JP5381068B2 - Organic photoreceptor, image forming method using the same, image forming apparatus and process cartridge - Google Patents

Description

  The present invention relates to an organic photoreceptor, an image forming method and an image forming apparatus using the same. More particularly, the present invention relates to an organic photoreceptor, an image forming method, and an image forming apparatus used for electrophotographic image formation used in the field of copying machines and printers.

  In recent years, in the fields of printing and color printing, the opportunities for using electrophotographic copying machines and printers are increasing. In the fields of printing and color printing, there is a strong tendency to demand high-quality digital monochrome images or color images. In response to such a demand, it has been proposed to form a high-definition digital image using a short wavelength laser beam as an exposure light source (see, for example, Patent Document 1).

  However, even if a short wavelength laser beam is used to narrow the exposure dot diameter and a fine electrostatic latent image is formed on the organic photoconductor, the image quality of the finally obtained electrophotographic image is sufficiently high. It cannot be said.

  This is because the photosensitive characteristics of the organic photoconductor and the charging characteristics of the toner of the developer do not have sufficient characteristics necessary for forming a fine dot latent image or a toner image.

  That is, as an electrophotographic photoreceptor, an organic photoreceptor developed for a conventional long wavelength laser (hereinafter, simply referred to as a photoreceptor) has poor sensitivity characteristics, and the exposure dot diameter is reduced using a short wavelength laser beam. When the narrowed image exposure is performed, the dot latent image is not clearly formed, and the reproducibility of the dot image tends to deteriorate.

  On the other hand, as the organic photoreceptor, a function-separated organic photoreceptor in which a charge generation layer and a charge transport layer are laminated is often used in order to satisfy photosensitive characteristics, mechanical characteristics, and the like.

  In this case, in the charge transport layer, the charge transport material developed for a conventional organic photoreceptor easily absorbs light having a short wavelength of 300 to 500 nm, and as a result, electrophotographic characteristics such as a decrease in sensitivity and an increase in residual potential. There was a problem of accelerating deterioration.

  As a charge transport material used in the charge transport layer of the photoreceptor for short wavelength laser exposure, for example, a charge transport material having a triphenylamine structure is known (see, for example, Patent Documents 2, 3 and 4). .

  However, a charge transport layer using these compounds having a triphenylamine structure as a charge transport material usually has a considerable film thickness of 15 to 45 μm, and therefore has a problem that the optical density is high and the sensitivity is not sufficient. In addition, there is a problem that durability is insufficient.

In order to compensate for this, it is desirable to use a highly sensitive gallium phthalocyanine pigment or titanyl phthalocyanine pigment as a charge generation material, but these pigments have a problem that transfer memory is likely to occur.
JP 2000-250239 A JP-A 63-278065 JP-A-7-261424 JP 2006-104183 A

  The present invention has been made to solve the above problems.

  That is, an object of the present invention is to provide an organic photoreceptor that can be used for a wide range of light sources having a light wavelength of 350 to 780 nm, can generate a stable image with high sensitivity, good charging characteristics, and no transfer memory. An image forming method using the same, an image forming apparatus, and a process cartridge are provided.

  As a result of intensive studies, the present inventors have found that the object of the present invention can be achieved by adopting the following configuration, and have reached the present invention.

1. In an organic photoreceptor in which a charge generation layer containing at least a phthalocyanine compound and a charge transport layer containing a charge transport material are provided on a conductive support, a compound represented by the following general formula ( 2) as the charge transport material An organic photoreceptor containing at least one of the above.

(In the general formula (2), R ₅ and R ₈ each represent an alkyl group or an alkoxy group having 1 to 5 carbon atoms. P is an integer of 0 to 5, q is an integer of 0 to 4, and r is 0. And an integer of ˜2, s represents an integer of 0 to 3. R ₉ and R ₁₀ each represents an alkyl group or an alkoxy group, and R ₉ and R ₁₀ may be bonded to form a ring structure. , F, G and H each represent a hydrogen atom, an optionally substituted alkyl group having 1 to 5 carbon atoms, an alkoxy group or an aryl group, provided that E, F, G and H are all hydrogen. It is not an atom.)
2. 2. The organophotoreceptor according to 1 above, wherein the phthalocyanine compound is at least one of a gallium phthalocyanine pigment and a titanyl phthalocyanine pigment.

