JP4462122B2 - Electrophotographic photosensitive member, electrophotographic cartridge, image forming apparatus and image forming method - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member, an electrophotographic cartridge, an image forming apparatus, and an image forming method containing an azo compound having a specific structure.

Electrophotographic technology is widely used not only for conventional copiers but also for various printers, facsimiles, and the like because of its immediacy and high quality images. As for photoconductors that form the core of electrophotographic technology, inorganic photoconductive materials such as amorphous silicon and arsenic-selenium are currently used in part, but the mainstream is organic photoconductors.
Several layer configurations have been devised for organic photoreceptors, but so-called multilayer photoreceptors that separate charge generation and charge transport functions and stack charge generation layers and charge transport layers have a greater degree of design freedom. Since it is high, it has been studied and developed energetically because it can provide a higher-performance photoconductor and has high productivity. At present, the range of use extends to medium and high-speed copying machines and printers. The required characteristics for the photoconductor include basic features such as high photosensitivity, sufficient charging characteristics, low residual potential, good response characteristics, and high stability in repeated use of these characteristics. In addition to these characteristics, various characteristics are required from a practical viewpoint. One of them is light resistance. Usually, the photoconductor is used in a state where it is shielded from light inside a copying machine or a laser printer. However, the photoconductor is necessarily exposed to external light during machine assembly, when a paper jam occurs during use, or when the photoconductor unit reaches the end of its service life or is replaced. Become.

The light intensity of the external light is much stronger than the exposure intensity for image formation in the machine and contains a lot of short wavelength light, which causes great damage to the photoconductor. This is because exposure of the photoconductor to light generates a large amount of charge traps inside the photoconductor, often resulting in a significant increase in residual potential.
The mechanism by which charge traps occur is not well understood. For example, when the charge transport material itself is excited by absorbing the exposed light and relaxes from its excited state, it does not return to the original ground state. If the structure changes to another structure with an intermediate energy state, which causes charge trapping, or the components in the charge transport layer (charge transport material alone or if it contains an electron-withdrawing material) It is believed that weak charge transfer complexes formed with the transport material are directly excited to generate charge carrier pairs, which are responsible for them.

  Until now, in order to prevent such damage, for example, when assembling the machine, a yellow light with less influence is used, or when opening the inside of the machine, a light shielding plate is used to minimize the light exposure to the photoreceptor. It is dealt with by providing it. On the other hand, for example, in order to suppress an increase in residual potential at the time of exposure to light, studies have been made such as adding an electron-withdrawing substance to the charge transport layer or adding an antioxidant. Even with these, the effect of preventing the increase in residual potential was not sufficient. Even if the increase in the residual potential after exposure to light is suppressed, there are problems such as an increase in the residual potential during normal use, an increase in the residual potential during repeated use, and a decrease in chargeability, resulting in increased side effects on other characteristics. there were.

In addition, a method is disclosed in which an orange dye is contained in the photosensitive layer or the surface protective layer to block light of a specific wavelength and to suppress deterioration of the photosensitive member due to light exposure (see, for example, Patent Document 1). However, the photoconductor is composed of various substances such as a charge generation material, a charge transport material, a binder resin, and an antioxidant, and the characteristics as a photoconductor are composed of a balance of many materials, and simply absorb at a specific wavelength. By simply including the compound in the photosensitive layer and protective layer, deterioration of the photoconductor due to light exposure can be suppressed, but the balance of the material that was established before the addition of the dye is lost by adding the dye, and during normal use As a result, there is a drawback that the residual potential increases, the stability during repeated use decreases, and the demerits resulting from side effects become larger than the merits of adding dyes.

As a charge transport material, a photoreceptor using a compound in which an azobenzene skeleton that is a color group is introduced into a known structure such as a hydrazone structure or a triphenylamine structure has been proposed (for example, Patent Document 2). And Japanese Patent Application Laid-Open No. H11-228707), it did not satisfy the performance such as high-speed response that is highly demanded of recent photoreceptors.
JP-A-10-228121 JP-A-3-55558 JP-A-3-64761

  High-performance electrophotographic photosensitive members that can be used for high-speed image formation that has been developed in recent years are susceptible to damage by oxidizing gases such as ozone and NOx, and have low light resistance against external light. In the prior art, no technology has been found to improve durability against exposure to external light without adversely affecting other characteristics of the photoreceptor, and a highly durable electrophotographic photoreceptor is strongly desired. It was. The present invention is a high-performance electrophotographic photosensitive member that has high sensitivity, low residual potential, excellent electrical characteristics and can be used for high-speed image formation, and maintains its performance even when exposed to intense light. An object of the present invention is to provide an electrophotographic photosensitive member having a high durability performance that can be used.

  As a result of intensive studies on an electrophotographic photosensitive member that has little influence on other electrophotographic characteristics and has strong durability against exposure to external light, the present inventors have found an azo compound having a specific structure, By using the azo compound in an electrophotographic photoreceptor, it has been found that an increase in the residual potential of the photoreceptor upon exposure to light can be prevented without affecting various characteristics of the photoreceptor, and the present invention is completed. It came to.

  That is, the gist of the present invention is that, in an electrophotographic photosensitive member having a photosensitive layer on a conductive support, any layer formed on the conductive support is represented by the following general formula (1). An electrophotographic photosensitive member is characterized by containing an azo compound or a compound represented by the following formula (2).

Wherein R ¹ and R ² are alkyl groups having 3 or less carbon atoms that may have a substituent, Ar ¹ is an arylene group having an alkyl group, and Ar ² is an arylene that may have a substituent. Groups Ar ³ and Ar ⁴ represent a phenyl group which may have an alkyl group as a substituent.

Wherein R ³ and R ⁴ are alkyl groups having 2 or less carbon atoms, Ar ⁵ is a phenylene group having an alkyl group, Ar ⁶ is an arylene group which may have a substituent, Ar ⁷ and Ar ⁸ are substituents Represents an optionally substituted aryl group.)

The electrophotographic photoreceptor according to the present invention is an excellent photoreceptor that is easy to handle and exhibits excellent light resistance. In particular, it exhibits a very high effect on a photoreceptor using a polyarylate resin as a binder for a charge transport layer.
The photoconductor according to the present invention hardly accumulates a residual potential even when it is repeatedly used, has little fluctuation in charging potential and sensitivity, has very good stability, and has excellent durability. It can be suitably used for a machine or a color printer.

  The image forming apparatus using the photoconductor and the drum cartridge according to the present invention do not need special measures for light shielding and can be handled easily.

Hereinafter, embodiments of the present invention will be described in detail. However, the description of the constituent elements described below is a representative example of the embodiments of the present invention, and is appropriately modified without departing from the spirit of the present invention. can do.
The electrophotographic photoreceptor of the present invention has a photosensitive layer on a conductive support, and any layer formed on the conductive support is represented by the following general formula (1) or general formula (1) The azo compound represented by 2) is contained.

