JP2006003885A - Electrophotographic photoreceptor, electrophotographic photoreceptor cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the occurrence of leak and memory in image formation using an image forming apparatus. <P>SOLUTION: There is provided an electrophotographic photoreceptor composed of an anodized and sealed conductive support and a layer which is formed on the conductive support and contains at least one tetraphenylbenzidine derivative having one or more substituents on each phenyl group bonding to the benzidine skeleton. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrophotographic photosensitive member, and an electrophotographic photosensitive member cartridge and an image forming apparatus using the same.

In recent years, electrophotographic technology has been widely used and applied not only in the field of copying machines but also in the fields of various printers and printing presses because of its immediacy and high quality images.
Electrophotographic photoreceptors, which are the core of electrophotographic technology, have been used as conventional photoconductive materials for inorganic photoconductors such as amorphous selenium, arsenic-selenium alloys, cadmium sulfide, and zinc oxide. Therefore, the use of an electrophotographic photoreceptor using an organic photoconductive material having advantages such as easy film formation and easy manufacture has become the mainstream.

  As a layer structure of the organic photoreceptor, a so-called single-layer photoreceptor in which a charge generation material is dispersed in a binder resin, and a laminated photoreceptor in which a charge generation layer and a charge transfer layer are laminated are known. Multilayer photoconductors can provide highly sensitive and stable electrophotographic photoconductors by separating the highly efficient charge generating material and charge transfer material into separate layers and combining them optimally. Widely used because of the wide ease of adjusting the characteristics.

  Single layer type photoconductors are slightly inferior to multilayer photoconductors in terms of electrical characteristics, and material selectivity is narrow, but high resolution can be achieved by generating charges in the vicinity of the photoconductor surface. Since the image is not blurred, high printing durability can be achieved by increasing the film thickness. In addition, the single-layer type photosensitive member requires fewer coating processes, is advantageous for interference fringes and tube defects derived from a conductive substrate (support), and can be used with a low-priced substrate such as a non-cutting tube. It has the advantage of cost reduction.

  In addition, since the electrophotographic photosensitive member is repeatedly used in an electrophotographic process, that is, a cycle of charging, exposure, development, transfer, cleaning, static elimination, and the like, it is deteriorated by various stresses during that time. Among these, chemical deterioration includes, for example, that strong oxidizing ozone or NOx generated from a corona charger that is usually used as a charger gives damage to the photosensitive layer. Deterioration in electrical stability such as a decrease in the residual potential and an increase in residual potential, and accompanying image defects may occur. These are largely derived from chemical deterioration of charge transport materials contained in the photosensitive layer in a large amount.

  Furthermore, with the recent increase in the speed of electrophotographic processes, higher sensitivity and faster response are essential. Of these, in order to achieve high sensitivity, it is necessary not only to optimize charge generation materials, but also to develop charge transport materials with good matching with them. For high-speed response, high mobility and exposure It is sometimes necessary to develop charge transport materials that exhibit a sufficiently low residual potential. Various techniques have been developed so far to solve such technical problems (Patent Documents 1 to 6).

  Further, it is well known that leakage due to discharge often occurs in an electrophotographic photosensitive member because a high electric field is applied in the development process. When a leak occurs during printing, an image defect is caused. Therefore, the use of a conductive support that has been subjected to an anodizing process and a sealing process that are resistant to the leak is increasing (Patent Documents 7 and 8). .

JP-A-3-225345 JP-A-6-214409 JP 2000-56490 A JP-A-4-182655 EP 314195 JP-A-1-118141 Japanese Patent No. 3412301 Japanese Patent No. 2661435

However, with the recent increase in image quality, the occurrence of memory, which is considered to be caused by exposure history, has become prominent. Here, the memory is a phenomenon in which an exposure history remains at the time of the next development at the time of image formation, and the previous image appears overlapping with the image to be formed next time. However, conventional memories such as Patent Documents 1 to 6 cannot solve this memory. In particular, as in Patent Documents 7 and 8, in an electrophotographic photosensitive member using a conductive support that has been subjected to anodizing treatment and sealing treatment to suppress the occurrence of leakage, a positive type memory (exposure of the exposure) is performed. The phenomenon that the history appears as a dark memory image in the next development is remarkable, and its improvement has been demanded.
The present invention has been made in view of the above problems, and provides an electrophotographic photosensitive member capable of suppressing the occurrence of leakage and memory during image formation, and an electrophotographic photosensitive member cartridge and an image forming apparatus using the same. The purpose is to provide.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention, as a result, an electrophotographic apparatus comprising a conductive support subjected to anodizing treatment and sealing treatment, and a layer having a specific charge transporting material. The present inventors have found that the photoreceptor can suppress the occurrence of leakage and memory, and have completed the present invention.

  That is, the gist of the present invention is to provide an electroconductive support subjected to anodizing treatment and sealing treatment, and one or more substituents each on a phenyl group formed on the electroconductive support and bonded to a benzidine skeleton. And a layer containing at least one kind of tetraphenylbenzidine derivative having the above. Here, the term “formed on the conductive support” means not only when it is directly formed on the surface of the conductive support but also when it is formed on the conductive support via any other layer. To include.

（式［１］中、Ａｒ¹、Ａｒ²は、それぞれ独立して、少なくとも１個の置換基を有するフェニル基を表し、Ａｒ³、Ａｒ⁴は、それぞれ独立して、置換基を有しても良いアリーレン基を表し、

及び

は、それぞれ独立して、Ｒａ以外の置換基を有しても良いフェニル基を表し、Ｒａは、それぞれ独立して、対応するフェニル基のメタ位又はパラ位を置換するアルキル基を表す。） In this case, the tetraphenylbenzidine derivative is preferably a compound represented by the following formula [1].

(In the formula [1], Ar ¹ and Ar ² each independently represent a phenyl group having at least one substituent, and Ar ³ and Ar ⁴ each independently have a substituent. Also represents a good arylene group,

as well as

Each independently represents a phenyl group which may have a substituent other than Ra, and each Ra independently represents an alkyl group which substitutes the corresponding meta or para position of the phenyl group. )

（式［２］中、Ｒ¹及びＲ²は、それぞれ独立して、メチル基又はメトキシ基を表し、Ｒ³、Ｒ⁴、Ｒ⁵及びＲ⁶は、それぞれ独立して、水素原子又はメチル基を表す。） Furthermore, it is preferable that this compound is what is represented by following formula [2].

(In the formula [2], R ¹ and R ² each independently represent a methyl group or a methoxy group, and R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group. Represents.)

The electrophotographic photosensitive member preferably has a layer formed on the conductive support and containing oxytitanium phthalocyanine.
Further, the oxytitanium phthalocyanine exhibits a diffraction peak at a Bragg angle (2θ ± 0.2) of 27.3 ° in the X-ray diffraction spectrum, or 9.3 °, 10.6 °, and 26.3. It preferably has a diffraction peak at ° (Claim 5).

  Another gist of the present invention is the above-described electrophotographic photosensitive member, a charging unit that charges the electrophotographic photosensitive member, an exposure unit that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image, and An electrophotographic photosensitive member cartridge is provided with at least one developing unit that develops an electrostatic latent image formed on the electrophotographic photosensitive member.