  3. 3. An image forming method comprising: an exposure step of forming an electrostatic latent image using the organic photoreceptor according to 1 or 2; and a developing step of developing the electrostatic latent image into a toner image.

  4). 4. The image forming method according to 3 above, further comprising an exposure step of forming an electrostatic latent image using a light source of a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm.

  5. 3. An exposure means for forming an electrostatic latent image using a light source of a semiconductor laser or a light emitting diode using the organic photoreceptor described in 1 or 2 and having an oscillation wavelength of 350 to 500 nm, and the electrostatic latent image as a toner An image forming apparatus having a developing unit that visualizes an image, wherein the image forming apparatus is used in the image forming method described in the above item 3.

  6). 3. An exposure means for forming an electrostatic latent image using a light source of a semiconductor laser or a light emitting diode using the organic photoreceptor described in 1 or 2 and having an oscillation wavelength of 350 to 500 nm, and the electrostatic latent image as a toner A process cartridge used in an image forming apparatus having a developing unit that visualizes an image includes at least one of an organic photoreceptor, a charging unit, an image exposing unit, and a developing unit. A process cartridge configured to be able to be taken in and out.

  According to the present invention, an organic photoconductor capable of forming a stable image with high sensitivity, good charging characteristics, compatible with a wide range of light sources having a light wavelength of 350 to 780 nm, without generating a transfer memory, and the use thereof. The image forming method, the image forming apparatus, and the process cartridge can be provided.

  Hereinafter, the organic photoreceptor of the present invention will be described in detail.

  The charge generation layer of the present invention contains the phthalocyanine compound (pigment). However, gallium phthalocyanine pigments and titanyl phthalocyanine pigments, in particular, have high sensitivity characteristics, but tend to generate transfer memory. However, the problem of this highly sensitive phthalocyanine pigment can be solved by adopting the configuration of the present invention.

  The reason is that when a charge generation layer using a high-sensitivity titanyl phthalocyanine pigment and a charge transport layer containing a charge transport material of the general formula (1) or (2) are stacked, the interface between the charge generation layer and the charge transport layer It is considered that the charge transfer barrier becomes smaller and the charge accumulation of the transfer charge becomes smaller and the generation of the transfer memory can be suppressed.

  In particular, the present invention provides an organic electrophotographic photoreceptor having high sensitivity, excellent durability, and excellent image reproducibility and image reproducibility by including the specific compound as a charge transport material in the photosensitive layer. it can.

  In the present invention, the compound used as the charge transport material is a compound represented by the general formula (1) or (2).

[Compound represented by the general formula (1)]
In the general formula (1), R ₁ and R ₂ represent an alkyl group or an alkoxy group having 1 to 5 carbon atoms. R ₃ and R ₄ represent a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms or an alkoxy group. n represents an integer of 0 to 2, and o represents an integer of 0 to 3. l and m represent an integer of 0 to 5, and A, B, C, and D represent a hydrogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, or an aryl group. However, A, B, C and D are not simultaneously hydrogen atoms.

Examples of the alkyl group for R ₁ and R ₂ include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group. Examples of the alkoxy group in R _{1 to} R ₄ include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a pentoxy group.

Examples of the alkyl group for R ₃ and R ₄ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a cyclohexyl group. Examples of the alkoxy group in R _{1 to} R ₄ include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a pentoxy group. Examples of the substituted alkyl group for R ₃ and R ₄ include phenyl-substituted alkyl.

  Examples of the substituent for the alkyl group, alkoxy group or aryl group in A to D include an alkyl group and an alkoxy group.

  In addition, examples of the alkyl group in A to D include an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and a t-butyl group, an alkoxyalkyl group, and benzyl. And a substituted alkyl group such as a phenethyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. A phenyl group is mentioned as an aryl group.

  Specific examples of the compound represented by the general formula (1) are listed below.

  In order to synthesize the compound represented by the general formula (1), it is possible to synthesize diphenylamine and aryl halide by the Ullmann reaction using copper and alkali as a catalyst, or by the Suzuki coupling method using a palladium catalyst. Can do.

[Compound represented by formula (2)]
In this invention, it is a more preferable aspect when it is a compound represented by the said General formula (2) instead of the compound represented by General formula (1).