Wherein R ¹ and R ² are alkyl groups having 3 or less carbon atoms that may have a substituent, Ar ¹ is an arylene group having an alkyl group, and Ar ² is an arylene that may have a substituent. Groups Ar ³ and Ar ⁴ represent a phenyl group which may have an alkyl group as a substituent.

Wherein R ³ and R ⁴ are alkyl groups having 2 or less carbon atoms, Ar ⁵ is a phenylene group having an alkyl group, Ar ⁶ is an arylene group which may have a substituent, Ar ⁷ and Ar ⁸ are substituents Represents an optionally substituted aryl group.)
The azo compound represented by formula (1) and the azo compound represented by formula (2) of the present invention both have an azo skeleton portion represented by C as represented by the following formula (3). In addition, the skeleton has a common structure in that the dialkylamino group part represented by A and the diarylhydrazone group part represented by B are bonded.

(Wherein R ^X and R ^Y are alkyl groups which may have a substituent, and Ar ^m , Ar ⁿ , Ar ^o and Ar ^p have an aryl group or a substituent which may have a substituent. Represents an optionally substituted arylene group.)
An azo compound represented by the formula (3) often has poor solubility in a binder resin used in a general electrophotographic photosensitive member. In this case, the solubility can be improved by increasing the alkyl chain length of the dialkylamino group portion of A. However, although the reason is not clear, if the alkyl chain length of the dialkylamino group portion of A is too long, the chargeability when the electrophotographic photoreceptor is repeatedly used and the residual potential increase, There is a problem that the adverse effect on the characteristics of the electrophotographic photosensitive member is increased. If the alkyl chain length is too long, the solubility in an organic solvent becomes too good, and it becomes difficult to separate the target azo compound from the organic solvent at the time of manufacture, the handleability is significantly reduced, and the purity is improved. The problem of being unable to do so also occurs.

In order to make both the solubility and the electric characteristics of the electrophotographic photosensitive member suitable, the alkyl chain length of the dialkylamino group part of A is set to an appropriate length, and the skeleton part represented by C is used. It is very important that Ar ^m has an alkyl group. This is because, when Ar ^m has an alkyl group, the packing of the azo compound molecules of the present invention is suppressed, the solubility is moderately improved, and the electronic state of the whole molecule does not adversely affect the characteristics of the photoreceptor. It is because it can be in a state. Therefore, Ar ¹ and Ar ⁵ of the azo compound represented by formula (1) or formula (2) of the present invention have an alkyl group.

On the other hand, if the molecular weight of the entire azo compound of the present invention is excessively increased, the molecular design effect cannot be obtained. Therefore, the molecular weight of the entire azo compound of the present invention is usually 520 or less, The molecular weight is preferably 510 or less, and more preferably 500 or less.
In addition, the bonding position of the dialkylamino group part represented by A and the diarylhydrazone group part represented by B to the skeleton part represented by C has absorption in the wavelength region affecting light exposure. For the reason of being in an electronic state, it is preferable that the distance between the dialkylamino group part represented by A and the diarylhydrazone group part represented by B is further increased. In the case where the arylene group optionally having a substituent represented by Ar ^m or Ar ⁿ is a phenylene group optionally having a substituent, it is bonded to the 4-position relative to the diazo group. In the case where the arylene group which may have a substituent represented by Ar ^m or Ar ⁿ is a naphthylene group which may have a substituent, the diazo group is a naphthylene ring. If you are in first place In addition, it is preferable to bond at the 4-position. Hereinafter, the azo compound of the present invention will be described in more detail.
<Azo compound of formula (1)>
The azo compound used in the present invention is first an azo compound having the structure of the following general formula (1).

In formula (1), R ¹ and R ² represent an optionally substituted alkyl group having 3 or less carbon atoms, Ar ¹ represents an arylene group having an alkyl group, and Ar ² has a substituent. Arylene groups, Ar ³ and Ar ⁴ which may be represented by each other represent a phenyl group which may have an alkyl group as a substituent.
R ¹ and R ^{2 in} formula (1) are alkyl groups having 3 or less carbon atoms which may be the same as or different from each other and may have a substituent. And an alkyl group having no substituent such as an ethyl group, a propyl group and an isopropyl group, and a substituted alkyl group having an alkoxy group such as a methoxymethyl group as a substituent. Among these, a linear alkyl group having no substituent is preferable from the viewpoint of production cost and ease of production. When the number of carbon atoms in the alkyl group is large, the molecular weight is increased, and the light exposure to the added amount is reduced. An alkyl group having 2 or less carbon atoms is more preferred because the effect is reduced. R ¹ and R ² may combine with each other to form a ring structure, and may have a structure such as a pyrrolidinyl group or a piperidino group.

Ar ¹ represents an arylene group having an alkyl group. Examples of the arylene group include a phenylene group, a naphthylene group, a biphenylene group, and a terphenylene group. Examples of the alkyl group that the arylene group has include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Considering ease of production and versatility of raw materials, the arylene group preferably has 3 or less aromatic rings, more preferably a phenylene group or a naphthylene group, and particularly preferably a phenylene group. As the alkyl group having the same, in view of ease of production and versatility of raw materials, an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, a propyl group, and an isopropyl group is preferable, and more preferably a carbon number. 1 to 3 alkyl groups, particularly preferably a methyl group.

Ar ² represents an arylene group which may have a substituent. Examples of the arylene group include a phenylene group, a naphthylene group, a biphenylene group, and a terphenylene group. Examples of the substituent that may be included include an alkyl group such as a methyl group, an ethyl group, a propyl group, and an isopropyl group; An alkyl group having a substituent such as a group; an alkoxy group such as a methoxy group, an ethoxy group, and a tertiary butoxy group; Among these, in view of ease of production and versatility of raw materials, the arylene group is preferably a phenylene group or a naphthylene group, and more preferably a phenylene group. And as a substituent which you may have, an alkyl group is preferable in view of ease of production and versatility of raw materials, more preferably 1 to 5 carbon atoms such as a methyl group, an ethyl group, and an isopropyl group. More preferred are alkyl groups of 1 to 3, particularly preferably a methyl group. Ar ¹ and Ar ² may be the same or different from each other.

Ar ³ and Ar ⁴ may be the same or different from each other and each represents a phenyl group which may have an alkyl group as a substituent. In consideration of the versatility of the raw materials and the influence on the electrophotographic photosensitive member, the alkyl group that may be contained is an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, a propyl group, or an isopropyl group. preferable. More preferred are alkyl groups having 1 to 3 carbon atoms such as a methyl group, an ethyl group and an isopropyl group, and particularly preferred is a methyl group.

