JP2012022140A - Electrophotographic photoreceptor, electrophotographic method using the same, electrophotographic apparatus and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which has high durability against repeated usage for long term and with which the image density decrease or image deterioration due to image blur is suppressed and not only the variation in course of day of an exposure part potential but also the variation in job is suppressed and images of high quality can be stably obtained.SOLUTION: In an electrophotographic photoreceptor having a photosensitive layer on an electric conductive supporter, the photosensitive layer includes an electric charge transport material expressed by the following formula (1) and alkylamine compound with a special structure. (In the formula, Rand Rmean substituted or unsubstituted alkyl groups or substituted or unsubstituted aryl groups and at least one of the Rand Ris substituted or unsubstituted aryl groups.)

Description

  The present invention relates to an electrophotographic photoreceptor, and more specifically, an electrophotographic photoreceptor containing a specific charge transport material and a specific amine compound, and an electrophotographic method, an electrophotographic apparatus, and an electrophotography using the electrophotographic photoreceptor. The present invention relates to a process cartridge.

  An electrophotographic photoreceptor (hereinafter also referred to as “photoreceptor”) has a function of holding a surface charge in a dark place, a function of receiving light to generate a charge, and a function of receiving light and receiving a charge. It is necessary to have a function of transporting, so-called single-layer type photoreceptors that have these functions in one layer, a layer that mainly contributes to charge generation, surface charge in the dark, and charge transport during photoreception. There is a so-called function-separated stacked type photoreceptor in which a function-separated layer and a contributing layer are stacked.

  For example, a Carlson method is applied to image formation by electrophotography using these photoreceptors. Image formation by this method is performed by charging a photoconductor in a dark place by corona discharge, forming an electrostatic latent image such as text or a picture of an original on the surface of the charged photoconductor, The image is developed with toner, and the developed toner image is fixed on a support such as paper. After the toner image is transferred, the photoreceptor is subjected to charge removal, residual toner removal, light charge removal, etc., and then reused. Provided.

  In recent years, electrophotographic photoreceptors using organic substances have been put into practical use due to advantages such as flexibility, thermal stability, and film formability. Recently, a function-separated laminated type photoconductor comprising a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material as the photosensitive layer has become the mainstream, and in particular, an organic pigment is deposited as a charge generation material Many negatively charged photoreceptors have been proposed in which a layer or a layer dispersed in a resin is used as a charge generation layer, and an organic low molecular weight compound is used as a charge transport material and a layer dispersed in a resin is used as a charge transport layer.

  Organic materials have many advantages that inorganic materials do not have, but at the same time, those that sufficiently satisfy all the characteristics required for electrophotographic photoreceptors have not been obtained. That is, the image quality is deteriorated due to a decrease in charging potential, an increase in residual potential, a change in sensitivity, and the like due to repeated use. Although not all of the causes of this deterioration have been elucidated, as one of the factors, oxidizing gases such as ozone and NOx released from corona discharge chargers, and oxidizing gases such as ozone and NOx in the atmosphere Has been found to cause significant damage to the photosensitive layer. In other words, these oxidizing gases cause various changes in properties by causing a chemical change with the material in the photoreceptor or by forming an adsorbate on the surface of the photosensitive layer. Causes increase in potential and decrease in resolution (image blur) due to decrease in surface resistance. As a result, the image quality is remarkably deteriorated and the life of the photoreceptor is shortened.

  As a countermeasure against these problems, proposals have been made to prevent deterioration by adding an antioxidant or a stabilizer to the photosensitive layer. For example, the addition of a hindered phenol-based antioxidant and a hindered amine-based antioxidant to the photosensitive layer (for example, see Patent Document 1) and the addition of an amine compound (for example, see Patent Documents 2 to 6) have been proposed. And these proposals had a certain effect.

By the way, in recent years, methods such as applying a lubricant to the surface of the photoconductor and providing a surface protective layer have been adopted to provide high wear resistance, and photoconductor wear can be suppressed by process design around the photoconductor. As a result, the photoreceptor can be used for a long period of time. For this reason, it has become very important to improve the electrostatic characteristics of the photoconductor, but in order to maintain high image quality over a long period of time, the addition of conventional antioxidants and the like has become insufficient. .
Recently, full-color and high-speed electrophotographic apparatuses are rapidly progressing, and accordingly, demand is diversified from a general office area to a SOHO area or a light printing area. In particular, in the light printing field, the printing volume is remarkably increased and the demand for image quality stability is increased. Therefore, it is indispensable to further increase the durability and stability of the organic photoreceptor.

  The problem of the exposure portion potential fluctuation in the electrophotographic apparatus used in the light printing field is that one job (one operation) starts printing rather than the exposure portion potential fluctuation when printing is performed for a relatively long time. The exposure portion potential fluctuation when the process is finished and the next printing is resumed is larger as a problem. Hereinafter, the former is referred to as daily fluctuation of the exposure part potential, and the latter is referred to as intra-job fluctuation of the exposure part potential. In the case of daily fluctuations in the exposure part potential, the effect is not noticeable, and the potential can be corrected in the electrophotographic apparatus, so the problem is not so great. In addition, if the potential fluctuates by several tens or several sheets in the job, it becomes difficult to correct the potential, which is a serious problem.

In particular, in the light printing field, there is a demand for printing a large amount of the same image pattern with one job. In this case, if the fluctuation in the exposure portion potential in the job is large, the image density changes and the image quality consistency is lowered. become. If it is a character-based image pattern, it will not stand out so much, but if it is an image-based and full-color image pattern, not only the image density but also the color will change, leading to a very serious problem. That is, it is required to reduce the exposed portion potential of the photosensitive member and further suppress the exposed portion potential fluctuation in long-term repetitive printing, not only the daily fluctuation, but also the fluctuation in the job.
In fact, the electrophotographic photoreceptors described in Patent Documents 1 to 6 do not always meet such requirements.

  The object of the present invention has high durability even for repeated use over a long period of time, and suppresses image deterioration due to image density reduction or image blurring. An object of the present invention is to provide an electrophotographic photosensitive member that suppresses fluctuations in the job and can stably obtain high-quality images. Another object of the present invention is to provide a highly durable and highly stable electrophotographic method, electrophotographic apparatus, and electrophotographic apparatus, in which image density is always stable and image quality is consistent by using the electrophotographic photosensitive member. A process cartridge is provided.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by the inventions described in the following (1) to (9), and have reached the present invention.

(1) In an electrophotographic photosensitive member having at least a photosensitive layer on a conductive support, the photosensitive layer is represented by the following general formula (1) and an amine represented by the following general formula (2) An electrophotographic photoreceptor comprising a compound.

(In the formula, R ₁ and R ₂ represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, and at least one of R ₁ and R ₂ is a substituted or unsubstituted aryl group.)

(In the formula, A and B are selected from the following (i) and (ii), respectively, and may be the same or different.
(I) _-CH 2 X
_(Ii) -CH 2 _CH 2 Y
However, X and Y each represent an aromatic residue, and these may have a substituent. )

(2) A charging step for charging the surface of the electrophotographic photosensitive member, an image exposure step for forming an electrostatic latent image on the electrophotographic photosensitive member, and a development for developing the electrostatic latent image to form a toner image. An electrophotographic method in which a process and a transfer process in which the toner image is directly transferred to a recording material or transferred to a recording material via an intermediate transfer member, wherein the electrophotographic photosensitive member is described in (1) above. An electrophotographic method comprising using the electrophotographic photosensitive member described above.