  Still another gist of the present invention is the above-described electrophotographic photosensitive member, a charging unit that charges the electrophotographic photosensitive member, an exposure unit that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image, and An image forming apparatus comprising: a developing unit that develops an electrostatic latent image formed on the electrophotographic photosensitive member.

  According to the electrophotographic photosensitive member of the present invention, and the electrophotographic photosensitive member cartridge and the image forming apparatus using the same, it is possible to suppress the occurrence of leakage and memory during image formation.

Hereinafter, although embodiment of this invention is described, this invention is not limited to the following embodiment, In the range which does not deviate from the summary of this invention, it can change arbitrarily and can implement.
[I. Electrophotographic photoreceptor]
The electrophotographic photoreceptor of the present invention comprises a conductive support and a layer containing at least one tetraphenylbenzidine derivative.

[1. Tetraphenylbenzidine derivative]
The tetraphenylbenzidine derivative used in the electrophotographic photoreceptor of the present invention (hereinafter referred to as “the tetraphenylbenzidine derivative of the present invention” as appropriate) has one or more substituents each on the phenyl group bonded to the amino group of the benzidine skeleton. It is a derivative of N, N, N ′, N′-tetraphenylbenzidine having a group, and is used as a charge transport material for an electrophotographic photoreceptor. There is no particular limitation on the substituent for substituting the phenyl group of this tetraphenylbenzidine derivative, and any group can be used as the substituent. For example, an alkyl group, an alkoxy group, an aryl group, and a condensed polycyclic group are preferable, A C1-C10 alkyl group is more preferable, a C1-C5 alkyl group is still more preferable, and a methyl group is especially preferable. Further, the number of substituents possessed by the tetraphenylbenzidine derivative is usually 4 or more, preferably 6 or more.

The tetraphenylbenzidine derivative as the charge transport material is usually preferably a compound represented by the following formula [1].

In the above formula [1], Ar ¹ and Ar ² each independently represent a phenyl group having at least one substituent, and Ar ³ and Ar ⁴ each independently have a substituent. Represents a good arylene group. Specific examples of Ar ³ and Ar ⁴ include a phenylene group and a naphthylene group, among which a phenylene group is preferable.

Here, examples of the substituent that Ar ^{1 to} Ar ⁴ may have include an alkyl group such as a methyl group, an ethyl group, and a propyl group, an alkoxy group such as a methoxy group and an ethoxy group, a phenyl group, a naphthyl group, and an anthracenyl group. Aryl groups such as pyrenyl group and perylenyl group, condensed polycyclic groups such as acenaphthenyl group, carbazolyl group, quinolinyl group, benzothienyl group, dibenzothienyl group, indolyl group and tetrahydronaphthyl group. Among these, in view of image characteristics, an alkyl group is preferable, and an alkyl group having 1 to 5 carbon atoms is more preferable, and a methyl group is particularly preferable in consideration of ease of production. However, those having silicon, a carbonyl group, or an ester group as a substituent are not preferable because there is a possibility that the electrical characteristics may be deteriorated under high humidity. Ar ³ and Ar ⁴ may be bonded to each other through a substituent to form a ring. The substituents Ar ¹ and Ar ² may be condensed to form a ring. In that case, Ar ¹ and Ar ² can also be regarded as an aryl group having a condensed ring such as a naphthyl group.

及び

はフェニル基を表わす。 Also,

as well as

Represents a phenyl group.

は、それぞれ独立して、Ｒａ以外の置換基を有しても良い。その置換基としては、Ａｒ¹〜Ａｒ⁴の置換基と同様のものが挙げられるが、画像特性を考えた場合、Ｒａ又は窒素原子に結合した位置以外は無置換である事が好ましい。 further,

Each independently may have a substituent other than Ra. Examples of the substituent include those similar to the substituents of Ar ^{1 to} Ar ⁴ , but in view of image characteristics, it is preferably unsubstituted except for a position bonded to Ra or a nitrogen atom.

のメタ位又はパラ位に置換したアルキル基を表す。また、Ｒａは更に置換基を有していてもよい。Ｒａが有する置換基としては、Ａｒ¹〜Ａｒ⁴の置換基と同様のものが挙げられる。 Further, each Ra is independently a corresponding phenyl group, that is, the Ra is bonded.

Represents an alkyl group substituted at the meta or para position. Ra may further have a substituent. Examples of the substituent Ra have, those similar to the substituents of Ar ¹ to Ar ^4.

In particular, considering image characteristics, the compound represented by the formula [1] is preferably represented by the following formula [2].

In the above formula [2], R ¹ and R ² each independently represent a methyl group or a methoxy group. However, as R ¹ and R ² , a methyl group is preferable in view of improving the mobility, and a methoxy group is preferable for improving the residual potential.

R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group.
R ³ and R ⁴ are preferably hydrogen atoms in terms of electrical characteristics, considering a combination with titanyloxyphthalocyanine used as a charge generating material.
On the other hand, R ⁵ and R ⁶ are preferably methyl groups from the viewpoint of mobility, but in combination with the titanyloxyphthalocyanine D type used as the charge generation material, hydrogen atoms are not present from the viewpoint of electrical characteristics and image characteristics. preferable. When R ⁵ and R ⁶ are methyl groups, R ¹ and R ² are preferably bonded to the m position with respect to the nitrogen atom from the viewpoint of image quality.

  Further, the molecular weight of the above-mentioned tetraphenylbenzidine derivative is usually 2000 or less, preferably 1000 or less in view of repeatability.

  The following are typical examples of tetraphenylbenzidine derivatives used as charge transport materials for the photoreceptor of the present invention. These representative examples are shown for illustration, and the tetraphenylbenzidine derivatives used in the present invention are not limited to these representative examples. In addition, the code | symbol shown on the left of the following structural formula is the number of the exemplary compound attached | subjected for description.

Moreover, there is no restriction | limiting in the manufacturing method of the said tetraphenyl benzidine derivative, It can manufacture by arbitrary methods. Here, as an example of a method for producing a tetraphenylbenzidine derivative, a method for producing a compound represented by the above formula [2] will be described.
As a method for producing the compound represented by the formula [2], (1) a diphenylamine derivative is synthesized and then reacted with a dihalogenated biphenyl, or (2) a diphenylbenzidine derivative is synthesized from a dihalogenated biphenyl and then the formula [2 And the like. The reaction formula of the method (1) is shown below.

In the above reaction formula, PrOH represents propanol and X represents a halogen atom. From the viewpoint of reactivity, preferred as X is an iodine atom, but from the viewpoint of inexpensive production, a bromine atom may be used.
Hereinafter, the method (1) will be described in detail.

  First, a 3,4-xylidine derivative is acetylated with acetic anhydride to prepare an amide derivative. Next, this amide derivative is coupled with bromoalkylbenzene or iodoalkylbenzene, and the acetyl group is further deprotected with potassium hydroxide / propanol to derive a diarylamine form. Finally, it is coupled with dihalogenated biphenyl to construct the final product.

  In addition, each coupling reaction in the said manufacturing method may be performed by the Ullmann (Ullmann) reaction using a copper catalyst or an iron catalyst, and may be performed by the method of using a Pd catalyst. However, it is preferable to use a Pd catalyst from the viewpoint of improving electrical characteristics. In particular, from the viewpoint of reducing the purification load, that is, since the coupling reaction proceeds well, considering that the raw material hardly remains in the product and is easy to purify, the diarylamine compound and dihalogen in the final reaction step are considered. It is preferable to use a Pd catalyst in the coupling reaction with biphenyl fluoride.