Ar ³ and Ar ⁴ may be directly bonded to form a ring structure such as carbazole, and are bonded via a bridging atom such as a nitrogen atom, an oxygen atom, or a sulfur atom, and phenothiazine, phenoxazine, xanthene Or a ring structure may be formed by bonding to each other via a divalent organic residue.
<Azo compound of formula (2)>
The azo compound used in the present invention is secondly an azo compound having the structure of the following general formula (2).

In the formula (2), R ³ and R ⁴ are alkyl groups having 2 or less carbon atoms, Ar ⁵ is a phenylene group having an alkyl group, Ar ⁶ is an arylene group which may have a substituent, Ar ⁷ , Ar ⁸ Represents an aryl group which may have a substituent.
R ³ and R ⁴ in the formula (2) are alkyl groups having 2 or less carbon atoms, and specific examples thereof include a methyl group and an ethyl group. R ³ and R ⁴ may be bonded to each other to form a ring structure, and may have a structure such as a pyrrolidinyl group.

Ar ⁵ represents a phenylene group having an alkyl group. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and an isopropyl group, but considering the versatility of the raw material, an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, and an isopropyl group. Group is preferable, more preferably an alkyl group having 1 to 3 carbon atoms, and particularly preferably a methyl group.
Ar ⁶ represents an arylene group which may have a substituent, and as the arylene group,
Examples thereof include a phenylene group, a naphthylene group, a biphenylene group, and a terphenylene group. Examples of the substituent that the arylene group may have include an alkyl group such as a methyl group, an ethyl group, a propyl group, and an isopropyl group; an alkyl group having a substituent such as a benzyl group; a methoxy group, an ethoxy group, and a tertiary group. Examples thereof include an alkoxy group such as a butoxy group. Among these, from the viewpoint of versatility of raw materials and ease of production, the arylene group preferably has 3 or less aromatic rings, more preferably a phenylene group or a naphthylene group, and particularly preferably a phenylene group. As the substituent that may have, similarly, from the viewpoint of versatility of raw materials and ease of production, an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, and an isopropyl group is preferable, and more preferably carbon. A C 1-3 alkyl group, particularly preferably a methyl group.

Ar ⁷ and Ar ⁸ represent an aryl group which may have a substituent, and examples of the aryl group include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a fluorenyl group. Examples of the substituent that the aryl group may have include an alkyl group such as a methyl group, an ethyl group, a propyl group, and an isopropyl group; an alkyl group having a substituent such as a benzyl group; a methoxy group, an ethoxy group, and a tertiary group. Examples thereof include an alkoxy group such as a butoxy group. Among these, considering the influence on the characteristics of the electrophotographic photosensitive member and the production cost, the aryl group preferably has 3 or less aromatic rings, more preferably a phenyl group or a naphthyl group, and particularly preferably a phenyl group. It is a group. Similarly, considering the influence on the characteristics of the electrophotographic photoreceptor and the ease of production, the substituent that may have is preferably an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, or an isopropyl group. More preferably an alkyl group having 1 to 3 carbon atoms, and particularly preferably a methyl group.

Ar ⁷ and Ar ⁸ may be directly bonded to form a ring structure such as carbazole, or may be bonded via a bridging atom such as a nitrogen atom, oxygen atom or sulfur atom to form a ring such as phenothiazine, phenoxazine or xanthene. A structure may be formed or bonded to each other through a divalent organic residue to form a ring structure.
Specific examples of the structure of the azo compound of the present invention are illustrated below, but these exemplifications are representative examples of the azo compound of the present invention, and the azo compound of the present invention is within the spirit of the present invention. Unless it is contrary, it is not limited to the following structures.

<Method for producing azo compound of the present invention>
The azo compound in this invention can be manufactured using a well-known method. The specific example of the manufacturing method of the azo compound in this invention is given to the following. For example, N, N-dimethylformamide and phosphorus oxychloride are allowed to act on a compound having an azobenzene skeleton to formylate, and then a condensation reaction with a hydrazine compound can be performed to obtain the target azo compound.

It is also a target compound by producing a diazonium salt of an aromatic aldehyde compound having an amino group, subjecting the salt and the aromatic compound having an amino group to a diazo coupling reaction, and then performing a condensation reaction with a hydrazine compound. An azo compound can be obtained.
<Electrophotographic photoreceptor>
The photosensitive layer of the electrophotographic photosensitive member is provided on the conductive support, and when it has an undercoat layer, it is provided on the undercoat layer. As the type of the photosensitive layer, the charge generation material and the charge transport material are present in the same layer and are dispersed in a binder resin, a so-called single-layer type photoreceptor, and charge generation in which the charge generation material is dispersed in a binder resin. A so-called laminated type photoreceptor having a multilayer structure in which a layer and a charge transport material are separated into two functions of a charge transport layer in which a binder resin is dispersed in a binder resin can be mentioned, but any structure may be used. Further, an overcoat layer may be provided on the photosensitive layer for the purpose of improving the chargeability and improving the wear resistance.

As the laminated type photosensitive layer, a charge generation layer and a charge transport layer are laminated in this order from the conductive support side, and a reverse lamination layer in which a charge transport layer and a charge generation layer are laminated in reverse order. Any one of them can be used, but a sequentially laminated photosensitive layer that can exhibit the most balanced photoconductivity is preferable.
The azo compound represented by the formula (1) or (2) used in the electrophotographic photosensitive member of the present invention may be contained in any layer formed on the conductive support. Considering that the durability performance against exposure to light, oxidizing gas, and the like from the outside is taken into consideration, the outer layer preferably contains. In the case of a photoreceptor further having an overcoat layer on the photosensitive layer, the inclusion in the overcoat layer also prevents the lower layer from being affected by light of a specific wavelength or oxidizing gas, and is resistant to light and acid. The overcoat layer formed on the photosensitive layer may contain the azo compound of the present invention because it is considered that a high effect on the exposure to the oxidizing gas is obtained. Furthermore, the azo compound of the present invention absorbs a specific wavelength of light at the time of light exposure and suppresses interaction between the binder resin and the charge transport material in an excited state, thereby increasing the residual potential at the time of light exposure. Therefore, it is contained in either the layer containing the binder resin and the charge transporting material, that is, the photosensitive layer of the single-layer type photosensitive member or the charge transporting layer of the multilayer type photosensitive member. More preferably. In particular, since it is highly effective in preventing large fluctuations in the residual potential upon exposure to light, it is preferably contained in the charge transport layer of the sequential lamination type photosensitive layer.