In the general formula _{(2), R 5, R} 6, R 7 and _{R 8} represent an alkyl group or an alkoxy group having 1 to 5 carbon atoms. p represents an integer of 0 to 5, q represents an integer of 0 to 4, r represents an integer of 0 to 2, and s represents an integer of 0 to 3. A, B, C and D have the same meanings as A, B, C and D in the general formula (1). However, E, F, G and H are not simultaneously hydrogen atoms.

Examples of the alkyl group and alkoxy group in R ₅ , R ₆ , R ₇ , and R ₈ include the same alkyl groups and alkoxy groups as those in R ₁ and R ₂ .

Examples of the alkyl group in R ₉ and R ₁₀ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and the ring structure formed by bonding R ₉ and R ₁₀ includes a cyclohexyl group, A cyclopentyl group etc. are mentioned. Moreover, a phenyl group is mentioned as an aryl group.

  Specific examples of the compound represented by the general formula (2) are listed below.

  The compound represented by the general formula (2) can be synthesized by reacting a triphenylamine having a biphenyl group with various ketone compounds using an acid catalyst. In addition, a diamino compound represented by the following general formula (3) and an aryl halide can be synthesized by various synthesis methods.

In General Formula (3), Ar ₁ represents a phenyl group which may have a substituent or a biphenyl group having a substituent in General Formula (1), and R ₁₁ and R ₁₂ are represented by the general formula ( It is synonymous with R ₉ and R _{10 in} 2).

  The reason why the photoreceptor using the compound according to the present invention as a charge transport material has high sensitivity and good durability is presumed as follows.

  In the compounds represented by the general formulas (1) and (2), having the above-mentioned biphenyl moiety has strong fluorescence, and energy is released by fluorescing the absorbed light, and the durability of the compound itself is high. improves. However, the biphenyl group described in Document 4 has a long absorption wavelength and absorbs semiconductor laser light having a vibration wavelength of 350 nm to 500 nm, so that the amount of light reaching the charge generation layer is reduced. The two phenyl groups in the biphenyl moiety have a substituent at each o-position when viewed from the bonding portion, whereby absorption at wavelengths of 350 nm to 500 nm is reduced. At the same time, when a layer containing other components used in the photoreceptor is formed, it is presumed that a film having good durability is formed by interaction with the other components.

[Configuration of photoconductor]
The constitution of the organic photoreceptor of the present invention will be described below.

  The organic photoconductor means an electrophotographic photoconductor constituted by having an organic compound having at least one of a charge generation function and a charge transport function, which are indispensable for the construction of an electrophotographic photoconductor. Photoconductors composed of organic charge generating materials or organic charge transport materials, and photoconductors composed of a polymer complex with charge generation and charge transport functions are organic photoconductors. Included in the photoreceptor.

The structure of the organic photoreceptor of the present invention contains a phthalocyanine pigment and at least a charge transport material represented by any one of the general formulas (1) and (2), and examples thereof include the following structures;
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 charge transport layer and a charge generation layer are sequentially laminated as a photosensitive layer on a conductive support;
4) A structure in which a surface protective layer is further formed on the photosensitive layer of the photoconductors 1) to 3).

  The photoconductor of the present invention may have any of the above structures, but the structure of 2) is most preferably used in the present invention.

  In addition, the organic photoreceptor of the present invention is one in which an undercoat layer (intermediate layer) is coated prior to the formation of the photosensitive layer on the conductive support, regardless of which of the above structures is provided. Good.

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

  The surface layer of the photoconductor is a layer in which the photoconductor is in contact with the air interface. When the laminated photosensitive layer and the surface protective layer are laminated on the conductive support, the surface protective layer is the outermost layer. is there.

  Next, the layer structure of the organophotoreceptor of the present invention will be described focusing on the structure of 2) above.

[Conductive support]
The conductive support used for the photosensitive member may be either a sheet or a cylinder, but a cylindrical conductive support is more preferable for designing an image forming apparatus compactly.

  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. A support is preferred. Exceeding the straightness and shake range 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. The conductive support according to the present invention is most preferably an aluminum support. 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.

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

  The intermediate layer 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. The number average primary particle size is preferably 5 nm to 100 nm, particularly from the viewpoint of uniformity of particle dispersion in the intermediate layer binder and prevention of dot image deterioration.

  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.