(3) The electrophotographic method is a digital method, and the image exposure step forms an electrostatic latent image on the electrophotographic photosensitive member by light irradiation using a semiconductor laser (LD) or a light emitting diode (LED) as a light source. The electrophotographic method as described in (2) above, wherein

(4) an electrophotographic photosensitive member, a charging means for charging the surface of the electrophotographic photosensitive member, an image exposing means for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member, and developing the electrostatic latent image. An electrophotographic apparatus comprising: a developing unit that forms a toner image; and a transfer unit that directly transfers the toner image to a recording material or transfers the toner image to an intermediate transfer member. And an electrophotographic photosensitive member according to (1).

(5) The electrophotographic apparatus is a digital system, and the image exposure means uses a semiconductor laser (LD) or a light emitting diode (LED) that forms an electrostatic latent image on the surface of the electrophotographic photosensitive member as a light source. The electrophotographic apparatus according to (4), wherein the electrophotographic apparatus is provided.

(6) The tandem structure having a plurality of image forming elements each including at least the electrophotographic photosensitive member, the charging unit, the developing unit, and the transfer unit (4) or (5) ).

(7) A transfer unit that primarily transfers the toner image on the electrophotographic photosensitive member to an intermediate transfer member, and a transfer unit that secondarily transfers the toner image formed on the intermediate transfer member onto the recording material. The electrophotographic apparatus according to any one of (4) to (6) above, wherein

(8) The image that is secondarily transferred onto the recording material is a color image composed of a plurality of colors of toner, and the intermediate toner is sequentially superimposed on the intermediate transfer member by the primary transfer unit. The image according to (7), wherein an image is formed on a transfer body, and the image on the intermediate transfer body is secondarily transferred onto the recording material at once by the secondary transfer unit. apparatus.

  The electrophotographic photosensitive member according to the above (1), charging means for charging the surface of the electrophotographic photosensitive member, image exposure means for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member, and the electrostatic latent image At least one selected from developing means for developing to form a toner image, cleaning means for cleaning the surface of the electrophotographic photosensitive member, and transfer means for transferring the toner image directly to a recording material or transferring it to an intermediate transfer member. And a process cartridge for an electrophotographic apparatus.

According to the electrophotographic photosensitive member of the present invention, the charge transport material contains the charge transport material represented by the general formula (1) and the amine compound represented by the general formula (2) in the photosensitive layer. The deterioration of the charge transport material is suppressed without deteriorating the function, and the characteristics of the photoreceptor are stabilized even after repeated use over a long period of time (for example, the electrostatic characteristics are stabilized and the exposure portion potential and the residual potential are increased). Furthermore, fluctuations in the job are also suppressed, and a high-quality image can be obtained stably over a long period of time.
In addition, according to the present invention, an electrophotographic method, an electrophotographic apparatus, and an electrophotographic apparatus that can output an image with little change in image density and color, that is, excellent image quality consistency, by using the electrophotographic photosensitive member. An apparatus process cartridge is provided.

It is a schematic sectional drawing which shows the example of 1 structure of the electrophotographic photoreceptor in this invention. It is a schematic sectional drawing which shows another structural example of the electrophotographic photoreceptor in this invention. It is a schematic sectional drawing which shows another example of a structure of the electrophotographic photoreceptor in this invention. It is a schematic sectional drawing which shows another example of a structure of the electrophotographic photoreceptor in this invention. It is the schematic for demonstrating the electrophotographic process and electrophotographic apparatus of this invention. It is the schematic which shows another example of the electrophotographic formation process and electrophotographic apparatus in this invention. 1 is a schematic configuration diagram illustrating an example of a printer according to an embodiment of the present invention. 1 is a schematic diagram illustrating an example of a tandem type image forming apparatus according to the present invention. It is a schematic diagram which shows the structural example of the process cartridge in this invention. It is a powder spectrum of titanyl phthalocyanine used in Examples 11-13.

Hereinafter, the present invention will be described in detail.
First, description will be given based on the drawings from the electrophotographic photosensitive member of the present invention.
[Electrophotographic photoconductor]
FIG. 1 is a sectional view showing the structure of the electrophotographic photosensitive member of the present invention. A photosensitive layer 33 mainly composed of a charge generating material and a charge transporting material is provided on a conductive support 31.
FIG. 2 is a cross-sectional view showing another configuration example of the electrophotographic photosensitive member of the present invention. On the conductive support 31, a charge generation layer 35 mainly composed of a charge generation material and a charge transport material are mainly used. The charge transport layer 37 as a component has a laminated structure.
FIG. 3 is a cross-sectional view showing still another configuration of the electrophotographic photosensitive member of the present invention. A photosensitive layer 33 mainly composed of a charge generating material and a charge transporting material is provided on a conductive support 31. Further, a protective layer 39 is provided on the surface of the photosensitive layer 33. In this case, the protective layer 39 may contain an amine compound represented by the general formula (2).
FIG. 4 is a cross-sectional view showing still another configuration of the electrophotographic photosensitive member of the present invention, in which a charge generation layer 35 mainly composed of a charge generation material and a charge transport material are mainly formed on a conductive support 31. The charge transport layer 37 as a component is laminated, and a protective layer 39 is further provided on the charge transport layer. In this case, the protective layer 39 may contain an amine compound represented by the general formula (2).

[Conductive support]
Examples of the conductive support 31 include those having a volume resistance of 10 ¹⁰ Ω · cm or less, for example, metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, indium oxide, etc. These are metal oxides coated with film or cylindrical plastic, paper, etc. by vapor deposition or sputtering, or plates such as aluminum, aluminum alloy, nickel, stainless steel, etc., and such methods as extrusion and drawing. After forming the tube, it is possible to use a tube that has been surface-treated by cutting, superfinishing, polishing, or the like. Further, an endless nickel belt or an endless stainless steel belt disclosed in Japanese Patent Application Laid-Open No. 52-36016 can also be used as the conductive support 31.

In addition, a material obtained by dispersing conductive powder in an appropriate binder resin and coating it on the support can also be used as the conductive support 31 of the present invention. Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, or metal oxide powder such as conductive tin oxide and ITO. It is done. The binder resin used at the same time is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin.
Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.

  Furthermore, it is electrically conductive by a heat-shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark) on a suitable cylindrical substrate. Those provided with a conductive layer can also be used favorably as the conductive support 31 of the present invention.

[Photosensitive layer]
Next, the photosensitive layer will be described. The photosensitive layer may be a single layer photosensitive layer (FIGS. 1 and 3) including a charge generation material and a charge transport material, or may be a laminated type (FIGS. 2 and 4) including a charge generation layer and a charge transport layer. However, for convenience of explanation, the photosensitive layer having a laminated structure will be described first.

<Charge generation layer>
The charge generation layer 35 is a layer mainly composed of a charge generation material. A known charge generation material can be used for the charge generation layer 35, and representative examples thereof include monoazo pigments, disazo pigments, trisazo pigments, perylene pigments, perinone pigments, quinacridone pigments, and quinone condensed polycycles. Examples thereof include compounds, squaric acid dyes, other phthalocyanine pigments, naphthalocyanine pigments, and azulenium salt dyes. These charge generation materials may be used alone or in combination of two or more.

In the charge generation layer 35, a charge generation material is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, an attritor, a sand mill, an ultrasonic wave, or the like. It is formed by coating on top and drying.
The binder resin used as necessary includes polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly-N-vinylcarbazole, poly Examples include acrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulosic resin, casein, polyvinyl alcohol, and polyvinyl pyrrolidone. The amount of the binder resin is suitably 0 to 500 parts by weight, preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generating material. The binder resin may be added before or after dispersion.