The amount of the azo compound contained is not particularly limited, but it is usually included in the entire layer formed on the conductive support because there is no significant difference in the effect even if it is contained in excess of a certain amount. It is used in an amount of 30 parts by weight or less based on 100 parts by weight of a binder resin described later, and is more preferably 10 parts by weight or less because the abrasion resistance of the photosensitive layer is lowered. Further, if the amount is too small, the effect of the strong exposure resistance of the present invention is lowered, so it is usually used at 0.1 parts by weight or more, preferably 0.3 parts by weight or more, more preferably 0.5 parts by weight or more. Used.
<Conductive support>
As the conductive support used for the photoreceptor, for example, metal materials such as aluminum, aluminum alloy, stainless steel, copper, and nickel, and conductive powders such as metal, carbon, and tin oxide are added to impart conductivity. A resin material, a resin, glass, paper, or the like on which a conductive material such as aluminum, nickel, or ITO (indium tin oxide) is deposited or applied on the surface is mainly used. As a form, a drum shape, a sheet shape, a belt shape, or the like is used. For conductive support of metallic materials, for control of conductivity and surface properties, and for defect coating. A conductive material having an appropriate resistance value may be applied.

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

It is preferable to perform a sealing treatment on the anodic oxide film thus formed. The sealing treatment may be performed by a known method. For example, it is immersed in an aqueous solution containing nickel fluoride as a main component, or immersed in an aqueous solution containing nickel acetate as a main component. A high temperature sealing treatment is preferably performed.
The concentration of the nickel fluoride aqueous solution used in the case of the low-temperature sealing treatment can be appropriately selected, but more preferable results can be obtained when it is used in the range of 3 to 6 g / l. Moreover, in order to advance sealing treatment smoothly, as processing temperature, it is 25-40 degreeC, Preferably it is 30-35 degreeC, Moreover, pH of nickel fluoride aqueous solution is 4.5-6.5, Preferably It is good to process in the range of 5.5-6.0. As the pH adjuster, oxalic acid, boric acid, formic acid, acetic acid, sodium hydroxide, sodium acetate, aqueous ammonia and the like can be used. The treatment time is preferably in the range of 1 to 3 minutes per 1 μm of film thickness. In order to further improve the film properties, cobalt fluoride, cobalt acetate, nickel sulfate, a surfactant and the like may be added to the nickel fluoride aqueous solution. Subsequently, it is washed with water and dried to finish the low temperature sealing treatment. As the sealing agent in the case of the high-temperature sealing treatment, an aqueous metal salt solution such as nickel acetate, cobalt acetate, lead acetate, nickel acetate-cobalt, barium nitrate can be used, and it is particularly preferable to use nickel acetate. . The concentration in the case of using an aqueous nickel acetate solution is preferably 5 to 20 g / l. The treatment temperature is 80 to 100 ° C., preferably 90 to 98 ° C., and the pH of the nickel acetate aqueous solution is preferably 5.0 to 6.0. Here, ammonia water, sodium acetate, or the like can be used as the pH adjuster. The treatment time is 10 minutes or longer, preferably 20 minutes or longer. In this case, sodium acetate, organic carboxylic acid, anionic or nonionic surfactant may be added to the nickel acetate aqueous solution in order to improve the film properties. Subsequently, it is washed with water and dried to finish the high temperature sealing treatment. When the average film thickness is thick, stronger sealing conditions are required due to the higher concentration of the sealing liquid and high temperature / long-time treatment. Accordingly, productivity is deteriorated and surface defects such as spots, dirt, and dusting are likely to occur on the coating surface. From such a point, it is preferable that the average film thickness of the anodic oxide coating is usually 20 μm or less, particularly 7 μm or less.

The support surface may be smooth, or may be roughened by using a special cutting method or polishing. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the support. In order to reduce the cost, the drawing tube can be used as it is without cutting. Especially when using a non-cutting aluminum support such as drawing, impact, and ironing, the treatment eliminates dirt, foreign matter, and other flaws, small scratches, etc. on the surface and provides a uniform and clean support. Therefore, it is preferable.
<Underlayer>
An undercoat layer may be provided between the conductive support and the photosensitive layer described later for improving adhesion and blocking properties. As the undercoat layer, a resin, a resin in which particles such as a metal oxide are dispersed, or the like is used.

  Examples of metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. One kind of these particles may be used alone, or a plurality of kinds of particles may be mixed and used. Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicon. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. Moreover, the thing of the several crystal state may be contained.

Various metal oxide particle diameters can be used. Among them, the average primary particle diameter is usually 1 nm or more, preferably 10 nm, from the viewpoint of electrical characteristics and the stability of the coating liquid for forming the undercoat layer. As described above, it is usually 100 nm or less, preferably 50 nm or less.
The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. As binder resin used for the undercoat layer, epoxy resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, polyurethane resin, Polyimide resin, vinylidene chloride resin, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol resin, polyurethane resin, polyacrylic acid resin, polyacrylamide resin, polyvinyl pyrrolidone resin, polyvinyl pyridine resin, water-soluble polyester resin, nitro Cellulose ester resins such as cellulose, cellulose ether resins, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, zirconium chelation Things, organic zirconium compounds such as zirconium alkoxide compounds, titanyl chelate compounds, organic titanyl compounds such as titanyl alkoxide compound, a known binder resin such as a silane coupling agent and the like. These may be used alone or in combination of two or more in any combination and ratio. Moreover, you may use with the hardening | curing form with the hardening | curing agent. Among these, alcohol-soluble copolymerized polyamides, modified polyamides, and the like are preferable because they exhibit good dispersibility and coatability.

The ratio of the inorganic particles to the binder resin used in the undercoat layer can be arbitrarily selected, but is usually in the range of 10% by weight or more and 500% by weight or less from the viewpoint of dispersion stability and coating properties. Is preferably used.
The thickness of the undercoat layer can be selected arbitrarily, but is usually preferably in the range of 0.1 μm or more and 20 μm or less from the viewpoint of improving the photoreceptor characteristics and applicability.

A known antioxidant or the like may be mixed in the undercoat layer. For the purpose of preventing image defects, pigment particles, resin particles and the like may be contained and used.
<Charge generating material>
Examples of the charge generation material used in the photosensitive layer include selenium and its alloys, amorphous silicon and other inorganic photoconductive materials, phthalocyanine pigments, azo pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments. Various photoconductive materials such as organic pigments such as benzimidazole pigments and squalium pigments can be used, and it is particularly preferable to use organic pigments, especially phthalocyanine pigments and azo pigments. When using phthalocyanine pigments, specifically, metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, aluminum and other metals or oxides, halides, hydroxides, alkoxides thereof And the like, and phthalocyanine dimers using an oxygen atom or the like as a bridging atom.