  The titanium oxide particles include anatase, rutile, brookite, and amorphous forms as crystal forms. Among these, the rutile-type titanium oxide pigment or the anatase-type titanium oxide pigment increases the rectification property of the charge passing through the intermediate layer, that is, increases the mobility of electrons, stabilizes the charging potential, and prevents the increase of the residual potential. In addition, the dot image can be prevented from being deteriorated, and is most preferable as the N-type semiconductive particle of the present invention.

  The N-type semiconductor particles are preferably surface-treated with a polymer containing an organosilicon compound such as a silane coupling agent or a methylhydrogensiloxane unit. 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 there is an effect on the reproducibility of good dot images.

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, and the like, but a random copolymer and a block copolymer are preferred. In addition to methylhydrogensiloxane, the copolymerization component may be one component or two or more components.

  The intermediate layer coating solution prepared for forming the intermediate layer is composed of a binder resin, a dispersion solvent and the like in addition to the N-type semiconductor 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 organic photoreceptor can be formed. Further, 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, the binder resin in which these particles are dispersed to form the layer structure of the intermediate layer is preferably a polyamide resin 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 organic 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 the polyamide, the following polyamide resin is also 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.

  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 prepared by a general polyamide synthesis method. An example of synthesis 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 from 0.3 to 10 μm, more preferably from 0.5 to 5 μm, from the standpoints of preventing black spots and preventing dot image deterioration due to an increase in residual potential.

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 or more. The volume resistance of the intermediate layer and the protective layer of the present invention prevents the occurrence of black spots due to a decrease in charge blocking property, decreases the image quality due to a decrease in potential holding property of the organic photoreceptor, and prevents the image quality from decreasing due to an increase in residual potential in repeated image formation. From the surface, 1 × 10 ⁸ to 10 ¹⁵ Ω · cm is preferable, 1 × 10 ⁹ to 10 ¹⁴ Ω · cm is more preferable, and 2 × 10 ⁹ to 1 × 10 ¹³ Ω · cm is more preferable. 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%
(Photosensitive layer)
The photosensitive layer structure of the photoreceptor of the present invention usually has an intermediate layer, and adopts a structure in which the function of the photosensitive layer is separated into a charge generation layer (CGL) and a charge transport layer (CTL).

  By adopting a configuration in which the functions are separated, it is possible to control the increase in residual potential with repeated use, and to easily control other electrophotographic characteristics according to the purpose. In the negatively charged photoconductor, it is preferable to employ a charge generation layer (CGL) on the intermediate layer and a charge transport layer (CTL) thereon.

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

(Charge generation layer)
In the photoreceptor of the present invention, a phthalocyanine compound is used as the charge generation material (CGM), and a titanyl phthalocyanine pigment or a gallium phthalocyanine pigment having high sensitivity to short-wave to long-wavelength LEDs and laser light is preferable. For example, A-type titanyl phthalocyanine (JP-A-62-97064) having a maximum peak at 26.3 degrees in the X-ray diffraction spectrum (± 0.2 degrees tolerance), characterized by 7.6, 28.6 degrees B-type titanyl phthalocyanine having a typical peak (Japanese Patent Laid-Open No. 61-239248), Y-type titanyl phthalocyanine having a maximum peak at 27.3 degrees (Japanese Patent Laid-Open No. 3-35245) and 2 having stereoregularity , Titanyl phthalocyanine known as a titanyl phthalocyanine adduct of 3-butanediol (Japanese Patent Laid-Open No. 8-822942) and the like can be used. Alternatively, there are gallium phthalocyanines such as hydroxygallium phthalocyanine (Japanese Patent Laid-Open No. 5-263007) and chlorogallium phthalocyanine. Among these, Y-type titanyl phthalocyanine (y-TiOPc) is preferable.

  The titanyl phthalocyanine pigment preferably used in the present invention is preferably a titanyl phthalocyanine pigment having a maximum diffraction peak at a Bragg angle (2θ ± 0.2 °) of 27.3 ° in an X-ray diffraction spectrum by Cu-Kα characteristic X-ray. Furthermore, in addition to the maximum diffraction peak of 27.3 °, the titanyl phthalocyanine pigment has clear peaks at Bragg angles (2θ ± 0.2 °) of 24.1 °, 14.3 °, and 9.6 °. Is more preferable. Also preferred is a titanyl phthalocyanine pigment having a remarkable diffraction peak at a Bragg angle (2θ ± 0.2 °) of 7.5 ° and 28.7 ° in an X-ray diffraction spectrum by Cu-Kα characteristic X-ray. Titanyl phthalocyanine having prominent diffraction peaks at .5 °, 22.6 °, 24.5 °, 25.4 °, 28.7 ° and a maximum diffraction peak at 7.5 ° or 28.7 ° A pigment is more preferable.