  Examples of the solvent include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin, etc. , Ester solvents and ether solvents are preferably used. These may be used alone or in combination of two or more.

The charge generation layer 35 includes a charge generation material and a binder resin as main components, but may contain various additives such as a sensitizer, a dispersant, a surfactant, and silicone oil.
As a coating method of the coating solution (charge generation layer forming solution), methods such as dip coating, spray coating, beat coating, nozzle coating, spinner coating, and ring coating can be used.
The thickness of the charge generation layer 35 is suitably about 0.01 to 5 μm, preferably 0.1 to 2 μm.

<Charge transport layer>
The charge transport layer 37 is a layer mainly composed of a charge transport material, and in the present invention, the charge transport layer 37 contains a charge transport material represented by the general formula (1) and an amine compound represented by the general formula (2). To do.

(In the formula, R ₁ and R ₂ represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, and at least one of R ₁ and R ₂ is a substituted or unsubstituted aryl group.)

Here, the alkyl group has 1 to 6 carbon atoms, and the substituent of the alkyl group includes a fluoro group, a cyano group, a phenyl group, halogen, or a linear or branched chain having 1 to 6 carbon atoms. And a phenyl group substituted with a cyclic alkyl group.
On the other hand, the aryl group is a phenyl group, a naphthyl group, or a benzyl group. Substituents for the aryl group include alkyl groups having 1 to 6 carbon atoms, alkyloxy groups having 1 to 6 carbon atoms, phenyl groups, and alkyl groups. (C1-C6) substituted phenyl group etc. are mentioned.

  Preferred examples of the charge transport material represented by the general formula (1) are given below. However, the present invention is not limited to these compounds.

However, in the formula, A and B are each selected from the following i) ii) and may be the same or different.
i) _-CH 2 X
_ii) -CH 2 _CH 2 Y
However, X and Y each represent an aromatic residue, and these may have a substituent.

  Here, examples of the aromatic ring of the aromatic residue include a benzene ring, a naphthalene ring, and an anthracene ring. In addition, examples of the substituent that the aromatic residue may have include a methyl group, an ethyl group, and an n-propyl group.

  Preferred examples of the amine compound represented by the general formula (2) are given below. However, the present invention is not limited to these compounds.

In the present invention, by combining the charge transporting material represented by the general formula (1) and the amine compound represented by the general formula (2), the electrostatic characteristics are stabilized even in long-term repeated use. Variations can also be reduced.
By combining the charge transporting substance represented by the general formula (1) and the amine compound represented by the general formula (2), the electrostatic characteristics are stabilized even in repeated use over a long period of time, and the fluctuation in the job is also reduced. The reason for this has not been clarified in detail, but one reason is that the amine compound represented by the general formula (2) has excellent gas resistance. This is presumably because the amine compound represented by the general formula (2) has a strong basic amino group, which can prevent the charge transport material from being altered by the oxidizing gas. In addition, unlike antioxidants, they do not have polar groups that easily trap charges, and they themselves have charge transport properties, so even if they are added in relatively large amounts, they have the effect of increasing the exposed area potential and residual potential. Is estimated to be reduced.
Furthermore, it is presumed that the amine compound represented by the general formula (2) has a specific influence on the charge transport function with respect to the charge transport material represented by the general formula (1). Due to the excellent gas resistance of the amine compound, it suppresses the deterioration of the charge transport material due to the oxidizing gas such as ozone and NOx generated by the corona charger in the apparatus, and further has less influence on the charge transport function. The electrostatic characteristics can be stabilized even after repeated use, and fluctuations within the job can be reduced.

  The content of the charge transport material represented by the general formula (1) in the charge transport layer 37 is preferably 30 to 200 parts by weight with respect to 100 parts by weight of the binder resin. When the content of the charge transport material represented by the general formula (1) is less than 30 parts by weight with respect to 100 parts by weight of the binder resin, the electrical characteristics deteriorate, for example, the residual potential increases. On the other hand, when the amount is more than 200 parts by weight with respect to 100 parts by weight of the binder resin, mechanical properties such as wear resistance deteriorate.

  Furthermore, the charge transport material represented by the general formula (1) and other charge transport materials can be mixed and used. In this case, the content ratio of the charge transport material represented by the general formula (1) and the other charge transport material is (charge transport material represented by the general formula (1)): (other charge transport material) = The range of 50:50 to 95: 5 is preferable, and the range of 70:30 to 95: 5 is more preferable.

Examples of the other charge transport materials include the following.
Charge transport materials include electron transport materials and hole transport materials.
Examples of the electron transporting material include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and benzoquinone derivatives.

Examples of hole transport materials include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., bisstilbene derivatives, enamine derivatives, etc. Known materials may be mentioned.
These charge transport materials may be used alone or in combination of two or more.

  The content of the amine compound represented by the general formula (2) in the charge transport layer 37 is 1 to 30 parts by weight of the amine compound with respect to 100 parts by weight of the charge transport material represented by the general formula (1). It is preferable that When the content of this compound is less than 1 part by weight, the decrease in charging and the image blur due to the effects of ozone and NOx are remarkable. .

  As the binder resin constituting the charge transport layer, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer Copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin And thermoplastic or thermosetting resins such as melamine resin, urethane resin, phenol resin, and alkyd resin.

  The film thickness of the charge transport layer is preferably 50 μm or less, and preferably 25 μm or less from the viewpoint of resolution and responsiveness. The lower limit varies depending on the system to be used (particularly charging potential), but is preferably 5 μm or more.

  As the solvent of the coating solution used for forming the charge transport layer, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone or the like is used. These may be used alone or in combination of two or more. As a coating method of the coating solution, a conventional coating method such as dip coating, spray coating, beat coating, nozzle coating, spinner coating, ring coating, or the like can be used.

<Single layer type photosensitive layer>
Next, the case where the photosensitive layer has a single layer structure (in the case of FIGS. 1 and 3) will be described.
The photosensitive layer 33 can be formed by dissolving or dispersing a charge generation material, a charge transport material and a binder resin in a suitable solvent, and applying and drying the solution. The photosensitive layer 33 contains a charge transport material represented by the general formula (1) and an amine compound represented by the general formula (2). Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.

  Also in the single-layer type photosensitive layer 33, the materials (charge generating material, charge transporting material, binder resin) used for the above-mentioned laminated photosensitive layer (charge generating layer, charge transporting layer) can be used in the same manner. . In the case of the photosensitive layer 33 having a single layer structure, it is preferable to use the above-described electron transporting material in combination as a charge transporting material for high sensitivity.

In the photosensitive layer 33 having a single layer structure, the charge generation material is 0.1 to 30% by weight, preferably 0.5 to 5% by weight, based on the entire photosensitive layer. When the concentration of the charge generating substance is low, the photoreceptor sensitivity tends to decrease, and when the concentration is high, the chargeability and the film strength tend to decrease.
The content of the charge transport material represented by the general formula (1) is preferably 30 to 200 parts by weight with respect to 100 parts by weight of the binder resin. The content of the electron transport material is preferably 30 to 200 parts by weight with respect to 100 parts by weight of the binder resin.
Moreover, it is preferable that content of the amine compound represented by the said General formula (2) shall be 1-30 weight part with respect to 100 weight part of charge transport substances represented by the said General formula (1). When the content of this compound is less than 1 part by weight, the decrease in charging and the image blur due to the effects of ozone and NOx are remarkable. On the other hand, when the content is more than 30 parts by weight, the increase in the residual potential due to repeated use increases. .