  In particular, X-type and τ-type metal-free phthalocyanines which are highly sensitive crystal types, A-type (also known as β-type) titanyl phthalocyanine described in JP-A-62-267094, JP-A-5-098174, and the like, B type (also known as α-type) titanyl phthalocyanine described in JP-A-61-217050, JP-A-1-207755, JP-A-4-323270, JP-A-6-287189, etc., JP-A 64-17066 No. 1, JP-A-1-120564, JP-A-2-008256, JP-A-2-28265, JP-A-2-289658, JP-A-3-128973, JP-A-3-269644. , Titanyl phthalocyanines such as D-type (also called Y-type) described in JP-A-8-209023 and JP-A-2003-313457 (Alternative name: oxytitanium phthalocyanine), vanadyl phthalocyanine, chloroindium phthalocyanine, hydroxyindium phthalocyanine, type II chlorogallium phthalocyanine described in JP-A-5-98181, JP-A-5-263007, JP-A-6-279698 V-type hydroxygallium phthalocyanine described in JP-A-10-67946, JP-A-2002-2335014, etc., G described in JP-A-10-88023, JP-A 2000-219817, etc. Μ-oxo-gallium phthalocyanine dimer such as type I and type I and μ-oxo-aluminum phthalocyanine dimer such as type II are preferred.

  Among these phthalocyanines, A type (also known as β type), B type (also known as α type), and X-ray powder diffraction angle 2θ (± 0.2 °) are clearly 27.1 ° or 27.3 °. D-type (Y-type) titanyl phthalocyanine, II-type chlorogallium phthalocyanine, V-type and 28.1 ° having the strongest peak, and 26.2 ° having no peak Hydroxygallium phthalocyanine, G-type μ-oxo-gallium, characterized by having a clear peak at 1 ° and a half width W at 25.9 ° of 0.1 ° ≦ W ≦ 0.4 ° A phthalocyanine dimer and the like are particularly preferable.

  As the phthalocyanine compound, only a single compound may be used, or several mixed or mixed crystal states may be used. As the mixed state in the phthalocyanine compound or crystal state here, the respective constituent elements may be mixed and used later, or mixed in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, and crystallization. It may be the one that caused the condition. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known. In order to generate a mixed crystal state, as described in JP-A-10-48859, there is a method in which two kinds of crystals are mixed and then ground and made amorphous, and then converted into a specific crystal state by solvent treatment. can give. Examples of the phthalocyanine composition used include JP-A-1-221461, JP-A-2-84661, JP-A-3-9962, JP-A-4-97159, JP-A-4-351673, and JP-A-4. JP-A-372663, JP-A-5-2278, JP-A-5-45914, JP-A-5-186702, JP-A-6-145550, JP-A-6-175382, JP-A-6-234937. JP, JP-A-6-271786, JP-A-8-41373, JP-A-8-110649, JP-A-8-176458, JP-A-8-295817, JP-A-9-295817. JP-A 10-48859, JP-A 2000-313819, JP-A 2000-336283, JP 20 The phthalocyanine composition described in JP-A-1-188370, JP-A-2002-129058, JP-A-2002-196519, JP-A-2002-244320, JP-A-2003-43715, and JP-A-2004-4684 Things are preferred.

Preferable examples of the azo pigment include azo pigments described in JP-A Nos. 63-259572, 57-195567, and 5-32905.
These phthalocyanine compounds and azo pigments may be used alone or as a mixture of a plurality of phthalocyanine compounds, a mixed crystal, a mixture of a plurality of azo pigments, or a mixture of a phthalocyanine compound and an azo pigment.
<Charge transport material>
The charge transport material is not particularly limited as long as it is a known material. For example, aromatic nitro compounds such as 2,4,7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, diphenoquinone, etc. Electron withdrawing substances such as quinone compounds, carbazole derivatives, indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, thiadiazole derivatives, heterocyclic compounds such as benzofuran derivatives, aniline derivatives, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives, Examples thereof include butadiene derivatives, enamine derivatives and those obtained by bonding a plurality of these compounds, or electron donating substances such as polymers having groups composed of these compounds in the main chain or side chain. Among these, carbazole derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives, and those in which a plurality of these compounds are bonded are preferable. These substances can be used alone or in combination of two or more.

  Specific examples of suitable structures of the charge transport material are shown below. These specific examples are shown for illustration, and any known charge transporting material may be used as long as it does not contradict the gist of the present invention.

<Binder resin>
The photosensitive layer may be a vapor-deposited film, but is usually formed by binding raw materials such as the charge generation material and the charge transport material with a binder resin. As the binder resin, any binder resin can be used as long as it is usually applicable to an electrophotographic photosensitive member. For example, polyvinyl acetate, polyacrylate ester, Methacrylic acid ester, polyester, polycarbonate, polyvinyl acetoacetal, polyvinyl propional, polyvinyl butyral, phenoxy resin, epoxy resin, urethane resin, cellulose ester, cellulose ether, polyvinyl chloride copolymer, polyvinyl acetate copolymer, etc. A binder resin is used. In this case, the usage ratio of the binder resin and the charge generation material is used in the range of 30 to 500 parts by weight of the charge generation material with respect to 100 parts by weight of the binder resin, and the film thickness of the charge generation layer is usually 0.1 μm to 2 μm. The thickness is preferably 0.15 μm to 1 μm.

  Examples of the binder resin used in the charge transport layer of the multilayer photoreceptor and the photosensitive layer of the single-layer photoreceptor include, for example, butadiene resin, styrene resin, vinyl acetate resin, vinyl chloride resin, acrylic ester resin, and methacrylic ester. Polymers and copolymers of vinyl compounds such as resins, vinyl alcohol resins, ethyl vinyl ether, polyvinyl butyral resins, polyvinyl formal resins, partially modified polyvinyl acetals, polycarbonate resins, polyester resins, polyarylate resins, polyamide resins, polyurethane resins, cellulose Examples thereof include an ester resin, a phenoxy resin, a silicon resin, a silicon-alkyd resin, and a poly-N-vinylcarbazole resin. Of the binder resins, polycarbonate resin, polyarylate resin or polyester polycarbonate resin is preferable, polyarylate resin or polycarbonate resin is more preferably used, and polyarylate resin is particularly used. These can also be used by crosslinking with an appropriate curing agent by heat, light or the like. Two or more kinds of binder resins can be blended and used.

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

  In the case of a single-layer type photoreceptor, the charge generating substance is further dispersed in the charge transport medium having the above-described blending ratio. In this case, the particle size of the charge generating material needs to be sufficiently small, preferably 1 μm or less, more preferably 0.5 μm or less. If the amount of the charge generating material dispersed in the photosensitive layer is too small, sufficient sensitivity cannot be obtained. If the amount is too large, there is an adverse effect of reduced chargeability and reduced sensitivity, for example, preferably 0.1 to 50% by weight. It is used in the range, preferably in the range of 1 to 20% by weight.