  Further, when coupling is performed using a Pd catalyst, it is preferable to forcibly discharge the generated alcohol or the like out of the system at an early stage from the viewpoint of efficiently promoting the reaction. In order to discharge, it is effective to circulate nitrogen gas in the reactor. The flow rate of nitrogen gas is usually 0.0001% or more, preferably 0.001% or more, and usually 5% or less, preferably 3% or less, as a ratio of nitrogen flow volume per minute to the reaction vessel volume. It is a range. Nitrogen to be used is preferably of high purity, but nitrogen produced from liquid nitrogen may be used for inexpensive production.

[2. Conductive support]
The conductive support used in the electrophotographic photosensitive member of the present invention (hereinafter referred to as “the conductive support of the present invention” as appropriate) can be formed of any material having conductivity. Specific examples of the material for the conductive support include, for example, metal materials such as aluminum and aluminum alloys; resins, glass, paper, and the like, on which a conductive material such as aluminum is vapor-deposited or applied. . In addition, if possible, a conductive material having an appropriate resistance value is applied to the surface of a conductive support made of a metal material for the purpose of controlling conductivity, surface properties, etc. or for covering defects. You may use what you did.

Among these, it is preferable to use a metal material such as an aluminum alloy as the conductive support in terms of performance, material procurement, and cost.
In addition, the material of an electroconductive support body may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

Further, the form of the conductive support is also arbitrary, and for example, a drum shape, a sheet shape, a belt shape or the like is used.
Furthermore, the conductive support of the present invention is subjected to anodizing treatment and sealing treatment. This makes it possible to improve image characteristics and stabilize electrical characteristics when forming an image using the electrophotographic photosensitive member of the present invention.

  The anodizing treatment can be carried out by any method, but is usually carried out by energizing in an acidic bath using the conductive support as an electrode. Although there is no restriction | limiting in particular about an acidic bath, For example, acidic baths, such as chromic acid, a sulfuric acid, an oxalic acid, a boric acid, sulfamic acid, are mentioned. Of these, anodizing in sulfuric acid gives the best results.

For example, in the case of anodizing a conductive support made of aluminum in sulfuric acid, the treatment conditions are as follows: the sulfuric acid concentration is 100 g / L to 300 g / L, and the dissolved aluminum concentration is 2 g / L to 15 g / L. L, the liquid temperature is preferably set to 15 ° C. to 30 ° C., the electrolysis voltage is set to 10 V to 20 V, and the current density is preferably set within a range of 0.5 A / dm ^{2 to 2} A / dm ² . However, the processing conditions during the anodizing treatment are not limited to this.
By performing the anodizing treatment in this way, an anodized film is formed on the surface of the conductive support.

  The conductive support of the present invention is subjected to a sealing treatment after an anodized film is formed on the surface by an anodizing treatment. The sealing treatment can be carried out by any method, but is usually carried out by immersing the conductive support in a sealing agent aqueous solution (sealing solution) containing a sealing agent. A typical example is a low-temperature sealing treatment in which a conductive support is immersed in a sealant aqueous solution at a low temperature, or a high-temperature sealing in which a conductive support is immersed in a sealant aqueous solution at a high temperature. Processing.

(Low temperature sealing treatment)
As described above, the low temperature sealing treatment is performed by immersing the conductive support in an aqueous sealing agent solution at a low temperature.
In the low temperature sealing treatment, nickel fluoride is usually used as a main component as a sealing agent.
At this time, the concentration of the sealing agent in the aqueous sealing agent solution used in the case of the low temperature sealing treatment is arbitrary, but it is usually most effective to carry out in the range of 3 g / L to 6 g / L. is there.
In order to smoothly proceed with the sealing treatment, the treatment temperature is usually 25 ° C. or higher, preferably 30 ° C. or higher, and usually 40 ° C. or lower, preferably 35 ° C. or lower.

Further, the pH of the aqueous sealant solution is usually 4.5 or more, preferably 5.5 or more, and usually 6.5 or less, preferably 6.0 or less. In addition, there is no restriction | limiting in the pH regulator used when adjusting pH, Although arbitrary things can be used, For example, oxalic acid, boric acid, formic acid, acetic acid, sodium hydroxide, sodium acetate, aqueous ammonia etc. are used. be able to.
Further, the treatment time is arbitrary, but it is preferable to carry out the treatment usually within a range of 1 minute to 3 minutes per 1 μm of film thickness.

However, the sealing agent aqueous solution may contain substances other than the sealing agent. For example, in order to further improve the physical properties of the coating, a metal salt such as cobalt fluoride, cobalt acetate, or nickel sulfate, a surfactant, or the like may be mixed in the additive aqueous solution.
After the immersion, washing with water and drying are performed to finish the low temperature sealing treatment.

(High temperature sealing treatment)
On the other hand, the high temperature sealing treatment is performed by immersing the conductive support in an aqueous sealing agent solution at a high temperature.
In the high-temperature sealing treatment, a metal salt such as nickel acetate, cobalt acetate, lead acetate, nickel acetate-cobalt, and barium nitrate can be used as the sealing agent, but usually nickel acetate is used as a main component.
At this time, the concentration of the sealing agent in the aqueous sealing agent solution used in the case of the high temperature sealing treatment is arbitrary, but it is usually most effective to carry out in the range of 5 g / L to 20 g / L. is there.
In order to smoothly proceed with the sealing treatment, the treatment temperature is usually 80 ° C. or higher, preferably 85 ° C. or higher, and usually 100 ° C. or lower, preferably 98 ° C. or lower.

Furthermore, the pH of the aqueous sealant solution is usually 4.5 or more, preferably 5.0 or more, and usually 6.5 or less, preferably 6.0 or less. In addition, there is no restriction | limiting in the pH adjuster used when adjusting pH, Although arbitrary things can be used, For example, the thing similar to the case of a low temperature sealing process can be used.
Further, the treatment time is arbitrary, but the treatment is usually performed for 1 second or more, preferably 2 seconds or more, per 1 μm of film thickness.

However, as in the case of the low temperature sealing treatment, the sealing agent aqueous solution may contain a substance other than the sealing agent in the high temperature sealing treatment. For example, in order to further improve the physical properties of the film, sodium acetate, an organic carboxylate or the like, an anionic or nonionic surfactant or the like may be mixed in the additive aqueous solution.
After the immersion, the high-temperature sealing treatment is completed by washing with water and drying.

  When the average film thickness of the anodic oxide coating is thick, stronger sealing conditions are required due to higher concentration of the sealing liquid and high temperature / long time treatment. Therefore, productivity is reduced and surface defects such as blots, dirt, and dusting are likely to occur on the coating surface. From such points, it is desirable that the average thickness of the anodic oxide coating is usually 20 μm or less, preferably 7 μm or less.