  The film thickness of the single-layer type photosensitive layer is preferably 50 μm or less, and preferably 25 μm or less from the viewpoint of resolution and responsiveness. The lower limit varies depending on the system to be used (particularly charging potential), but is preferably 5 μm or more.

<Underlayer>
In the photoreceptor of the present invention, an undercoat layer (not shown) can be provided between the conductive support 31 and the photosensitive layer. In general, the undercoat layer is mainly composed of a resin. However, considering that the photosensitive layer is coated with a solvent on these resins, it is desirable that the resin be a resin having a high solvent resistance with respect to a general organic solvent. . Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. Further, fine powder pigments of metal oxides such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, and indium oxide may be added to the undercoat layer in order to prevent moire and reduce residual potential.

These undercoat layers can be formed using an appropriate solvent and a coating method like the above-mentioned photosensitive layer. Also, as the undercoat layer of the present invention, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used, or Al ₂ O ₃ provided by anodization, polyparaxylylene (parylene) ) And other organic substances such as SiO ₂ , SnO ₂ , TiO ₂ , ITO, and CeO ₂ provided by a vacuum thin film forming method can also be used favorably. Further, other known ones can also be used. The thickness of the undercoat layer is suitably from 0 to 5 μm.

<Protective layer>
In the photoreceptor of the present invention, the protective layer 39 may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer. Materials used for the protective layer 39 are ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, aryl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene. , Polybutylene terephthalate, polycarbonate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, polyarylate, AS resin, butadiene-styrene copolymer, polyurethane, poly Examples thereof include resins such as vinyl chloride, polyvinylidene chloride, and epoxy resin. From the viewpoint of filler dispersibility, residual potential, and coating film defects, polycarbonate or polyarylate is particularly effective and useful.
In addition, a filler material can be added to the protective layer of the photoreceptor for the purpose of improving the wear resistance.

  Moreover, the amine compound represented by the said General formula (2) may be contained in the protective layer. Further, the addition of the charge transport material mentioned in the charge transport layer 37 is effective and useful for reducing the residual potential and improving the image quality.

As a method for forming the protective layer, conventional methods such as dip coating, spray coating, beat coating, nozzle coating, spinner coating, ring coating, etc. can be used. preferable.
As the solvent used for forming the protective layer, all solvents used in the charge transport layer 37 such as tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, and acetone can be used. However, a solvent having a high viscosity is preferable at the time of dispersion, but a solvent having high volatility is preferable at the time of coating. When there is no solvent satisfying these conditions, it is possible to use a mixture of two or more solvents having respective physical properties, which may have a great effect on filler dispersibility and residual potential. .

<Intermediate layer>
In the photoreceptor of the present invention, an intermediate layer can be provided between the photosensitive layer and the protective layer. In the intermediate layer, a binder resin is generally used as a main component. Examples of these resins include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. As a method for forming the intermediate layer, a generally used coating method as described above is employed. In addition, about 0.05-2 micrometers is suitable for the thickness of an intermediate | middle layer.

<Additives>
In the present invention, in order to improve environmental resistance, in order to prevent a decrease in sensitivity and an increase in residual potential, oxidation is performed on each layer such as a charge generation layer, a charge transport layer, an undercoat layer, a protective layer, and an intermediate layer. Inhibitors, plasticizers, lubricants, UV absorbers and leveling agents can be added. Representative materials of these compounds are described below.

(Antioxidant)
Examples of the antioxidant that can be added to each layer include, but are not limited to, the following.
(A) Phenolic compounds 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, n-octadecyl -3- (4'-hydroxy-3 ', 5'-di-t-butylphenol), 2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2,2'- Methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4′-thiobis- (3-methyl-6-tert-butylphenol), 4,4′-butylidenebis- (3-methyl) -6-tert-butylphenol), 1,1,3-tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6- Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [meth -3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis (4′-hydroxy-3′-t-butylphenyl) ) Butyric acid] cricol ester, tocopherols and the like.

(B) Paraphenylenediamines N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylene Diamine, N, N′-di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.

(C) Hydroquinones 2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2 -(2-octadecenyl) -5-methylhydroquinone and the like.

(D) Organic sulfur compounds Dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, and the like.

(E) Organic phosphorus compounds Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine and the like.

(Plasticizer)
Examples of the plasticizer that can be added to each layer include, but are not limited to, the following.
(A) Phosphate ester plasticizer Triphenyl phosphate, tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, trichloroethyl phosphate, cresyl diphenyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate, Triphenyl phosphate etc.

(B) Phthalate ester plasticizers Dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dibutyl phthalate, diheptyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, di-n-octyl phthalate, phthalate Dinonyl acid, diisononyl phthalate, diisodecyl phthalate, diundecyl phthalate, ditridecyl phthalate, dicyclohexyl phthalate, butyl benzyl phthalate, butyl lauryl phthalate, methyl oleyl phthalate, octyl decyl phthalate, dibutyl fumarate, dioctyl fumarate Such.

(C) Aromatic carboxylic acid ester plasticizers Trioctyl trimellitic acid, tri-n-octyl trimellitic acid, octyl oxybenzoate, and the like.

(D) Aliphatic dibasic ester plasticizer dibutyl adipate, di-n-hexyl adipate, di-2-ethylhexyl adipate, di-n-octyl adipate, adipic acid n-octyl-n-decyl , Diisodecyl adipate, dicapryl adipate, di-2-ethylhexyl azelate, dimethyl sebacate, diethyl sebacate, dibutyl sebacate, di-n-octyl sebacate, di-2-ethylhexyl sebacate, di-2 sebacate -Ethoxyethyl, dioctyl succinate, diisodecyl succinate, dioctyl tetrahydrophthalate, di-n-octyl tetrahydrophthalate and the like.

(E) Fatty acid ester derivatives butyl oleate, glycerin monooleate, methyl acetylricinoleate, pentaerythritol ester, dipentaerythritol hexaester, triacetin, tributyrin and the like.

(F) Oxyacid ester plasticizers Methyl acetyl ricinoleate, butyl acetyl ricinoleate, butyl phthalyl butyl glycolate, tributyl acetyl citrate and the like.

(G) Epoxy plasticizer Epoxidized soybean oil, epoxidized linseed oil, butyl epoxy stearate, decyl epoxy stearate, octyl epoxy stearate, benzyl epoxy stearate, dioctyl epoxy hexahydrophthalate, didecyl epoxy hexahydrophthalate, etc. .

(H) Dihydric alcohol ester plasticizers such as diethylene glycol dibenzoate and triethylene glycol di-2-ethylbutyrate.

(I) Chlorinated plasticizer Chlorinated paraffin, chlorinated diphenyl, chlorinated fatty acid methyl, methoxychlorinated fatty acid methyl and the like.

(J) Polyester plasticizer Polypropylene adipate, polypropylene sebacate, polyester, acetylated polyester and the like.

(K) Sulfonic acid derivatives p-toluenesulfonamide, o-toluenesulfonamide, p-toluenesulfoneethylamide, o-toluenesulfoneethylamide, toluenesulfone-N-ethylamide, p-toluenesulfone-N-cyclohexylamide and the like.

(L) Citric acid derivatives Triethyl citrate, triethyl acetylcitrate, tributyl citrate, tributyl acetylcitrate, tri-2-ethylhexyl acetylcitrate, acetylcitrate-n-octyldecyl, and the like.

(M) Others Terphenyl, partially hydrogenated terphenyl, camphor, 2-nitrodiphenyl, dinonylnaphthalene, methyl abietate and the like.