  The charge generation layer preferably uses a binder as a dispersion medium for CGM. As the binder, known resins can be used, and the most preferred resins include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, phenoxy resin and the like.

  The ratio of the binder to the charge generating material is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder. 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 μm to 1.5 μm.

(Charge transport layer)
In the present invention, the charge transport layer may be a single layer or a plurality of charge transport layers. When composed of a plurality of charge transport layers, the uppermost charge transport layer preferably contains inorganic fine particles.

  The charge transport layer contains a charge transport material (CTM) and a binder resin that disperses and forms a CTM. Other substances may contain additives such as inorganic fine particles and antioxidants as necessary.

  The charge transport material (CTM) contains at least one or more of the compounds represented by the above general formulas (1) and (2). In addition to this, known hole transport properties (P type) The charge transport material (CTM) may be used in combination. For example, triphenylamine derivatives, hydrazone compounds, styryl compounds, benzidine compounds and the like other than the compounds according to the present invention can be used. These charge transport materials are usually dissolved in a suitable binder resin to form a layer. However, the charge transport material used in combination is preferably used in a mass part of less than ½ of the total mass part of the compounds represented by the general formula (1) and the general formula (2) according to the present invention.

  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, high molecular 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 from the viewpoint of preventing the deterioration of dot reproducibility. Moreover, it is preferable that the film thickness of the electric charge transport layer used as a surface layer is 1.0-8.0 micrometers.

  Solvents or dispersion media used to form layers such as intermediate layers, charge generation layers, and charge transport layers 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 cello Lube, 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 may be used alone or as a mixed solvent of two or more.

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

  Among the coating liquid supply type coating apparatuses, the coating processing method using the 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 compared to the dip coating method, so that the lower layer component hardly elutes to the upper layer side, and the coating tank Can be applied without degrading the dispersibility of the inorganic fine particles of the present invention.

  The surface layer of the photoreceptor of the present invention preferably contains an antioxidant from the viewpoint of preventing image blur. 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.

  Antioxidants typically represent the prevention or suppression of the action of oxygen on auto-oxidizing substances present in or on the surface of an organic photoreceptor under light, heat, discharge, or other conditions. It is a substance with the property to do. 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.

[Image Forming Method and Image Forming Apparatus]
Next, an image forming apparatus using the photoreceptor according to 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 comprising the illumination lamp and the first mirror constituting the scanning optical system, and the V-shaped first image is located. Reading is performed by moving the second mirror unit 16 composed of 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 serving as a transferring means (transfer process), cleaning device (cleaning process) 26 for the photosensitive member 21, and light discharging means (light discharging process). PCL (precharge lamps) 27 are 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 photoconductor 21 uses the organic photoconductor of the present invention and is driven to rotate 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.

  The image forming apparatus of the present invention includes an exposure unit that uses a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm as an image exposure light source when an electrostatic latent image is formed on a photoreceptor. Using these image exposure light sources, the exposure dot diameter in the writing direction is narrowed down to 10 to 50 μm, and digital exposure is performed on the organic photoreceptor, so that it is 600 dpi (dpi: the number of dots per 2.54 cm) or more. A high resolution electrophotographic image of 2500 dpi can be obtained.

The exposure dot diameter refers to the length of the exposure beam along the main scanning direction (Ld: measured at the maximum length) 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 such a scanning optical system and LED solid scanner using a semiconductor laser, there is a Gaussian distribution and Lorentz distribution and the like 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 image forming apparatus of the present invention has a developing unit that visualizes the electrostatic latent image into a toner image. 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 organic photoreceptor according to 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. Further, a manual paper feeding unit 42 for manually feeding paper is provided on the side, 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 fed again. The transport path 40, the pre-transfer roller 43a, and the paper feed path 46 The transfer paper P is guided while being guided by the entry guide plate 47 and is placed and conveyed on the transfer conveyance belt 454 of the transfer conveyance belt device 45 by the transfer electrode 24 and the separation electrode 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 switched back by the transfer paper reversing unit 179, and the rear end portion of the transfer paper P becomes the leading end portion and transported into the duplex copying paper supply unit 130. 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. Further, at least one of a charging device, 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 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. The paper transport unit 21 and the fixing unit 24 are included. 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 a cleaning unit 6b. Consists of.