(Roughening)
The surface of the conductive support may be smooth, but may be roughened in advance before the anodizing treatment. The surface roughening method is arbitrary, but the surface can be roughened by using, for example, a special cutting method or performing a polishing process. Further, it is possible to roughen the surface by mixing particles having an appropriate particle diameter with the material constituting the conductive support. Furthermore, in order to reduce the cost, it is also possible to use the drawn tube as it is as a conductive support without cutting. In particular, when using a non-cutting aluminum substrate such as drawing, impact machining, ironing, etc., the treatment eliminates dirt, foreign matter and other foreign matter, small scratches, etc., and a uniform and clean conductive support. Since it is obtained, it is preferable.

[3. Undercoat layer]
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 in an arbitrary combination and ratio.

Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable.
The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicone. The treatment applied to the titanium oxide particles may be one type, or two or more types of treatments may be performed in any combination and degree.
Further, as the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. In addition, the titanium oxide particles may have only one crystal type, or two or more crystal types may be included in any combination and ratio.

  Various metal oxide particle sizes can be used. Among them, the properties of the binder resin that is the raw material for the undercoat layer, and the stability of the coating solution used when the undercoat layer is formed by coating. Therefore, the average primary particle size is usually 10 nm or more, preferably 20 nm or more, and usually 100 nm or less, preferably 25 nm or less.

  The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. Examples of the binder resin used for the undercoat layer include phenoxy, epoxy, polyvinyl pyrrolidone, polyvinyl alcohol, casein, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, and polyamide. 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 polyamide, modified polyamide, and the like are preferable because they exhibit good dispersibility and coating properties.

  The mixing ratio of the metal oxide particles to the binder resin used in the undercoat layer can be arbitrarily selected, but it is usually used in the range of 10% by weight to 500% by weight in order to improve the stability of the coating solution and the coating properties. It is preferable in terms of

  Furthermore, the thickness of the undercoat layer can be arbitrarily selected, but it is usually from the viewpoint of improving the electrical characteristics, strong exposure characteristics, image characteristics, and repeat characteristics of the electrophotographic photosensitive member, and coating properties during production. Is 0.1 μm or more, preferably 0.5 μm or more, and usually 20 μm or less, preferably 10 μm or less. Moreover, you may mix a well-known antioxidant etc. in an undercoat layer.

[4. Photosensitive layer]
Next, the photosensitive layer formed on the conductive support (on the undercoat layer when the above-described undercoat layer is provided) will be described.
The photosensitive layer is a layer containing at least one of the above-described tetraphenylbenzidine derivatives of the present invention as a charge transport material, and the type thereof includes a charge generation material and a charge transport material in the same layer, A single layer type in which the charge generating material is dispersed in a binder resin, and a stacked type comprising a charge generating layer in which the charge generating material is dispersed in a binder resin and a charge transport layer in which the charge transporting material is dispersed in the binder resin. Any of these may be used. In general, it is known that the charge transport material exhibits the same performance as a charge transfer function regardless of whether it is a single layer type or a multilayer type.

  In addition, as the laminated photosensitive layer, a charge generation layer and a charge transport layer are laminated in this order from the conductive support side, and a charge transport layer and a charge generation layer are laminated in this order. There are reverse laminated type photosensitive layers, and any of them can be adopted, but a forward laminated type photosensitive layer capable of exhibiting the most balanced photoconductivity is preferable.

(Charge generation layer)
In the case of a multilayer photoreceptor, the charge generation layer is prepared by dispersing a charge generation material in a solution obtained by dissolving a binder resin in an organic solvent to prepare a coating solution, or after dispersing the charge generation material in an organic solvent. The liquid is mixed with a binder resin or a liquid obtained by dissolving the binder resin in an organic solvent to prepare a coating liquid, which is coated on a conductive support, and a charge generating substance is bound with various binder resins. It is formed by.

  Any known charge generating substance can be used, and examples thereof include selenium and its alloys, cadmium sulfide, other inorganic photoconductive materials, and organic photoconductive materials such as organic pigments. Of these, organic photoconductive materials are preferred, and organic pigments are particularly preferred. Specific examples of the organic pigment include phthalocyanine pigment (phthalocyanine compound), azo pigment, dithioketopyrrolopyrrole pigment, squalene pigment, quinacridone pigment, indigo pigment, perylene pigment, polycyclic quinone pigment, anthanthrone pigment, benzimidazole And pigments.

  Among the organic pigments exemplified above, a phthalocyanine pigment or an azo pigment is particularly preferable as the charge generation material. The phthalocyanine pigment is a point that a highly sensitive electrophotographic photosensitive member can be obtained with respect to a laser beam having a relatively long wavelength of 600 nm to 900 nm, and the azo pigment is a white light and a relatively short wavelength of 300 nm to 500 nm. Each is excellent in that it has sufficient sensitivity to laser light.

  When a phthalocyanine compound is used as the charge generation material, specifically, a metal such as metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, or an oxide, halide, hydroxide thereof And various crystal forms of coordinated phthalocyanines such as alkoxides. In particular, titanyl phthalocyanines (also known as oxytitanium) such as X-type, τ-type metal-free phthalocyanine, A-type (also known as β-type), B-type (also known as α-type), and D-type (also known as Y-type), which are highly sensitive crystal types Phthalocyanine), vanadyl phthalocyanine, chloroindium phthalocyanine, chlorogallium phthalocyanine such as type II, hydroxygallium phthalocyanine such as type V, μ-oxo-gallium phthalocyanine dimer such as type G and I, μ-oxo such as type II -Aluminum phthalocyanine dimer is preferred.

  Of these phthalocyanine compounds, the A type (β type) shows a clear peak at a diffraction angle 2θ (± 0.2 °) of powder X-ray diffraction at 9.3 °, 10.6 °, and 26.3 ° C. ), B-type (α-type), D-type (Y-type) oxytitanium phthalocyanine, II-type chlorogallium having a clear peak at a diffraction angle 2θ (± 0.2 °) of powder X-ray diffraction of 27.3 ° Particularly preferred are phthalocyanine, V-type hydroxygallium phthalocyanine, G-type μ-oxo-gallium phthalocyanine dimer, and the like. In particular, from the viewpoint of image improvement, it is preferable to use A-type (β-type), B-type (α-type), and D-type (Y-type) oxytitanium phthalocyanine, and mixtures thereof.

  As the phthalocyanine compound, one kind of compound may be used alone, or plural kinds of compounds may be used in a mixed or mixed crystal state. In addition, the phthalocyanine compound may be used as a mixed state in the crystalline state by mixing each component later, or in a mixed state in the phthalocyanine compound production / treatment process such as synthesis, pigmentation, and crystallization. It can be stuffed. 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, two types of crystals are mixed, mechanically ground and made amorphous, and then converted into a specific crystal state by solvent treatment. The method of doing is mentioned.

  On the other hand, when an azo pigment is used as the charge generation material, various known bisazo pigments and trisazo pigments are preferably used. When an azo pigment is used as the charge generation material, various known bisazo pigments and trisazo pigments are preferably used. Examples of preferred azo pigments are shown below.

Further, the charge generation materials may be used alone or in combination of two or more in any combination and ratio.
By the way, when an organic pigment is used as the charge generation material, these fine particles are used in a form bound with a binder resin. The type of binder resin is not particularly limited. For example, polyester resin, polyvinyl acetate, polyacrylic ester, polymethacrylic ester, polyester, polycarbonate, polyvinyl acetoacetal, polyvinyl propional, polyvinyl butyral, phenoxy resin, epoxy resin, urethane resin , Cellulose ester, cellulose ether and the like.