(Lubricant)
Examples of the lubricant that can be added to each layer include, but are not limited to, the following.
(A) Hydrocarbon compounds Liquid paraffin, paraffin wax, microwax, low-polymerized polyethylene and the like.

(B) Fatty acid compounds Lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid and the like.

(C) Fatty acid amide compounds Stearylamide, palmitylamide, oleinamide, methylenebisstearamide, ethylenebisstearamide and the like.

(D) Ester compounds Lower alcohol esters of fatty acids, polyhydric alcohol esters of fatty acids, fatty acid polyglycol esters, and the like.

(E) Alcohol compounds Cetyl alcohol, stearyl alcohol, ethylene glycol, polyethylene glycol, polyglycerol and the like.

(F) Metal soap Lead stearate, cadmium stearate, barium stearate, calcium stearate, zinc stearate, magnesium stearate and the like.

(G) Natural wax Carnauba wax, candelilla wax, beeswax, whale wax, ivotaro, montan wax and the like.

(H) Others Silicone compounds, fluorine compounds, etc.

(UV absorber)
Examples of the ultraviolet absorber that can be added to each layer include, but are not limited to, the following.
(A) Benzophenone series 2-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,2 ′, 4-trihydroxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2,2′-dihydroxy-4- Such as methoxybenzophenone.

(B) Salsylate type Phenyl salsylate, 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, and the like.

(C) Benzotriazole series (2′-hydroxyphenyl) benzotriazole, (2′-hydroxy5′-methylphenyl) benzotriazole, (2′-hydroxy5′-methylphenyl) benzotriazole, (2′-hydroxy3) '-Tertiarybutyl 5'-methylphenyl) 5-chlorobenzotriazole and the like.

(D) Cyanoacrylate-based ethyl-2-cyano-3,3-diphenyl acrylate, methyl 2-carbomethoxy-3- (paramethoxy) acrylate, and the like.

(E) Quencher (metal complex)
Nickel (2,2′thiobis (4-t-octyl) phenolate) normal butylamine, nickel dibutyldithiocarbamate, nickel dibutyldithiocarbamate, cobalt dicyclohexyldithiophosphate and the like.

(F) HALS (hindered amine)
Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3 5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6 6-tetramethylpyridine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione, 4-benzoyloxy- 2,2,6,6-tetramethylpiperidine and the like.

[Electrophotographic apparatus, electrophotographic method]
The electrophotographic apparatus according to the present invention includes the above-described electrophotographic photosensitive member, a charging unit that charges the surface of the electrophotographic photosensitive member, an image exposing unit that forms an electrostatic latent image on the surface of the electrophotographic photosensitive member, A developing unit that develops an electrostatic latent image to form a toner image; and a transfer unit that transfers the toner image to a recording material. The image forming apparatus further includes other units that are appropriately selected as necessary. Do it. Examples of other means include cleaning means, static elimination means, recycling means, and control means.

<First Embodiment>
Next, the electrophotographic apparatus and the electrophotographic method according to the present invention will be described in detail using specific examples with reference to the drawings.
FIG. 5 is a schematic diagram for explaining the electrophotographic apparatus and the electrophotographic method of the present invention, and is a schematic diagram showing the configuration of the electrophotographic apparatus according to the first embodiment of the present invention.
In FIG. 5, a photoreceptor 1 is the above-described electrophotographic photoreceptor according to the present invention. The photosensitive member 1 has a drum shape, but may be a sheet shape or an endless belt shape.
In the embodiment shown in FIG. 5, the drum-shaped photoreceptor 1 is rotated counterclockwise in the figure by a driving means (not shown), and an image is formed by an electrophotographic method by each means provided around the photoreceptor 1. The Hereinafter, description will be given in the order of each step of the electrophotographic method.
First, the surface of the photoreceptor 1 is uniformly charged by a charging charger 3 as a charging unit. The charging charger 3 may be appropriately selected from conventionally known ones according to the characteristics of the photosensitive member 1 and the developing toner. The surface of the photosensitive member 1 is set to a predetermined potential with a predetermined polarity (positive charging or negative charging). Any one that can be charged is applicable. Examples of the charging charger 3 include a corotron, a scorotron, a solid state charger (solid state charger), a charging roller, and the like.

  Next, an electrostatic latent image is formed on the surface of the uniformly charged photoreceptor 1 by an image exposure unit 5 as an image exposure unit. As the image exposure unit 5, for example, fluorescent materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and electroluminescence (EL) can be used. It is preferable to use a light emitting diode or a semiconductor laser. In order to irradiate only light in a desired wavelength range during image exposure, various filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter are used. It can be disposed between the photoreceptor 1 and the image exposure unit 5.

  The electrostatic latent image formed on the surface of the photoreceptor 1 is developed by a developing unit 6 as developing means using toner. That is, the electrostatic latent image is developed by the developing unit 6 to form a visible toner image. The developing unit 6 may be appropriately selected from conventionally known developing units according to the toner to be used. Examples of the developing unit 6 include a one-component developing method and a two-component developing method, and further, there are ones for magnetic toner and non-magnetic toner, respectively.

  Further, the toner image carried on the photoreceptor 1 is conveyed to a transfer charger 10 as a transfer unit as the photoreceptor 1 rotates. As the transfer charger 10, the same one as the above-described charging charger 3 can be applied, but a combination of the transfer charger 10 and the separation charger 11 as shown in FIG. 5 is effective. Further, in order to improve the transfer efficiency, it is preferable to provide a pre-transfer charger 7 upstream of the transfer charger 10 (relative to the rotation direction of the photosensitive member 1) and precharge the toner image. As the transfer charger 7, the same one as the above-described charging charger 3 can be applied.

On the other hand, at a position where the photoreceptor 1 and the transfer charger 10 face each other, a transfer paper 9 as a recording material is conveyed by a registration roller 8 or the like so that a toner image is transferred to a desired position on the transfer paper 9. The
The toner image is transferred to the transfer paper 9 by the transfer charger 10 at a position where the toner image on the photoreceptor 1 and the transfer paper 9 face each other.
The transfer paper 9 onto which the toner image has been transferred reaches the separation claw 12 by rotating with the photosensitive member 1 and is separated from the surface of the photosensitive member 1 by the separation claw 12, and further description is omitted. Then, it is discharged out of the electrophotographic apparatus through a fixing process.

  Here, on the surface of the photosensitive member 1 after transfer by the transfer charger 10 and separation of the transfer paper 9 by the separation claw 12, toner images that could not be transferred onto the transfer paper 9, so-called transfer residual toner, paper dust, etc. There are deposits. For this reason, deposits are removed from the surface of the photoreceptor 1 by the fur brush 14 and the cleaning blade 15 which are cleaning means. As the cleaning means, in addition to the fur brush 14 and the cleaning blade 15, conventionally known ones such as a mag fur brush can be used. Further, only the fur brush or only the cleaning blade can be used. In order to improve the cleaning efficiency, it is preferable to precharge by the pre-cleaning charger 13 before using the cleaning means. As the pre-cleaning charger 13, the same one as the above-described charging charger 3 can be applied.

The photosensitive member 1 from which the deposits have been removed from the surface by the cleaning means is further discharged by irradiating light from the charge removing lamp 2 as a charge removing means, thereby completing a series of image forming processes by the electrophotographic method. By repeating this series of electrophotographic image forming processes, it is possible to form images on a plurality of recording materials.
Conventionally known means can be used as the charge eliminating means. For example, the charge removing lamp 2 can be the same as the image exposure unit 5 described above.