  Next, FIG. 3 shows a color image forming apparatus using the organic photoreceptor of the present invention (a copying machine having at least a charging means, an exposing means, a plurality of developing means, a transfer means, a cleaning means and an intermediate transfer body around the organic photoreceptor. 1 is a cross-sectional view of a 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 first color yellow toner image 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 photoreceptor 1 after the transfer of the first color yellow toner image corresponding to the intermediate transfer body 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 photoreceptor 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. is there.

  When the superimposed color toner image transferred onto the belt-shaped intermediate transfer member 70 is transferred to 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 paper 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 heated and fixed.

  The image forming apparatus of the present invention is generally applicable to electrophotographic apparatuses such as an electrophotographic copying machine, a laser printer, an LED printer, and a liquid crystal shutter type printer, and further displays, recordings, light printing, plate making, and facsimiles using electrophotographic technology. The present invention can be widely applied to such devices.

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

Production of Photoreceptor 1 Photoreceptor 1 was produced as follows.

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

(Preparation of intermediate layer coating solution)
The following intermediate layer dispersion is diluted twice with the same mixed solvent, and is allowed to stand overnight and then filtered (filter; rigesh mesh filter made by Nippon Pole Co., Ltd., nominal filtration accuracy: 5 microns, pressure: 50 kPa). 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 hydrophobization degree of 33) 6 parts ethanol / n-propyl alcohol / THF (= 45/20/30 mass ratio) 10 parts The above components are mixed and dispersed in a batch system for 10 hours using a sand mill disperser. Prepared.

Charge generation layer: CGL
Charge generating material (CGM): Exemplified compound CGM-1 24 parts Polyvinyl butyral resin “ESREC BL-1” (manufactured by Sekisui Chemical Co., Ltd.) 12 parts 2-butanone / cyclohexanone = 4/1 (v / v) 300 parts Were mixed and dispersed using a sand mill to prepare a charge generation layer coating solution. This coating solution was applied by a dip coating method to form a charge generation layer having a dry film thickness of 0.5 μm on the intermediate layer.

Charge transport layer (CTL)
Charge transport material (Exemplary Compound CTM1) 225 parts Polycarbonate (Z300: manufactured by Mitsubishi Gas Chemical Company) 300 parts Antioxidant (Exemplary Compound AO1-3) 3 parts Dichloromethane 2000 parts Silicon oil (KF-96: manufactured by Shin-Etsu Chemical Co., Ltd.) 1 Parts were mixed and dissolved to prepare a charge transport layer coating solution 1. This coating solution was applied onto the charge generation layer by a dip coating method and dried at 120 ° C. for 70 minutes to form a charge transport layer having a dry film thickness of 20.0 μm.

Production of photoconductors 2 to 17 Photoconductors 2 to 17 were produced in the same manner as photoconductor 1 except that the charge generation material and the charge transport material were changed as shown in Table 1 in the production of photoconductor 1.

  In the following “Table 1”, CTM-R1, CTM-R2, and CGM-R1 represent the following compounds.

  However, A-TiOPc represents A-type titanyl phthalocyanine, B-TiOPc represents B-type titanyl phthalocyanine, y-TiOPc represents Y-type titanyl phthalocyanine, and Ga-Pc represents gallium phthalocyanine.

<< Evaluation of photoconductor >>
The prepared photoreceptor was evaluated for sensitivity, repeatability, potential stability and image evaluation (1 dot line, 2 dot line) as follows.

(sensitivity)
Basically, a full-color compound machine bizhub PRO C6500 (manufactured by Konica Minolta Business Technologies, Inc.) having the configuration shown in FIG. 1 (using a 405 nm semiconductor laser as an image exposure light source, beam diameter of 30 μm, 1200 dpi [dpi: per 2.54 cm] The number of dots in the exposure] was modified to process conditions for exposure, and further modified so that the surface potential of the photoreceptor can be measured with a surface potential meter. The surface was charged and exposed to light, and the amount of light necessary for the surface potential to decay to -350 V was measured to determine the sensitivity (E _1/2 ).