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

A protective layer may be provided on the outermost surface layer of the photosensitive member for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to a discharge substance generated from a charger or the like. The protective layer is formed by containing a conductive material in an appropriate binder resin, or charge transporting ability such as a triphenylamine skeleton as described in JP-A-9-190004 and JP-A-10-252377. The copolymer using the compound which has can be used. Examples of the conductive material include aromatic amino compounds such as TPD (N, N′-diphenyl-N, N′-bis- (m-tolyl) benzidine), antimony oxide, indium oxide, tin oxide, titanium oxide, and tin oxide. -Metal oxides such as antimony oxide, aluminum oxide, and zinc oxide can be used, but are not limited thereto. As the binder resin used for the protective layer, known resins such as polyamide resin, polyurethane resin, polyester resin, epoxy resin, polyketone resin, polycarbonate resin, polyvinyl ketone resin, polystyrene resin, polyacrylamide resin, and siloxane resin can be used. Further, a copolymer of the above resin with a skeleton having a charge transporting ability such as a triphenylamine skeleton as described in JP-A-9-190004 and JP-A-10-252377 can also be used. The protective layer is preferably configured to have an electric resistance of 10 ⁹ to 10 ¹⁴ Ω · cm. When the electrical resistance is higher than 10 ¹⁴ Ω · cm, the residual potential is increased, resulting in an image with much fog. On the other hand, when the electric resistance is lower than 10 ⁹ Ω · cm, the image is blurred and the resolution is lowered. In addition, the protective layer must be configured so as not to substantially impede transmission of light irradiated for image exposure.

In addition, fluorine resin, silicone resin, polyethylene resin, polystyrene resin, etc. are used for the surface layer for the purpose of reducing frictional resistance and abrasion on the surface of the photoconductor and increasing the transfer efficiency of the toner from the photoconductor to the transfer belt and paper. May be included. Moreover, the particle | grains which consist of these resin, and the particle | grains of an inorganic compound may be included.
<Layer formation method>
Each layer constituting the photoreceptor is formed by sequentially applying a coating solution containing the material constituting each layer on the support using a known coating method and repeating the coating and drying process for each layer. The

The coating solution for forming a layer is used in the case of a charge transport layer of a single layer type photoreceptor or a multilayer type photoreceptor, and the solid content is usually used in the range of 5 to 40% by weight, but 10 to 35% by weight. It is preferable to use in the range. The viscosity of the coating solution is usually used in the range of 10 to 500 cps, but preferably in the range of 50 to 400 cps.
In the case of the charge generating layer of the multilayer photoreceptor, the solid content is usually used in the range of 0.1 to 15% by weight, but more preferably in the range of 1 to 10% by weight. The viscosity of the coating solution is usually used in the range of 0.01 to 20 cps, but more preferably in the range of 0.1 to 10 cps.

Examples of the application method of the coating liquid include dip coating, spray coating, spinner coating, bead coating, wire bar coating, blade coating, roller coating, air knife coating, and curtain coating. Other known coating methods can also be used.
The coating solution is preferably dried by touching at room temperature and then heating and drying in a temperature range of 30 to 200 ° C. for 1 minute to 2 hours with no air or air. The heating temperature may be constant or may be changed while drying.
<Image forming apparatus>
Next, an embodiment of an image forming apparatus using the electrophotographic photosensitive member of the present invention (an image forming apparatus of the present invention) will be described with reference to FIG. However, the embodiment is not limited to the following description, and can be arbitrarily modified without departing from the gist of the present invention.

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

  The charging device 2 charges the electrophotographic photosensitive member 1 and uniformly charges the surface of the electrophotographic photosensitive member 1 to a predetermined potential. As the charging device, a corona charging device such as corotron or scorotron, a direct charging device (contact type charging device) in which a direct charging member to which voltage is applied is brought into contact with the surface of the photosensitive member and charged is often used. Examples of direct charging means include contact chargers such as charging rollers and charging brushes. In FIG. 1, a roller-type charging device (charging roller) is shown as an example of the charging device 2. As the direct charging means, either charging with air discharge or injection charging without air discharge is possible. It is also possible to adopt an NC roller charging method in which charging is performed in a state where a photosensitive sheet and a charging roller are kept in non-contact at a stable charging distance by winding a resin sheet or the like around the charging roller. Moreover, as a voltage applied at the time of charging, it is possible to use only a direct current voltage or to superimpose alternating current on direct current.

  The type of the exposure apparatus 3 is not particularly limited as long as it can expose the electrophotographic photoreceptor 1 to form an electrostatic latent image on the photosensitive surface of the electrophotographic photoreceptor 1. Specific examples include halogen lamps, fluorescent lamps, lasers such as semiconductor lasers and He—Ne lasers, LEDs, and the like. Further, exposure may be performed by a photoreceptor internal exposure method. As the digital electrophotographic system, it is preferable to use a laser, an LED, an optical shutter array, or the like. The light used for the exposure is arbitrary. For example, the exposure may be performed using monochromatic light with a wavelength of 780 nm, monochromatic light with a wavelength slightly shorter than 600 nm to 700 nm, or monochromatic light with a short wavelength of 380 nm to 500 nm. .

  The type of the developing device 4 is not particularly limited, and an arbitrary device such as a dry development method such as cascade development, one-component insulating toner development, one-component conductive toner development, or two-component magnetic brush development, or a wet development method is used. be able to. In FIG. 1, the developing device 4 includes a developing tank 41, an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45, and has a configuration in which toner T is stored inside the developing tank 41. . Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing device 4 as necessary. The replenishing device is configured to be able to replenish toner T from a container such as a bottle or a cartridge. The development method may be either a contact method or a non-contact method. As the toner to be used, in addition to the pulverized toner, chemical toners such as suspension granulation, suspension polymerization, and emulsion polymerization aggregation method can be used. In particular, in the case of chemical toners, those having a small particle size of about 4 to 8 μm are used, and those having a shape close to a sphere, and those outside the potato and rugby ball shape can also be used. The polymerized toner is excellent in charging uniformity and transferability and is suitably used for high image quality.

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

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

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

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

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

When the toner transferred onto the recording paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated to a molten state and cooled after passing through the recording paper. Toner is fixed on P.
There is no particular limitation on the type of the fixing device, and fixing by any method such as the one used here, heat roller fixing, flash fixing, oven fixing, pressure fixing, IH fixing, belt fixing, IHF fixing, etc. A device can be provided. Any of these known methods can be used, and these fixing methods may be used singly or in combination of a plurality of fixing methods.

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

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

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

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

Hereinafter, the present invention will be described by way of examples. The examples are given for the purpose of illustrating the present invention in detail, and are not limited to the examples unless they are contrary to the gist of the present invention. In Examples, Comparative Examples and Application Examples, the part means “part by weight”.
<Synthesis Example 1>
9.1 parts of 4-aminobenzaldehyde is diazotized in concentrated hydrochloric acid by a known method, and the reaction is represented by the following formula by coupling reaction with 8.2 parts of N, N-diethyl-m-toluidine and 100 parts of methanol. 10.6 parts of compound were obtained.