In the image forming process by the series of electrophotographic methods described above, a positive (negative) electrostatic latent image is formed on the surface of the photoreceptor 1 when the electrophotographic photoreceptor 1 is positively (negatively) charged and image exposure is performed. Is formed. If this is developed with negative (positive) toner, a positive image can be obtained, and if developed with positive (negative) toner, a negative image can be obtained. The charging polarity of the electrophotographic photoreceptor 1 and the polarity of the toner used for development are arbitrary, and any may be used.
Further, the various light sources used in the image exposure unit 5 are not limited to being used in the form shown in FIG. 5, and other than that, a transfer process, a static elimination process, a cleaning process, or a previous process using light irradiation together. It can be used for processes such as exposure.

<Second Embodiment>
FIG. 6 is a schematic diagram showing the configuration of the electrophotographic apparatus according to the second embodiment of the present invention.
The photosensitive member 21 has at least a photosensitive layer (not shown), is driven by driving rollers 22a and 22b, is charged by a charger 23 as charging means, and is exposed and developed by a light source 24 as image exposure means. Development (not shown), transfer using a transfer charger 25 as a transfer means, exposure before cleaning with a light source 26, cleaning with a cleaning brush 27 as a cleaning means, and static elimination with a light source 28 as a static elimination means are repeated. In FIG. 6, the photoconductor 21 (of course, the support is translucent in this case) is irradiated with pre-cleaning exposure light from the conductive support (not shown) side.

The image forming process by the electrophotographic method performed using the electrophotographic apparatus shown in FIG. 6 exemplifies the embodiment in the present invention, and it goes without saying that other embodiments are possible. For example, in FIG. 6, the pre-cleaning exposure is performed from the conductive support (not displayed) side, but this may be performed from the photosensitive layer (not displayed) side. Irradiation may be performed from the conductive support side.
On the other hand, as the process of irradiating light, image exposure, pre-cleaning exposure, and static elimination exposure are illustrated, but in addition, there are provided pre-transfer exposure, pre-exposure of image exposure, and other known light irradiation processes. Thus, the photosensitive member 21 can be irradiated with light.

<Third Embodiment>
Furthermore, an embodiment of an electrophotographic printer (hereinafter simply referred to as a printer) will be described as a full-color electrophotographic apparatus to which the present invention is applied.
FIG. 7 is a schematic view showing the configuration of the electrophotographic apparatus according to the third embodiment of the present invention. In FIG. 7, a drum-shaped photoconductor 56 as a latent image carrier is uniformly charged by a charging charger 53, which is a charging means using a corotron or a scorotron, while being rotated counterclockwise in the figure. After that, the electrostatic latent image is carried by receiving scanning of laser light L emitted from a laser optical device which is an image exposure means (not shown). Since this scanning is performed based on single-color image information obtained by decomposing a full-color image into yellow, magenta, cyan, and black color information, a single-color electrostatic image of yellow, magenta, cyan, or black is formed on the photosensitive drum 56. A latent image is formed. A revolver developing unit 50 is disposed on the left side of the photosensitive drum 56 in the drawing. This has a yellow developing unit, a magenta developing unit, a cyan developing unit, and a black developing unit as developing means in a rotating drum-shaped casing, and each developing unit is opposed to the photosensitive drum 56 by rotation. Move sequentially to development position. The yellow developer, magenta developer, cyan developer, and black developer are for developing an electrostatic latent image by attaching yellow toner, magenta toner, cyan toner, and black toner, respectively. An electrostatic latent image for yellow, magenta, cyan, and black is sequentially formed on the photosensitive drum 56, and these images are sequentially developed by the developing units of the revolver developing unit 50, so that a yellow toner image, a magenta toner image, and a cyan toner are developed. A toner image and a black toner image are obtained.

  An intermediate transfer unit is disposed on the downstream side of the photosensitive drum 56 from the development position. This is because the intermediate transfer belt 58 stretched by a tension roller 59a, an intermediate transfer bias roller 57 as a transfer means, a secondary transfer backup roller 59b, and a belt drive roller 59c is driven by rotation of the belt drive roller 59c. Move endlessly clockwise. The yellow toner image, magenta toner image, cyan toner image, and black toner image developed on the photosensitive drum 56 enter an intermediate transfer nip where the photosensitive drum 56 and the intermediate transfer belt 58 are in contact with each other. Then, while being influenced by the bias from the intermediate transfer bias roller 57, it is superimposed on the intermediate transfer belt 58 and intermediately transferred (primary transfer) to form a four-color superimposed toner image.

  The surface of the photosensitive drum 56 that has passed through the intermediate transfer nip with rotation is cleaned of residual toner by a drum cleaning unit 55 that is a cleaning unit. The drum cleaning unit 55 cleans the transfer residual toner by a cleaning roller to which a cleaning bias is applied, but a cleaning brush made of a fur brush, a mag fur brush, or a cleaning blade may be used. .

  The surface of the photosensitive drum 56 from which the transfer residual toner has been cleaned is neutralized by a neutralizing lamp 54 serving as a neutralizing unit. As the charge removal lamp 54, a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), an electroluminescence (EL), or the like is used. A semiconductor laser is used as the light source of the laser optical device. About these emitted lights, you may make it use only a desired wavelength range by various filters, such as a sharp cut filter, a band pass filter, a near-infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter.

  On the other hand, the registration roller pair 61 that sandwiches the transfer paper 60 that is a recording material fed from a paper feed cassette (not shown) between the two rollers has a four-color superimposed toner image on the intermediate transfer belt 58. Are fed toward the secondary transfer nip where the intermediate transfer belt 58 and the transfer belt 62 are in contact with each other. The four-color superimposed toner images on the intermediate transfer belt 58 are collectively transferred onto the transfer paper 60 under the influence of the secondary transfer bias from the paper transfer bias roller 63 as the secondary transfer means in the secondary transfer nip. Secondary transferred. A full color image is formed on the transfer paper 60 by this secondary transfer. The transfer paper 60 on which the full-color image is formed is sent to the transport belt 64 by the transfer belt 62. The conveyor belt 64 feeds the transfer paper 60 received from the transfer unit into the fixing unit 65. The fixing unit 65 conveys the transferred transfer paper 60 while being sandwiched between fixing nips formed by contact between the heating roller and the backup roller. The full-color image on the transfer paper 60 is fixed on the transfer paper 60 under the influence of heating from the heating roller and pressure applied in the fixing nip.

  Although not shown, a bias for adsorbing the transfer paper 60 is applied to the transfer belt 62 and the conveyance belt 64. In addition, a paper neutralization charger that neutralizes the transfer paper 60 and three belt neutralization chargers that neutralize each belt (intermediate transfer belt 58, transfer belt 62, and conveyance belt 64) are provided. The intermediate transfer unit also includes a belt cleaning unit having the same configuration as that of the drum cleaning unit 55, thereby cleaning the transfer residual toner on the intermediate transfer belt 58.

That is, the electrophotographic apparatus of the present invention includes an intermediate transfer unit in addition to the transfer unit that transfers to the intermediate transfer member, and the toner image formed on the electrophotographic photosensitive member by the transfer unit is transferred to the intermediate transfer unit. It is possible to adopt a configuration in which an image is formed on an intermediate transfer member by primary transfer to a medium, and the image on the intermediate transfer member is secondarily transferred onto the recording material by the intermediate transfer unit.
Here, when the image that is secondarily transferred onto the recording material is a color image composed of a plurality of colors of toner, the toner of each color is sequentially superimposed on the intermediate transfer member by the transfer means. An image can be formed on the body, and the image on the intermediate transfer body can be secondarily transferred collectively onto the recording material by the intermediate transfer unit.