The usage ratio of the charge generating material to the binder resin is usually in the range of 30 to 500 parts by weight of the charge generating material with respect to 100 parts by weight of the binder resin in the case of the multilayer photoreceptor. In the case of a single layer type photoreceptor to be described later, the charge generation material is usually 0.1 parts by weight or more, preferably 1 part by weight or more, and usually 30 parts by weight or less, preferably 10 parts by weight based on 100 parts by weight of the binder resin. Less than parts by weight.
The thickness of the charge generation layer is usually 0.1 μm or more, preferably 0.15 μm or more, and usually 1 μm or less, preferably 0.6 μm or less.

(Charge transport layer)
The charge transport layer of the multilayer photoreceptor contains a charge transport material and usually contains a binder resin and other components used as necessary. Specifically, such a charge transport layer is prepared by, for example, preparing a coating solution by dissolving or dispersing a charge transport material and a binder resin in a solvent. In addition, in the case of a reverse lamination type photosensitive layer, it can be obtained by coating and drying on a conductive support (on the undercoat layer when an undercoat layer is provided).

As the charge transport material, the tetraphenylbenzidine derivative of the present invention is used.
In addition to the tetraphenylbenzidine derivative, other known charge transport materials may be used in combination. When other charge transport materials are used in combination, the kind thereof is not particularly limited. For example, carbazole derivatives, hydrazone compounds, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, and those obtained by bonding a plurality of these derivatives are preferable. More specifically, compounds described in JP-A-2-230255, JP-A-63-225660, JP-A-58-198043, JP-B-58-32372, and JP-B-7-21646 Are preferably used.

The binder resin is used for securing the film strength. Usually, the charge transport layer can be obtained by coating and drying a coating solution obtained by dissolving or dispersing a charge transport material and the binder resin in a solvent.
Examples of the binder resin include polymers and copolymers of vinyl compounds such as butadiene, styrene, vinyl acetate, vinyl chloride, acrylic acid ester, methacrylic acid ester, vinyl alcohol, and ethyl vinyl ether, polyvinyl butyral, polyvinyl formal, and partially modified polyvinyl. Examples include acetal, polycarbonate, polyester, polyarylate, polyamide, polyurethane, cellulose ether, phenoxy resin, silicon resin, epoxy resin, and poly-N-vinylcarbazole resin. Of these, polycarbonate and polyarylate are particularly preferred. These can also be used after being crosslinked with heat, light or the like using an appropriate curing agent or the like. Moreover, these binders may be used individually by 1 type, and 2 or more types can also be used together by arbitrary combinations and a ratio.

  The ratio of the binder resin to the charge transport material is 20 parts by weight or more of the charge transport material with respect to 100 parts by weight of the binder resin. Among these, 30 parts by weight or more is preferable from the viewpoint of residual potential reduction, and 40 parts by weight or more is more preferable from the viewpoint of stability and charge mobility when repeatedly used. On the other hand, from the viewpoint of thermal stability of the photosensitive layer, the charge transport material is usually used at a ratio of 150 parts by weight or less. Among these, 110 parts by weight or less is preferable from the viewpoint of compatibility between the charge transport material and the binder resin, 80 parts by weight or less is more preferable from the viewpoint of printing durability, and 70 parts by weight or less is most preferable from the viewpoint of scratch resistance.

  In addition, when the tetraphenylbenzidine derivative of the present invention is used in combination with another charge transport material, the ratio of the tetraphenylbenzidine derivative and the other charge transport material is arbitrary, but the tetraphenylbenzidine derivative of the present invention is usually 20%. % By weight or more, preferably 40% by weight or more, and usually 95% by weight or less, preferably 90% by weight or less.

  The thickness of the charge transport layer is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more, and usually 50 μm or less, preferably 45 μm or less from the viewpoint of long life, image stability, and high resolution. Further, the range is 30 μm or less.

(Photosensitive layer of single layer type photoreceptor)
In addition to the charge generation material and the charge transport material, the photosensitive layer of the single-layer photoconductor is formed using a binder resin in order to ensure film strength, in the same manner as the charge transport layer of the multilayer photoconductor. Specifically, a coating solution is usually prepared by dissolving or dispersing a charge generating substance, a charge transporting substance, and various binder resins in a solvent, and then on a conductive support (if an undercoat layer is provided, an undercoat layer is provided). It can be obtained by applying and drying the above.

  The types of the charge transport material and the binder resin and the use ratios thereof are the same as those described for the charge transport layer of the multilayer photoreceptor. The charge generating material is further dispersed in the charge transport medium comprising these charge transport material and binder resin.

  As the charge generation material, the same materials as those described for the charge generation layer of the multilayer photoreceptor can be used. However, in the case of a photosensitive layer of a single-layer type photoreceptor, it is desirable to sufficiently reduce the particle size of the charge generating material. Specifically, the range is usually 1 μm or less, preferably 0.5 μm or less.

If the amount of the charge generating material dispersed in the single-layer type photosensitive layer is too small, sufficient sensitivity cannot be obtained, but if it is too large, there are adverse effects such as a decrease in chargeability and a decrease in sensitivity. It is usually used in the range of 0.5% by weight or more, preferably 1% by weight or more, and usually 50% by weight or less, preferably 20% by weight or less based on the whole layer-type photosensitive layer.
Further, the film thickness of the single-layer type photosensitive layer is usually 5 μm or more, preferably 10 μm or more, and usually 100 μm or less, preferably 50 μm or less.

  For the purpose of improving film forming properties, flexibility, coating properties, contamination resistance, gas resistance, light resistance, etc., in both the photosensitive layer and the layers constituting the photosensitive layer, both of the multilayer type photosensitive member and the single layer type photosensitive member. Additives such as well-known antioxidants, plasticizers, ultraviolet absorbers, electron-withdrawing compounds, leveling agents, and visible light shielding agents may be included.

[5. Other layers]
In addition, in both the laminated type photoreceptor and the single layer type photoreceptor, the photosensitive layer formed by the above-described procedure may be the uppermost layer, that is, the surface layer, but another layer is provided on the photosensitive layer, and this is used as the surface layer. Also good.
For example, a protective layer may be provided for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to discharge products generated from a charger or the like.
Further, for the purpose of reducing frictional resistance and wear on the surface of the electrophotographic photosensitive member, a resin such as a fluorine-based resin or a silicone resin, or particles made of these resins or particles of an inorganic compound may be included in the surface layer. . Alternatively, a layer containing these resins and particles may be newly formed as a surface layer.

[6. Formation method of each layer]
Each layer constituting these electrophotographic photosensitive members is formed by immersing, coating, spraying, nozzle coating, bar coating, roll coating, blade coating a coating solution obtained by dissolving or dispersing a substance to be contained in a solvent. It is formed by sequentially coating by a known method such as coating.