  8.9 parts of the above compound, 8.3 parts of N, N-diphenylhydrazine, 30 parts of methanol, and 30 parts of tetrahydrofuran were mixed and stirred at 60 ° C. for 2 hours in a nitrogen atmosphere. After standing to cool, the precipitated red crystals were taken out by filtration and then purified by known column chromatography to obtain 9.3 parts of azo compound A having the following structural formula as the target substance. The infrared absorption spectrum of the compound is shown in FIG.

<Synthesis Example 2>
In Synthesis Example 1, 8.2 parts of N, N-diethyl-m-toluidine was changed to 11.0 parts of N, N-di-n-propyl-m-toluidine, and 8.3 parts of N, N-diphenylhydrazine was used. Was changed to 9.6 parts of N, N-di-p-tolylhydrazine, and 9.7 parts of azo substance B having the following structural formula as the target substance was obtained by performing the same operation as in Synthesis Example 1. Obtained.

<Synthesis Example 3>
By performing the same operation as in Synthesis Example 1 except that 8.3 parts of N, N-diphenylhydrazine in Synthesis Example 1 was changed to 10.6 parts of N-phenyl-N- (1-naphthyl) hydrazine, As a material, 9.5 parts of azo compound C having the following structural formula was obtained.

<Comparative Synthesis Example 1>
By performing the same operation as in Synthesis Example 1 except that 8.2 parts of N, N-diethyl-m-toluidine in Synthesis Example 1 was changed to 7.5 parts of N, N-diethylaniline, JP-A-3- 8.9 parts of compound D having the following structural formula described in Example 3 in Japanese Patent No. 55558 were obtained. The infrared absorption spectrum of the compound is shown in FIG.

<Comparative Synthesis Example 2>
The same operation as in Synthesis Example 1 is performed except that 8.2 parts of N, N-diethyl-m-toluidine in Synthesis Example 1 is changed to 11.0 parts of N, N-di-n-butyl-m-toluidine. As a result, 9.5 parts of Compound E having the following structural formula described in Production Examples in JP-A-3-55558 was obtained.

<Comparative Synthesis Example 3>
By performing the same operation as in Synthesis Example 3, except that 8.2 parts of N, N-diethyl-m-toluidine in Synthesis Example 3 was changed to 9.6 parts of N, Nn-dipropyl-m-toluidine. 9.1 parts of compound F having the following structural formula described in Example 5 of JP-A-3-55558 was obtained.

<Example 1>
(Preparation of electrophotographic photoreceptor)
The undercoat layer dispersion was produced as follows. That is, a rutile type titanium oxide having an average primary particle size of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by weight of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) with respect to the titanium oxide were flowed at high speed. In a mixed solvent of methanol / 1-propanol in a mixed solvent of methanol / 1-propanol, which was put into a high-pressure mixing kneader (“SMG300” manufactured by Kawata Co., Ltd.) Then, a dispersion slurry of hydrophobized titanium oxide was obtained by dispersing with a ball mill. The dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam [compound represented by the following formula (A)] / bis (4-amino-3-methylcyclohexyl) methane [the following formula (B Compound represented by the following formula (C)] / decamethylene dicarboxylic acid [compound represented by the following formula (D)] / octadecamethylene dicarboxylic acid [in the following formula (E) The compositional molar ratio of the compound represented] is 75% / 9.5% / 3% / 9.5% / 3% of the copolymerized polyamide pellets with heating and stirring and mixing to dissolve the polyamide pellets. After that, by carrying out ultrasonic dispersion treatment, the weight ratio of methanol / 1-propanol / toluene is 7/1/2, and hydrophobically treated titanium oxide. The copolymerized polyamide in a weight ratio of 3/1, and a solid concentration of 18.0% of the undercoat layer dispersion.

Using a conductive support in which an aluminum vapor deposition layer (thickness 70 nm) is formed on the surface of a biaxially stretched polyethylene terephthalate resin film (thickness 75 μm), the above dispersion for the undercoat layer is placed on the vapor deposition layer of the support. The coater was applied so that the film thickness after drying was 1.25 μm and dried to form an undercoat layer.
As a charge generation material, 20 parts by weight of titanium oxyphthalocyanine having a powder X-ray diffraction spectrum pattern with respect to CuKα characteristic X-ray shown in FIG. 4 and 280 parts by weight of 1,2-dimethoxyethane are mixed and pulverized with a sand grind mill for 2 hours. Then, the atomization dispersion treatment was performed. Subsequently, polyvinyl butyral (trade name “Denkabutyral” # 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.) was added to 253 parts by weight of 1,2-dimethoxyethane and 4-methoxy-4-methyl-2. A dispersion was prepared by mixing a binder liquid obtained by dissolving pentanone in 85 parts by weight of a mixed liquid and 234 parts by weight of 1,2-dimethoxyethane. This dispersion was applied onto the undercoat layer with a bar coater to form a charge generation layer so that the film thickness after drying was 0.4 μm.

  50 parts of the aromatic amine derivative composition (A) described in Example 1 of JP-A No. 2002-275135 mainly composed of the following structure as a charge transporting substance, the azo compound A obtained in Synthesis Example 1 5 parts by weight, 100 parts by weight of the binder resin (A) shown below as the binder resin, and 0.05 parts by weight of silicone oil as the leveling agent, 640 parts by weight of a mixed solvent of tetrahydrofuran / toluene (weight ratio 8/2) To obtain a charge transport layer coating solution. The coating solution is applied onto the charge generation layer with a film applicator so that the film thickness after drying is 25 μm, and dried to form a charge transport layer, thereby forming an electrophotographic photosensitive layer having a laminated photosensitive layer. The body was made.

Example 2
An electrophotographic photoreceptor having a multilayer photosensitive layer was produced by performing the same operation as in Example 1 except that the azo compound A in Example 1 was changed to the azo compound B obtained in Synthesis Example 2.
Example 3
An electrophotographic photoreceptor having a multilayer photosensitive layer was prepared by performing the same operation as in Example 1 except that the azo compound A in Example 1 was changed to the azo compound C obtained in Synthesis Example 3.
Comparative Example 1
An electrophotographic photosensitive member having a laminated photosensitive layer was produced by performing the same operation as in Example 1 except that the azo compound A in Example 1 was not used.
Comparative Example 2
An electrophotographic photoreceptor having a multilayer photosensitive layer was produced by performing the same operation as in Example 1 except that the azo compound A in Example 1 was changed to the azo compound D obtained in Comparative Synthesis Example 1. .
Comparative Example 3
An electrophotographic photosensitive member having a multilayer photosensitive layer was produced by performing the same operation as in Example 1 except that the azo compound A in Example 1 was changed to the azo compound E obtained in Comparative Synthesis Example 2. .
Comparative Example 4
An electrophotographic photosensitive member having a multilayer photosensitive layer was produced by performing the same operation as in Example 1 except that the azo compound A in Example 1 was changed to the azo compound F obtained in Comparative Synthesis Example 3. .