<Fourth embodiment>
FIG. 8 is a schematic diagram showing the configuration of the electrophotographic apparatus according to the fourth embodiment of the present invention. This embodiment is a tandem type electrophotographic apparatus having an intermediate transfer belt 87, and does not share the photosensitive drum 80 for each color, but includes photosensitive drums 80Y, 80M, 80C, and 80Bk for each color. Yes. Further, a developing unit (developing unit) 82, a drum cleaning unit (cleaning unit) 85, a static elimination lamp (static elimination unit) 83, a charging roller (charging unit) 84 for uniformly charging the drum, and a bias roller (primary transfer unit) 86 are also provided. , For each color.

In the printer shown in FIG. 7, the charging charger 53 is provided as the drum uniform charging means, but in this apparatus, the charging roller 84 is provided. A fur brush 94 is provided as a belt cleaning unit for cleaning the intermediate transfer belt 87.
In addition, a registration roller pair 88, a paper 89 as a recording material, a paper transfer bias roller 90 as a secondary transfer means, a transfer belt 91, a transport belt 92, and a fixing unit 93 are disposed. Since it overlaps with the embodiment, the description is omitted.
In the tandem method, latent image formation (image exposure process) and development of each color can be performed in parallel, so that the image formation speed can be much faster than the revolver method.

<Process cartridge>
The image forming apparatus as described above may be fixedly incorporated in a copying apparatus, facsimile, or printer, but may be incorporated in these apparatuses in the form of a process cartridge. A process cartridge is a single device (part) that contains a photosensitive member and includes at least one means selected from a charging means, an image exposure means, a developing means, a transfer means, a cleaning means, and a static elimination means. .
The process cartridge has various shapes and the like, and a general example is shown in FIG.

FIG. 9 is a schematic diagram showing the configuration of an embodiment of a process cartridge according to the present invention.
In the present embodiment, an electrophotographic photosensitive member 16, a charging charger 17 as a charging unit, an image exposing unit 19 as an image exposing unit, a developing roller 20 as a developing unit, and a cleaning brush 18 as a cleaning unit. It comprises.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not restrict | limited by an Example. All parts are parts by weight.

[Example 1]
An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition are sequentially applied onto an aluminum cylinder by dip coating and dried to obtain a 3.5 μm undercoat layer, 0. A 2 μm charge generation layer and a 23 μm charge transport layer were formed. 1 was produced.

(Undercoat layer coating solution)
Titanium dioxide powder (Ishihara Sangyo Co., Ltd., Tybak CR-EL): 400 parts Melamine resin (Dainippon Ink Co., Ltd., Super Becamine G821-60): 65 parts Alkyd resin (Dainippon Ink Co., Ltd., Beckolite M6401-50) ): 120 parts 2-butanone: 400 parts

(Charge generation layer coating solution)
Fluorenone bisazo pigment having the following structure: 12 parts

Polyvinyl butyral (manufactured by Union Carbide, XYHL): 5 parts 2-butanone: 200 parts cyclohexanone: 400 parts

(Charge transport layer coating solution)
Polycarbonate resin (Z Polyca, manufactured by Teijin Chemicals Ltd.): 10 parts Charge transport material of 5: 9 parts Amine compound of the above formula (2a): 1 part Tetrahydrofuran: 100 parts

The electrophotographic photosensitive member produced as described above is mounted on an electrophotographic process cartridge and mounted on a tandem full-color digital copier (Imagio MPC7500 manufactured by Ricoh). In addition, a printing durability test was performed to print a total of 100,000 sheets using 5% characters as an image area on average. At that time, the initial image and the image after the printing durability test, the exposure portion potential (VL), and the fluctuation in the job were evaluated.
In order to evaluate the variation within the job, first, the exposed portion potential (VL) of the photoconductor is measured using a surface potentiometer, and then the continuous printing of 50 sheets is set to 1 Job, and this is repeated 10 times, and then the exposed portion potential is set again. Measurement was performed, and <VL after repeated printing>-<first VL> was evaluated as variation within the job. In addition to the measured values, Table 1 shows the determination result as to whether or not the range is correctable for use in the process.

・ Judgment criteria for fluctuation within job ◎: Level that does not cause any problem ○: Level that changes slightly, but does not cause a problem within the range that can be corrected △: Level that changes are clearly recognized and slightly exceeds the allowable range ×: Large change , Problematic level

[Examples 2 to 10]
In Example 1, Exemplified Compound No. 5 except that the compounds shown in Table 3 were used instead of the charge transport material (CTM) 5 and the amine compound of the formula (2a). 2 to 10 were prepared and evaluated. The results are also shown in Table 3.

[Examples 11 to 13]
Electrophotographic photoreceptors Nos. 11 to 13 were produced in the same manner as in Example 1 except that the charge generation layer coating solution and the charge transport layer coating solution were changed to the following in Example 1. The charge transport materials (CTM) and amine compounds of the exemplified compounds were those shown in Table 4. The evaluation results are also shown in Table 4.

(Charge generation layer coating solution)
Titanyl phthalocyanine having powder XD spectrum shown in FIG. 10: 8 parts Polyvinyl butyral (BX-1, manufactured by Sekisui Chemical Co., Ltd.): 5 parts 2-butanone: 400 parts

(Charge transport layer coating solution)
Polycarbonate resin (Z Polyca, manufactured by Teijin Chemicals Ltd.): 10 parts Charge transport material (CTM) of exemplary compound: 8 parts Amine compound: 0.5 part Tetrahydrofuran: 100 parts

[Examples 14 to 16]
Electrophotographic photoreceptors Nos. 14 to 16 were produced in the same manner as in Example 11 except that the charge transport layer coating solution in Example 11 was changed to the following. The charge transport materials and amine compounds of the exemplified compounds were those shown in Table 5.

(Charge transport layer coating solution)
Polycarbonate resin (Z Polyca, manufactured by Teijin Chemicals Ltd.): 10 parts Charge transport material (CTM) of exemplary compound: 8 parts Amine compound: 2 parts Tetrahydrofuran: 100 parts

[Examples 17 to 24]
In Example 1, Exemplified Compound No. The electrophotographic photosensitive members No. 17 to 24 were prepared and evaluated in the same manner except that the charge transport material of No. 5 was changed to Exemplified compounds 2, 4, 7, 8, 10, 11, 12, and 13, respectively. The same effect as in Example 1 was obtained.

[Comparative Example 1]
An electrophotographic photoreceptor No. 25 was prepared and evaluated in the same manner as in Example 1 except that the amine compound of formula (2a) was not added in Example 1. The results are shown in Table 6.

[Comparative Example 2]
In Example 1, an electrophotographic photoreceptor No. 26 was prepared and evaluated in the same manner as in Example 1 except that the compound of the following structural formula (4) was used instead of the amine compound of the formula (2a). The results are shown in Table 6.

[Comparative Example 3]
In Example 1, electrophotographic photoreceptor No. 27 was prepared and evaluated in the same manner as in Example 1 except that the compound of the following structural formula (5) was used instead of the amine compound of formula (2a). The results are shown in Table 6.

[Comparative Example 4]
In Example 1, electrophotographic photoreceptor No. 28 was prepared and evaluated in the same manner as in Example 1 except that the compound of the following structural formula (6) was used instead of the amine compound of formula (2a). The results are shown in Table 6.

[Comparative Example 5]
In Example 1, electrophotographic photoreceptor No. 29 was prepared and evaluated in the same manner as in Example 1 except that the compound of the following structural formula (7) was used instead of the amine compound of formula (2a). The results are shown in Table 6.