  There is no particular limitation on the solvent used for preparing the coating solution, that is, the solvent or the dispersion medium. Specific examples include alcohols such as methanol, ethanol, propanol and 2-methoxyethanol, tetrahydrofuran, 1,4-dioxane, Ethers such as dimethoxyethane, esters such as methyl formate and ethyl acetate, ketones such as acetone, methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as benzene, toluene and xylene, dichloromethane, chloroform, 1,2-dichloroethane, Chlorinated hydrocarbons such as 1,1,2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, trichloroethylene, n-butylamine, isopropanolamine, diethylamine, triethanolamine Ethylenediamine, nitrogen-containing compounds such as triethylenediamine, acetonitrile, N- methylpyrrolidone, N, N- dimethylformamide, aprotic polar solvents such as dimethyl sulfoxide and the like. Moreover, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and kinds.

In addition, the amount of solvent used is not particularly limited, but considering the purpose of each layer and the properties of the selected solvent, it may be appropriately adjusted so that the physical properties such as the solid content concentration and viscosity of the coating solution are within a desired range. preferable.
For example, in the case of a photosensitive layer of a single layer type photoreceptor and a charge transport layer of a laminated type photoreceptor, the solid content concentration of the coating liquid or dispersion is usually 10% by weight or more, preferably 15% by weight or more. The range is usually 40% by weight or less, preferably 35% by weight or less. Further, the viscosity of the coating liquid or dispersion is usually in the range of 50 cps or more, preferably 100 cps or more, and usually 500 cps or less, preferably 400 cps or less.

  In the case of a charge generating layer of a multilayer photoreceptor, the solid content concentration of the coating solution or dispersion is usually 1% by weight or more, preferably 2% by weight or more, and usually 15% by weight or less, preferably 10%. The range is not more than% by weight. Further, the viscosity of the coating liquid or dispersion is usually in the range of 0.1 cps or more, preferably 0.5 cps or more, and usually 10 cps or less, preferably 8 cps or less.

  The coating solution is preferably dried at room temperature, after being statically dried at room temperature, usually in a temperature range of 30 ° C. or higher and 200 ° C. or lower for 1 minute to 2 hours, statically or under air blowing. The heating temperature may be constant or the heating may be performed while changing the temperature during drying.

[II. 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 (charging unit) 2, an exposure device (exposure unit) 3, and a developing device (developing unit) 4. Accordingly, a transfer device 5, a cleaning device 6, and a fixing device 7 are 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 electrophotographic photosensitive member 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 photoreceptor 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. In FIG. 1, a roller type charging device (charging roller) is shown as an example of the charging device 2, but other corona charging devices such as corotrons and scorotrons, contact type charging devices such as charging brushes and charging films are also preferred. Used.

  In many cases, the electrophotographic photosensitive member 1 and the charging device 2 are cartridges having both of them (the electrophotographic photosensitive member cartridge of the present invention; hereinafter referred to as “photosensitive cartridge” as appropriate), and the main body of the image forming apparatus. Designed to be removable from. However, the charging device 2 may be provided separately from the cartridge, for example, in the main body of the image forming apparatus. For example, when the electrophotographic photoreceptor 1 or the charging device 2 deteriorates, the photoreceptor cartridge can be removed from the image forming apparatus main body, and another new photosensitive cartridge can be mounted on the image forming apparatus main body. ing. Also, the toner described later is often stored in the toner cartridge and designed to be removable from the main body of the image forming apparatus. When the toner in the used toner cartridge runs out, this toner cartridge is removed. It can be removed from the main body of the image forming apparatus and another new toner cartridge can be mounted. Further, a cartridge equipped with all of the electrophotographic photosensitive member 1, the charging device 2, and the toner may be used.

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

  The type of the developing device 4 is not particularly limited as long as it can develop the exposed electrostatic latent image on the electrophotographic photosensitive member 1 into a visible image. Specific examples include dry development methods such as cascade development, one-component conductive toner development, and two-component magnetic brush development, and wet development methods. 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 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. However, the developing roller 44 and the electrophotographic photosensitive member 1 may not be in contact with each other but may be close to each other. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism (not shown). The supply roller 43 carries the stored toner T and supplies it to the developing roller 44. The developing roller 44 carries the toner T supplied by the supply roller 43 and contacts the surface of the electrophotographic photosensitive member 1.

  The regulating member 45 is formed of a resin blade such as 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. This regulating member 45 normally abuts against 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 provided as necessary, and 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 toner T is arbitrary, and besides the pulverized toner, a polymerized toner using a suspension polymerization method, an emulsion polymerization method, or the like can be used. In particular, when a polymerized toner is used, a toner having a small particle diameter of about 4 μm to 8 μm is preferable, and the toner particles are used in a variety of shapes from a nearly spherical shape to a shape outside the potato-like spherical shape. be able to. The polymerized toner is excellent in charging uniformity and transferability and is suitably used for high image quality.

  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 disposed so as 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 scrapes the residual toner adhering to the electrophotographic photosensitive member 1 with a cleaning member and collects the residual toner. If there is little or almost no residual toner, 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. Each of the upper and lower fixing members 71 and 72 includes a fixing roll in which a metal base tube such as stainless steel or aluminum is coated with silicon rubber, a fixing roll in which Teflon (registered trademark) resin is coated, and a fixing sheet. A member can be used. Further, each of the fixing members 71 and 72 may be configured to supply a release agent such as silicone oil in order to improve releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

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

  In the electrophotographic apparatus configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the electrophotographic photosensitive member 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 electrophotographic photosensitive member 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. Then, development of the electrostatic latent image formed on the photosensitive surface of the electrophotographic photoreceptor 1 is performed by the developing device 4.

  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 electrophotographic photosensitive member 1). Negatively charged) and conveyed while being carried on the developing roller 44 and brought into contact with the surface of the electrophotographic photosensitive member 1.

When the charged toner T carried on the developing roller 44 contacts the surface of the electrophotographic photoreceptor 1, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the electrophotographic 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 electrophotographic photosensitive member 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.
However, an image forming apparatus using reversal development is particularly effective in the characteristics of the photoreceptor of the present invention.

  In this embodiment, the electrophotographic photosensitive member cartridge of the present invention has been described by exemplifying the photosensitive member cartridge including the electrophotographic photosensitive member 1 and the charging device 2. However, the electrophotographic photosensitive member cartridge of the present invention is electrophotographic. The photosensitive member 1 may be provided with at least one of a charging device (charging unit) 2, an exposure device (exposure unit) 3, and a developing device (developing unit) 4. Specifically, for example, the electrophotographic photosensitive member cartridge of the present invention includes all of the electrophotographic photosensitive member 1, the charging device (charging unit) 2, the exposure device (exposure unit) 3, and the developing device (developing unit) 4. You may comprise as a cartridge.

  Hereinafter, the present invention will be described in more detail with reference to production examples, examples and comparative examples. In addition, this invention is not limited to the Example shown here, In the range which does not deviate from the summary of this invention, it can change arbitrarily and can implement.

<Manufacture of charge transport materials>
Production Example A (Exemplary Compound 1)
While mechanically stirring under ice-cooling, 122.0 g of 3,4-xylidine was added to acetic anhydride 219.
Dissolved in ml. Thereafter, the reactor was heated to 150 ° C., refluxed at the same temperature for another 10 hours, and cooled to room temperature. 100 ml of toluene and 200 ml of water were added to the reaction mixture, and the mixture was stirred for about 1 hour and separated. The organic layer was transferred to a 500 ml beaker, and with stirring, a saturated sodium bicarbonate solution was slowly poured and neutralized until the pH was weakly basic. Thereafter, the layers were separated, and the organic layer was washed three times with 100 mL / time of water, dried over magnesium sulfate, and concentrated under reduced pressure. To the obtained oily substance, 70 mL of a mixed solution of toluene / hexane (1/2) was added, and the mixture was stirred under ice-cooling. The precipitated white crystals were separated by filtration, and N-acetyl-3,4-xylidine 131. 0 g was obtained.