(Evaluation of electrical characteristics)
An electrophotographic characteristic evaluation apparatus prepared according to the standard of the Electrophotographic Society using the electrophotographic photoreceptor obtained in Example 1-3 and Comparative Example 1-4 (basic and applied electrophotographic techniques, edited by the Electrophotographic Society, Corona And the electrical characteristics were evaluated by the charging, exposure, potential measurement, and charge removal cycles according to the following procedures.

Irradiation energy (half-exposure exposure) when the surface potential becomes -350 V by charging the photosensitive member so that the initial surface potential is -700 V and irradiating the light of the halogen lamp with a monochromatic light of 780 nm with an interference filter. Energy) was measured as sensitivity (E1 / 2) (μJ / cm ² ). Further, the post-exposure surface potential (Vl) after 100 milliseconds when the exposure light was irradiated at an intensity of 1.2 μJ / cm ² was measured. Further, after the initial surface potential was set to −700 V, the surface potential after being left in a dark place for 5 seconds was measured, and the difference was defined as dark decay (DD).

  Table 1 shows the evaluation results of electrophotographic characteristics of each of the photoreceptors manufactured in Examples 1 to 3 and Comparative Examples 1 to 4.

  From the results of Table 1, the electrophotographic photosensitive member containing the azo compound of the present invention of Examples 1 to 3 has a value of DD and Vl as compared with the electrophotographic photosensitive member of Comparative Example 1 not containing the azo compound. Since there is almost no difference, there is almost no change in the electrical characteristics and no adverse effect on the electrical characteristics of the photoreceptor is observed, but in the electrophotographic photoreceptors of Comparative Examples 2 to 4, increases in DD and Vl were confirmed, and electrophotography It can be seen that the electrical characteristics of the photoreceptor are adversely affected.

Next, light from a white fluorescent lamp (“Neormi Super FL20SS · W / 18” manufactured by Mitsubishi OSRAM) is applied to the photoreceptors obtained in Examples 1 to 3 and Comparative Examples 1 to 4 on the photoreceptor surface. After adjusting the light intensity to 2000 lux and irradiating for 10 minutes, the same operation as the evaluation of the electrophotographic photoreceptor characteristics was performed, and the initial surface potential (V ′) after light exposure and after light exposure The surface potential after exposure (Vl ′) is measured, and the amount of change in the initial surface potential (VV ′) before and after light exposure and the amount of change in surface potential after light exposure (Vl−Vl ′) are calculated. To evaluate the light resistance,
The results are shown in Table 2.

From the results in Table 2, the electrophotographic photoreceptors of Examples 1 to 3 containing the azo compound of the present invention are the electrophotographic photoreceptors not containing the azo compound of Comparative Example 1 and the prior arts of Comparative Examples 2 to 4. It can be seen that, compared with the electrophotographic photoreceptor containing the azo compound, the potential fluctuation at the time of light exposure is suppressed to be particularly small.
Example 4
An aluminum non-cutting tube (an outer diameter of 30 mm, a length of 340 mm, and a wall thickness of 0.8 mm) whose surface was anodized and sealed was prepared in the same manner as in Example 1 and applied for a charge generation layer. Immerse in the solution, apply so that the film thickness after drying is 0.4 μm, and dry to form a charge generation layer. Subsequently, for the charge transport layer prepared in the same manner as in Example 1 An electrophotographic photosensitive drum having a laminated photosensitive layer was prepared by immersing in a coating solution, coating the film so that the film thickness after drying was 25.5 μm, and drying to form a charge transport layer.

On the obtained electrophotographic photosensitive drum, in order to create a portion exposed by light of a white fluorescent lamp and a portion not exposed, the entire surface of the photosensitive member is covered with black paper having a hole of 20 mm in length and 40 mm in width, From there, adjust the light of the white fluorescent lamp (“Neormi Super FL20SS / W / 18” manufactured by Mitsubishi OSRAM) so that the light intensity on the surface of the photoreceptor is 2000 lux, and make a hole in the black paper After irradiating the open area for 10 minutes, the black paper is removed, and the drum is mounted on a drum cartridge for black image formation of a tandem color printer ("SPEDIA N5" manufactured by Casio). When a solid image was printed out and an image formation evaluation test was performed, there was no image defect such as a change in image density due to the influence of exposure by a white fluorescent lamp, and there was no noise. A good image was obtained.
Comparative Example 5
An electrophotographic photosensitive drum having a laminated photosensitive layer was prepared by the same operation as in Example 4 except that no azo compound was used in the charge transport layer, and evaluated in the same manner. Due to the influence of exposure, a black belt with a length of 20 mm and a width of 40 mm was clearly confirmed in the drum cycle, and an increase in the image density of the light-exposed portion was observed, and a good image was not obtained.
Comparative Example 6
Except that the azo compound obtained in Comparative Synthesis Example 2 was used for the charge transport layer, an electrophotographic photosensitive drum having a laminated photosensitive layer was prepared by performing the same operation as in Example 4, and the same evaluation was performed. As a result, a black belt having a length of 20 mm and a width of 40 mm was confirmed in the drum cycle due to the influence of the exposure by the white fluorescent lamp, and an increase in the image density of the light-exposed portion was observed, and a good image was not obtained.

1 is a schematic diagram illustrating a main configuration of an embodiment of an image forming apparatus of the present invention. It is an infrared absorption spectrum of the azo compound A obtained in Synthesis Example 1 of the present invention. 3 is an infrared absorption spectrum of azo compound D obtained in Comparative Synthesis Example 1 of the present invention. It is a powder X-ray diffraction pattern of the phthalocyanine compound used in Example 1 of the present invention.

Claims (5)

In the electrophotographic photosensitive member having a photosensitive layer on a conductive support, any layer formed on the conductive support contains an azo compound represented by the following general formula (1). An electrophotographic photoreceptor.

Wherein R ¹ and R ² are alkyl groups having 3 or less carbon atoms that may have a substituent, Ar ¹ is an arylene group having an alkyl group, and Ar ² is an arylene that may have a substituent. Groups Ar ³ and Ar ⁴ represent a phenyl group which may have an alkyl group as a substituent. In the electrophotographic photosensitive member having a photosensitive layer on a conductive support, any layer formed on the conductive support contains an azo compound represented by the following general formula (2). An electrophotographic photoreceptor.

Wherein R ³ and R ⁴ are alkyl groups having 2 or less carbon atoms, Ar ⁵ is a phenylene group having an alkyl group, Ar ⁶ is an arylene group which may have a substituent, Ar ⁷ and Ar ⁸ are substituents Represents an optionally substituted aryl group.) An electrophotographic cartridge using the electrophotographic photosensitive member according to claim 1. An image forming apparatus using the electrophotographic photosensitive member according to claim 1. An image forming method using the electrophotographic photosensitive member according to claim 1 or 2 or the cartridge according to claim 3.

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