[Comparative Example 6]
An electrophotographic photoreceptor No. 30 was prepared and evaluated in the same manner as in Example 11 except that the charge transport material of the exemplary compound in Example 11 was changed to the compound of the following structural formula (8). The results are shown in Table 7.

[Comparative Example 7]
An electrophotographic photoreceptor No. 31 was prepared and evaluated in the same manner as in Example 11 except that the charge transport material of the exemplary compound in Example 11 was changed to the compound of the following structural formula (9). The results are shown in Table 7.

[Comparative Example 8]
An electrophotographic photoreceptor No. 32 was prepared and evaluated in the same manner as in Example 11 except that the charge transport material of the exemplary compound in Example 11 was changed to the compound of the following structural formula (10). The results are shown in Table 7.

As seen in Examples 1 to 24, the photoconductor of the present invention has stable photoconductor characteristics even after repeated use over a long period of time, and image deterioration such as image density reduction and image blurring does not occur. Furthermore, there is little fluctuation in the job and it does not increase much even after repeated use.
On the other hand, in the case of Comparative Example 1 which does not contain the amine compound represented by the general formula (2) and Comparative Examples 2 to 4 using other amine compounds other than the amine compound represented by the general formula (2) The initial image quality is good, but image deterioration due to repeated use cannot be suppressed.
When the amine compound of Comparative Example 5 is used, a good image can be obtained even after repeated use. However, variation within the job cannot be suppressed, and in the case where the same image is output continuously, the image density and color tone Changes will occur.
Comparative Examples 6 to 8 are cases where combined with other charge transport materials, and image degradation after repeated use is slight, but in this case as well, fluctuations within the Job cannot be suppressed.

As described above, according to the present invention, there is provided an electrophotographic photoreceptor in which the photoreceptor characteristics are stable even when used repeatedly for a long time, the fluctuation in the job is suppressed, and a high-quality image can be stably obtained over a long period. be able to.
In addition, according to the present invention, an electrophotographic method, an electrophotographic apparatus, and an electrophotographic apparatus that can output an image with little change in image density and color, that is, excellent image quality consistency, by using the electrophotographic photosensitive member. An apparatus process cartridge is provided. As a result, it is possible to cope with higher durability and higher stability of the organic photoreceptor required from the general office area to the SOHO area or the light printing area.

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Static elimination lamp 3 Charge charger 5 Image exposure part 6 Developing unit 7 Pre-transfer charger 8 Registration roller 9 Transfer paper 10 Transfer charger 11 Separation charger 12 Separation claw 13 Pre-cleaning charger 14 Fur brush 15 Cleaning brush 16 Photoconductor 17 Charging Charger 18 Cleaning brush 19 Image exposure unit 20 Developing roller 21 Photoconductor 22a, 22b Driving roller 23 Charging charger 24 Image exposure source 25 Transfer charger 26 Pre-cleaning exposure light source 27 Cleaning brush 28 Static elimination light source 31 Conductive support 33 Photosensitive layer 35 Charge Generation layer 37 Charge transport layer 39 Protective layer 50 Revolver development unit 53 Charge charge 54 Static elimination lamp 55 Drum cleaning unit 56 Photoconductor 57 Bias roller 58 Intermediate transfer belt 9a tension roller 59b backup roller 59c belt driving roller 60 the transfer sheet 61 registration rollers 62 transfer belt 63 the paper transfer bias roller 64 the conveyor belt 65 fixing unit 80 the photosensitive drum (photosensitive member)
80Y, 80M, 80C, 80Bk Photosensitive drum 81 Exposure light source 82 Development unit 83 Static elimination lamp 84 Charging roller 85 Drum cleaning unit 86 Intermediate transfer belt 87 Intermediate transfer belt 88 Registration roller 89 Paper 90 Paper transfer bias roller 91 Transfer belt 92 Transport belt 93 Fixing Unit 94 Fur Brush

Japanese Unexamined Patent Publication No. 01-230055 Japanese Patent Laid-Open No. 03-172852 JP 2002-333731 A Japanese Patent Laid-Open No. 04-56866 Japanese Patent No. 4101676 JP 2009-42564 A

Claims (9)

An electrophotographic photoreceptor having at least a photosensitive layer on a conductive support, wherein the photosensitive layer comprises a charge transport material represented by the following general formula (1) and an amine compound represented by the following general formula (2): An electrophotographic photosensitive member containing the electrophotographic photosensitive member.

(In the formula, R ₁ and R ₂ represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, and at least one of R ₁ and R ₂ is a substituted or unsubstituted aryl group.)

(In the formula, A and B are selected from the following (i) and (ii), respectively, and may be the same or different.
(I) _-CH 2 X
_(Ii) -CH 2 _CH 2 Y
However, X and Y each represent an aromatic residue, and these may have a substituent. )   A charging step for charging the surface of the electrophotographic photosensitive member, an image exposing step for forming an electrostatic latent image on the electrophotographic photosensitive member, a developing step for developing the electrostatic latent image to form a toner image, The electrophotographic method according to claim 1, wherein the electrophotographic method is such that the toner image is directly transferred to a recording material or a transfer step of transferring the toner image to a recording material via an intermediate transfer member is repeated. An electrophotographic method using a photoconductor.   The electrophotographic method is a digital method, and the image exposing step forms an electrostatic latent image on the electrophotographic photosensitive member by light irradiation using a semiconductor laser (LD) or a light emitting diode (LED) as a light source. The electrophotographic method according to claim 2, wherein the electrophotographic method is provided.   An electrophotographic photosensitive member; a charging unit that charges the surface of the electrophotographic photosensitive member; an image exposing unit that forms an electrostatic latent image on the surface of the electrophotographic photosensitive member; and a toner image obtained by developing the electrostatic latent image 2. An electrophotographic apparatus comprising: a developing unit that forms a toner image; and a transfer unit that directly transfers the toner image to a recording material or transfers it to an intermediate transfer member, wherein the electrophotographic photosensitive member is defined in claim 1. An electrophotographic apparatus which is an electrophotographic photosensitive member.   The electrophotographic apparatus is a digital system, and the image exposure means uses a semiconductor laser (LD) or a light emitting diode (LED) that forms an electrostatic latent image on the surface of the electrophotographic photosensitive member as a light source. The electrophotographic apparatus according to claim 4, wherein the apparatus is an electrophotographic apparatus.   6. The electrophotographic apparatus according to claim 4, wherein the electrophotographic photosensitive member, the charging unit, the developing unit, and the transfer unit have a tandem configuration including a plurality of image forming elements. apparatus.   It comprises transfer means for primary transfer of the toner image on the electrophotographic photosensitive member to an intermediate transfer body, and transfer means for secondary transfer of the toner image formed on the intermediate transfer body onto the recording material. An electrophotographic apparatus according to any one of claims 4 to 6.   The image that is secondarily transferred onto the recording material is a color image composed of a plurality of colors of toner, and the primary transfer means sequentially superimposes toner of each color on the intermediate transfer member. 8. The electrophotographic apparatus according to claim 7, wherein an image is formed on the recording material, and the image on the intermediate transfer body is secondarily transferred collectively onto the recording material by the secondary transfer unit.   2. The electrophotographic photosensitive member according to claim 1, charging means for charging the surface of the electrophotographic photosensitive member, image exposure means for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member, and developing the electrostatic latent image And at least one selected from a developing unit for forming a toner image, a cleaning unit for cleaning the surface of the electrophotographic photosensitive member, and a transfer unit for directly transferring the toner image to a recording material or transferring it to an intermediate transfer member. And a process cartridge for an electrophotographic apparatus.

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