  Under a nitrogen atmosphere, 24.8 g of the obtained N-acetyl-3,4-xylidine, 33.2 g of 3-iodotoluene, 4.9 g of copper powder, and 42.0 g of potassium carbonate were mixed, The mixture was heated and stirred for 5 hours. While cooling to room temperature and stirring, 200 ml of toluene was added, and the insoluble material was filtered and concentrated under reduced pressure. To the obtained oil, 2-propanol (100 mL) and potassium hydroxide (10.2 g) were added, and the mixture was further heated to reflux for 3 hours. After cooling to room temperature, 100 ml of toluene and 150 ml of water were added to separate the layers. The organic layer was washed 3 times with 50 mL / time of water, dried over magnesium sulfate, and concentrated under reduced pressure. The obtained oil was dissolved in a mixed solution of toluene / hexane (1/1) and then passed through column chromatography (silica gel 700 g, developing solvent: toluene / hexane = 1/1) to give N- (3-tolyl). 29.9 g of -N- (3,4-xylyl) amine was obtained as a pale yellow oil.

  Under a nitrogen atmosphere, in a 500 ml four-necked flask, 200 ml of xylene, 16.2 g of 4,4′-diiodobiphenyl, 17.4 g of N- (3-tolyl) -N- (3,4-xylyl) amine, and Then, 9.2 g of sodium-tert-butoxide was added, and 20 ml of xylene solution containing 18 mg of palladium acetate and 64 mg of tri-tert-butylphosphine was added with stirring. Thereafter, the reactor was heated to 120 ° C. and continued to be heated at that temperature for 2 to 3 hours to be reacted. After completion of the reaction, the reaction mixture was cooled, and 200 ml of toluene and 200 ml of water were added for liquid separation. The organic layer was washed with 100 mL / time of water three times, dried over magnesium sulfate, and concentrated under reduced pressure. The obtained crude product was dissolved in 20 mL of a toluene / hexane (1/1) mixed solution, and then passed through column chromatography (silica gel 1 kg, developing solvent: toluene / hexane = 1/1) to give Exemplified Compound 1 Obtained (22.0 g, 96% yield).

Production Example B (Exemplary Compound 2)
The same operation as in Production Example A was performed to obtain N-acetyl-3,4-xylidine.
Thereafter, 33.2 g of 4-iodotoluene was used instead of 3-iodotoluene, and the production example was conducted except that the heating and stirring at 180 ° C. was performed for 7 to 8 hours in a nitrogen atmosphere which was performed for 4 to 5 hours in Production Example A. A. The same operation as in A was performed, and instead of N- (3-tolyl) -N- (3,4-xylyl) amine, N- (4-tolyl) -N- (3,4-xylyl) amine 7 g was obtained.
Subsequently, 17.4 g of N- (4-tolyl) -N- (3,4-xylyl) amine was used instead of N- (3-tolyl) -N- (3,4-xylyl) amine, and a xylene solution was used. Exemplified Compound 2 was obtained in the same manner as in Production Example A except that a xylene solution containing 18 mg of palladium acetate and 65 mg of tri-tert-butylphosphine was used (Example 2) (21.6 g, yield 94%) .

Production Example C (Exemplary Compound 4)
Exemplified compound 4 was obtained in the same manner as in Production Example A except that 17.4 g of 4,4'-diiodo-3,3'-dimethylbiphenyl was used in place of 4,4'-diiodobiphenyl. (21.8 g, 91% yield).

<Production of photoconductor>
Example 1
In X-ray diffraction, 0.5 part by weight of A-type oxytitanium phthalocyanine showing diffraction peaks at 9.3 °, 10.6 °, and 26.3 ° at a Bragg angle (2θ ± 0.2), and X-ray diffraction In addition, 9.5 parts by weight of D-type oxytitanium phthalocyanine having a diffraction peak at a Bragg angle (2θ ± 0.2) of 27.3 ° was added to 150 parts by weight of 4-methoxy-4-methylpentanone-2, and sand grind was added. The mill was dispersed for 1 hour in a mill.

  After the pulverization and dispersion treatment, 100 parts by weight of a 5 wt% 1,2-dimethoxyethane solution of polyvinyl butyral (“Decambutyral # 6000C” manufactured by Denki Kagaku Kogyo Co., Ltd.) as a binder resin, and phenoxy resin (Union Carbide) The charge generation layer coating solution was prepared by adding 100 parts by weight of a 5 wt% 1,2-dimethoxyethane solution of “PKHH” manufactured by the company.

  This coating solution was anodized in an aqueous sulfuric acid solution to anodize the surface, and an aluminum tube having a diameter of 3 cm and a length of 25.4 cm was subjected to high-temperature sealing at 90 ° C. in an aqueous nickel acetate solution (conducting material). The charge generation layer was formed by dip-coating on the conductive support) so that the film thickness after drying was 0.4 μm and drying.

Separately, 50 parts by weight of Exemplified Compound 1 obtained in Production Example 1 as a charge transport material and 2,2-bis (4-hydroxy-3-methylphenyl) propane shown below as a binder resin are used as aromatic diol components. unit (X ¹⁾ 51 mol% and 1,1-bis (4-hydroxyphenyl) -1-repeating units (X ²⁾ of the phenyl ethane and aromatic diol component p-t-butylphenol consists of a 49 mol% Polycarbonate resin having terminal structure derived from 100 parts by weight (viscosity average molecular weight 30,000) and 0.03 part by weight of silicone oil as a leveling agent in 640 parts by weight of tetrahydrofuran / toluene (weight ratio 8/2) mixed solvent The charge transport layer coating solution was prepared by dissolution.

  The coating solution is dip-coated on the charge generation layer so that the film thickness after drying is 20 μm, and dried to form a charge transport layer, whereby an electrophotographic photosensitive member having a laminated photosensitive layer is obtained. Manufactured.

  When this electrophotographic photosensitive member is mounted on a laser printer 4 (LJ4) manufactured by Hewlett-Packard Co., and an image forming test is performed on 10,000 sheets, there is no image defect or noise after forming 10,000 images. A good image was obtained. Subsequently, 10,000 sheets were continuously printed, but no image deterioration such as memory, fogging, and black spots was observed, and the image density was good and stable. These results are shown in Table 1. In Table 1, “◯” means “cannot be confirmed”, “Δ” means “barely recognized”, and “x” means “clearly recognized”.

(Example 2)
An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that Example Compound 2 obtained in Production Example B was used in place of Example Compound 1 obtained in Production Example A, and an image test was performed. The results are shown in Table 1.

Example 3
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that Example Compound 4 obtained in Production Example C was used in place of Example Compound 1 obtained in Production Example A, and an image test was performed. The results are shown in Table 1.