  Similarly, the sensitivity was similarly measured by changing the exposure light source to a semiconductor laser of 500 nm or 780 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. Repeated times, Vd and Vl fluctuation amounts (ΔVd, ΔVl) were measured, and the repeated characteristics of charging and exposure were taken as one of durability indicators. Note that minus represents a decrease in potential, and plus represents an increase in potential.

(Potential stability)
The effect of external light irradiation was measured. Using the modified machine, the exposed portion potential (Vi) before and after irradiating the photosensitive member with a 1000 lux fluorescent lamp for 30 minutes was measured to evaluate the potential stability, and was used as one of the durability indicators.

(Dot image evaluation)
Using a modified machine (use of a 405 nm semiconductor laser) used for sensitivity measurement, the photoconductors 1 to 16 were mounted on the copying machine, and dot images were evaluated and used as an index of image reproducibility. In addition, dot images were also evaluated on the photoreceptor after irradiation with a fluorescent lamp, and image reproducibility due to deterioration was evaluated. Evaluation items and evaluation criteria are shown below. In addition, dpi represents the number of dots per 2.54 cm.

<1 dot line>
A one-dot line and a solid black image were produced 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 white line of 2 dot lines was produced 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”.

(Transfer memory)
By changing the transfer condition of the full color multifunction machine bizhub PRO C6500 to a transfer current of 20 μA, 30 μA, and 40 μA, 10 images with a mixture of solid black and solid white are continuously printed, and then a uniform halftone image is printed. It was determined whether the solid black and solid white history appeared in the halftone image (memory generation) or not (no memory generation).

◎: No memory generated ○: Memory generated, but within practical range (with practicality)
×: Memory generation is remarkable and out of practical range (no practicality)
The results of the above evaluation are shown in Table 2.

The photoreceptors 2, 6 to 8 and 10 in the present invention , and the photoreceptors 1, 3 to 5 and 9 in the reference examples are all at or above the level where they have practical properties, but the photoreceptor 11 outside the present invention. It can be seen that ˜13 is a level at which any of the characteristics is problematic.

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 an organic photoreceptor 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 (6)

In an organic photoreceptor in which a charge generation layer containing at least a phthalocyanine compound and a charge transport layer containing a charge transport material are provided on a conductive support, a compound represented by the following general formula ( 2) as the charge transport material An organic photoreceptor containing at least one of the above.

(In the general formula (2), R ₅ and R ₈ each represent an alkyl group or an alkoxy group having 1 to 5 carbon atoms. P is an integer of 0 to 5, q is an integer of 0 to 4, and r is 0. And an integer of ˜2, s represents an integer of 0 to 3. R ₉ and R ₁₀ each represents an alkyl group or an alkoxy group, and R ₉ and R ₁₀ may be bonded to form a ring structure. , F, G and H each represent a hydrogen atom, an optionally substituted alkyl group having 1 to 5 carbon atoms, an alkoxy group or an aryl group, provided that E, F, G and H are all hydrogen. It is not an atom.) 2. The organophotoreceptor according to claim 1, wherein the phthalocyanine compound is at least one of a gallium phthalocyanine pigment and a titanyl phthalocyanine pigment. 3. An image forming method comprising: an exposure step for forming an electrostatic latent image using the organic photoreceptor according to claim 1; and a development step for developing the electrostatic latent image into a toner image. 4. The image forming method according to claim 3, further comprising an exposure step of forming an electrostatic latent image using a light source of a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm. An exposure means for forming an electrostatic latent image using a light source of a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm, wherein the organic photoreceptor according to claim 1 or 2 is used, and the electrostatic latent image An image forming apparatus having a developing unit that visualizes a toner image, wherein the image forming apparatus is used in the image forming method according to claim 3. An exposure means for forming an electrostatic latent image using a light source of a semiconductor laser or a light emitting diode having an oscillation wavelength of 350 to 500 nm, wherein the organic photoreceptor according to claim 1 or 2 is used, and the electrostatic latent image A process cartridge used in an image forming apparatus having a developing unit that visualizes a toner image includes at least one of an organic photoreceptor, a charging unit, an image exposing unit, and a developing unit, and the image forming apparatus. A process cartridge that is configured to be able to be inserted into and removed from the cartridge.

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