproducibility of 1 dot line and 2 dot line is excellent. On the other hand, the photoconductor 15 using the charge transport material of the comparative example is inferior to the photoconductors 1 to 14 of the present invention in the evaluation of sensitivity and repeatability, and the reproducibility of 1 dot line in the image evaluation. Degradation is large.

1 is a schematic view in which functions of an image forming apparatus of the present invention are incorporated. 1 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention. 1 is a cross-sectional view of a color image forming apparatus using a photoconductor of the present invention. It is a high performance liquid chromatogram of the amine compound mixture of the present invention.

Explanation of symbols

10Y, 10M, 10C, 10Bk Image forming unit 1Y, 1M, 1C, 1Bk Photoconductor 2Y, 2M, 2C, 2Bk Charging unit 3Y, 3M, 3C, 3Bk Exposure unit 4Y, 4M, 4C, 4Bk Developing unit

Claims (8)

In the following general formula (1), Ar _{1 to} Ar ₄ contain an amine compound that satisfies the following formula (1) and an amine compound that satisfies the following formula (2).

(In the formula, R ₁ and R ₂ represent an alkyl group or an aryl group, and R ₁ and R ₂ may be linked to form a cyclic structure. Ar ₅ and Ar ₆ may have a substituent. Represents an arylene group.)
Formula (1) Ar ₁ = Ar ₂ = Ar ₃ = Ar ₄
Formula (2) Ar ₁ = Ar ₂ = Ar ₃ ≠ Ar ₄ An amine compound mixture obtained by reacting an amine compound represented by the following general formula (2) with two or more halogenated aryl compounds represented by the following general formula (3).

(In the formula, R ₁ and R ₂ represent an alkyl group or an aryl group, and R ₁ and R ₂ may be linked to form a cyclic structure. Ar ₅ and Ar ₆ may have a substituent. Represents an arylene group.)

(In the formula, Ar represents an aryl group which may have a substituent, and X represents a halogen atom.) The amine compound according to claim 2, obtained by reacting the amine compound represented by the general formula (2) with two kinds of halogenated aryl compounds represented by the general formula (3). Mixture. X1 and X2 satisfy the following formulas (3) to (5) when the contents (mass%) of the amine compound satisfying the formula (1) and formula (2) are X1 and X2, respectively. The amine compound mixture according to any one of claims 1 to 3.
Formula (3) 30 ≦ X1 + X2 <100
Formula (4) 20 <= X1 <= 95
Formula (5) 5 <= X2 <= 45 An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer contains the amine compound mixture according to any one of claims 1 to 4. 6. The electrophotographic photosensitive member according to claim 5, wherein the photosensitive layer has a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. An exposure process for forming an electrostatic latent image on an electrophotographic photosensitive member using a semiconductor laser having an oscillation wavelength of 350 to 500 nm or a light source of a light emitting diode, and a developing process for visualizing the electrostatic latent image into a toner image An image forming method comprising: an electrophotographic photosensitive member according to claim 5 or 6. Exposure means for forming an electrostatic latent image on an electrophotographic photosensitive member using a semiconductor laser having an oscillation wavelength of 350 to 500 nm or a light source of a light emitting diode, and developing means for developing the electrostatic latent image into a toner image An image forming apparatus comprising: an electrophotographic photosensitive member according to claim 5 or 6.

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