Example 4
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that Example Compound 7 was used in place of Example Compound 1 obtained in Production Example A, and an image test was performed. The results are shown in Table 1.

(Example 5)
Instead of Exemplified Compound 1 obtained in Production Example A, Exemplified Compound 11 exemplified in the Journal of Electrophotographic Society Vo130, No1 was used. Produced an electrophotographic photosensitive member in the same manner as in Example 1, and subjected an image test. The results are shown in Table 1.

(Example 6)
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the following charge transport material (b) exemplified in JP-A-6-214409 was used instead of the exemplified compound 1 obtained in Production Example A. Manufactured and image tested. The results are shown in Table 1.

(Comparative Example 1)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the following charge transport material (a) conventionally used was used instead of the exemplified compound 1 obtained in Production Example A, and an image test was performed. It was. The results are shown in Table 1.

(Comparative Example 2)
An electrophotographic photoreceptor is produced in the same manner as in Example 1 except that the following charge transport material (c) exemplified in JP-A-1-118141 is used instead of the exemplified compound 1 obtained in Production Example A. An image test was conducted. The results are shown in Table 1.

(Comparative Example 3)
In Example 1, an electrophotographic photosensitive member was produced and subjected to an image test in the same manner as in Example 1 except that the aluminum tube was not sealed. The results are shown in Table 1.

(Comparative Example 4)
Example 1 is the same as Example 1 except that the anodization treatment and sealing treatment were not performed on the aluminum tube, and the charge generation layer and the charge transport layer were formed after forming the undercoat layer according to the following procedure. An image test was conducted in the same manner. The results are shown in Table 1.

Undercoat layer:
On the conductive support, the following undercoat layer dispersion was applied by dip coating so that the film thickness after drying was 1.25 μm and dried to form an undercoat layer.
Dispersion for undercoat layer:
High-speed fluidized mixing of 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.) A surface milled titanium oxide obtained by mixing in a kneading machine ("SMG300" manufactured by Kawata Co., Ltd.) and mixing at a high speed at a rotational peripheral speed of 34.5 m / second is ball milled in a mixed solvent of methanol / 1-propanol. To obtain a dispersion slurry of hydrophobized titanium oxide. This dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene (weight ratio 7/1/2), and ε-caprolactam [compound represented by the following formula (A ^x )] / bis (4-amino-3- Methyl-cyclohexyl) methane [compound represented by the following formula (B ^x )] / hexamethylenediamine [compound represented by the following formula (C ^x )] / decamethylene dicarboxylic acid [compound represented by the following formula (D ^x )] / Octadecamethylenedicarboxylic acid [compound represented by the following formula (E ^x )] (composition polyamide% 75% / 9.5% / 3% / 9.5% / 3%) After stirring and mixing with heating to dissolve the polyamide pellets, the weight ratio of methanol / 1-propanol / toluene is 7/1 / by performing ultrasonic dispersion treatment. In, and a hydrophobic process containing titanium oxide / copolymer polyamide in a weight ratio of 3/1, for an undercoat layer dispersion having a solid content concentration of 18.0%.

  From Table 1, when a conductive support subjected to anodization treatment and sealing treatment is used, and the tetraphenylbenzidine derivative of the present invention is used as a charge transport material, the generation of memory, fogging, It can be seen that image defects such as black spots can be suppressed.

Here, the results of Table 1 will be examined in detail in comparison with the prior art.
For example, Patent Documents 1, 2, and 6 describe the use of a benzidine compound as a photoreceptor, but in this case, image characteristics such as image density and leak are not satisfactory, and in particular, repeatedly. There are problems in image formation, and there is also a problem in matching charge transport materials and charge generation materials.

Patent Document 3 describes a photoconductor using Exemplified Compound 12. However, there is a problem in the solubility of the charge transport material during production, and in the case of repeatedly forming an image, a pinhole is used. There was a high possibility of image defects (leakage).
Furthermore, Patent Documents 4 and 5 describe the use of a p-phenylenediamine derivative group as a photoreceptor, but when image formation is performed using the photoreceptor, dark attenuation is relatively large. When actually used as a photoreceptor, there was a risk of fogging.

  In contrast, the electrophotographic photosensitive member of the present invention uses an anodized treatment and a sealing treatment as a conductive support, and the tetraphenylbenzidine derivative of the present invention is used as a charge transport material, It is possible to suppress the occurrence of leakage and memory during image formation. Furthermore, by selecting an appropriate tetraphenylbenzidine derivative, it is possible to improve the image density in repeated image formation, matching between the charge transport material and the charge generation material, and the like.

  The present invention can be carried out in any field that requires an electrophotographic photosensitive member, and is suitable for use in, for example, a copying machine, a printer, a printing machine, and the like.

1 is a schematic diagram illustrating a main configuration of an embodiment of an image forming apparatus of the present invention.

Explanation of symbols

1 Photoconductor (Electrophotographic photoconductor)
2 Charging device (charging roller; charging unit)
3 Exposure equipment (exposure section)
4 Development device (development unit)
DESCRIPTION OF SYMBOLS 5 Transfer apparatus 6 Cleaning apparatus 7 Fixing apparatus 41 Developing tank 42 Agitator 43 Supply roller 44 Developing roller 45 Control member 71 Upper fixing member (fixing roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper (paper, medium)

Claims (7)

An electroconductive support subjected to anodizing treatment and sealing treatment;
And a layer containing at least one tetraphenylbenzidine derivative each having one or more substituents on a phenyl group bonded to a benzidine skeleton and formed on the conductive support. body. The electrophotographic photoreceptor according to claim 1, wherein the tetraphenylbenzidine derivative is a compound represented by the following formula [1].

(In the formula [1], Ar ¹ and Ar ² each independently represent a phenyl group having at least one substituent, and Ar ³ and Ar ⁴ each independently have a substituent. Also represents a good arylene group,

as well as

Each independently represents a phenyl group which may have a substituent other than Ra, and each Ra independently represents an alkyl group which substitutes the corresponding meta or para position of the phenyl group. ) The electrophotographic photosensitive member according to claim 2, wherein the compound is represented by the following formula [2].

(In the formula [2], R ¹ and R ² each independently represent a methyl group or a methoxy group, and R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or a methyl group. Represents.)   The electrophotographic photosensitive member according to claim 1, further comprising a layer containing oxytitanium phthalocyanine formed on the conductive support.   The oxytitanium phthalocyanine exhibits a diffraction peak at a Bragg angle (2θ ± 0.2) of 27.3 ° in the X-ray diffraction spectrum, or at 9.3 °, 10.6 °, and 26.3 °. The electrophotographic photosensitive member according to claim 4, which exhibits a diffraction peak. The electrophotographic photosensitive member according to any one of claims 1 to 5,
A charging unit for charging the electrophotographic photosensitive member, an exposure unit for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image, and developing the electrostatic latent image formed on the electrophotographic photosensitive member An electrophotographic photosensitive member cartridge comprising at least one of the developing units. The electrophotographic photosensitive member according to any one of claims 1 to 5,
A charging unit for charging the electrophotographic photosensitive member;
Exposing the charged electrophotographic photoreceptor to form an electrostatic latent image; and
An image forming apparatus comprising: a developing unit that develops an electrostatic latent image formed on the electrophotographic photosensitive member.

Images