JP2017027090A - Electrophotographic photoreceptor, electrophotographic photoreceptor cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor that maintains an adhesive property of a photosensitive layer extremely well irrespective of the magnitude of contraction, and to provide a process cartridge and an image forming apparatus using the electrophotographic photoreceptor.SOLUTION: There is provided an electrophotographic photoreceptor comprising at least an undercoat layer and a photosensitive layer on a conductive substrate, the electrophotographic photoreceptor containing a polyamide resin having a universal hardness based on the following measurement method of the undercoat layer of 55 N/mmor less. [measurement method] the universal hardness is a value defined by the following formula and obtained from the maximum indentation depth, when the undercoat layer is measured in the conditions of a maximum indentation load of 0.2 mN using a Vickers indenter, a time required for loading of 10 seconds, and a time required for unloading of 10 seconds under an environment of a temperature of 25°C and a relative humidity of 50%. Universal hardness (N/mm)=test load (N)/surface area of Vickers indenter under test load (mm).SELECTED DRAWING: None

Description

  The present invention relates to an electrophotographic photosensitive member, an electrophotographic photosensitive member cartridge, and an image forming apparatus. In particular, the present invention relates to an electrophotographic photosensitive member, an electrophotographic photosensitive member cartridge, and an image forming apparatus that are remarkably excellent in adhesiveness of a photosensitive layer.

  The electrophotographic technique is widely used in the fields of copiers, various printers, printing presses and the like because of its excellent immediacy and high quality images. As an electrophotographic photosensitive member that is the core of the electrophotographic technology, an electrophotographic photosensitive member using an organic photoconductive material having advantages such as non-pollution, easy film formation, and easy manufacture (hereinafter simply referred to as “ Also referred to as “photoreceptor”).

  As an electrophotographic photoreceptor using an organic photoconductive material, a so-called dispersion type single-layer photoreceptor in which a photoconductive fine powder is dispersed in a binder resin, a charge generation layer and a charge transport layer are laminated. Multilayer photoreceptors are known. Multilayer photoconductors provide highly efficient charge generating materials and wide and highly safe photoconductors. Also, photoconductors can be easily formed by coating, have high productivity, and are advantageous in terms of cost. This is the mainstream of photoconductors for the reasons described above, and has been developed and put into practical use.

  On the other hand, single-layer photoconductors are slightly inferior to multilayer photoconductors in terms of electrical characteristics and have a somewhat lower degree of freedom in material selection, but can generate charges near the surface of the photoconductor. Further, since the image is not blurred even if the film is thick, there is an advantage that high printing durability can be achieved by increasing the film thickness. In addition, the single-layer type photosensitive member requires fewer coating steps, is advantageous for interference fringes and tube defects derived from a conductive substrate (support), and can use an inexpensive substrate such as a non-cutting tube. For this reason, there is an advantage that the cost can be reduced.

  An electrophotographic photosensitive member using an organic photoconductive material has the above-mentioned advantages, but does not satisfy all the characteristics required for an electrophotographic photosensitive member, and in particular, it is repeatedly used in a copying machine or a printer. However, there is a problem that the photosensitive layer gradually deteriorates. Therefore, it is desired that the damage due to repeated use is small, the sensitivity is high, the residual potential is low, and the electrical characteristics are stable. These characteristics greatly depend on the charge generation material, the charge transport material, the additive, and the binder resin. As the charge generation material, a phthalocyanine pigment or an azo pigment is mainly used because it needs to have sensitivity to a light source for light input. Various types of charge transport materials are known, but amine compounds are widely used because they exhibit a very low residual potential (see, for example, Patent Document 1 and Patent Document 2).

Polyvinyl butyral resin is widely used as the binder resin for the charge generation layer of the multilayer photoconductor because of its excellent durability and solubility in solvents, etc. In addition, polyvinyl formal resins and polyester resins are also used. Various resins are used (Patent Documents 1 to 4).
Moreover, as binder resin used for an electric charge transport layer, polycarbonate resin and polyarylate resin are used suitably (patent document 2).

As described above, a number of charge generating materials, charge transporting materials, and binder materials such as binder resins (for example, Patent Documents 5 to 7) are known. Among them, it is known that the dark clouds have high performance. When used in combination, it is possible to provide an electrophotographic photosensitive member that has excellent electrophotographic photosensitive member characteristics and can provide a desired high-quality image when used in an image forming apparatus.

Do not mean. In particular, in recent years, improvement in wear resistance has been desired, and as one solution thereof, a binder resin having excellent wear resistance is used for the charge transport layer, and the content of the charge transport material is reduced. There is a technique that does not impair the performance of the binder resin as much as possible.

Japanese Patent Laid-Open No. 2000-075517 JP 2002-040688 A JP 2011-028041 A JP 2001-183854 A JP 2006-208474 A JP 2001-170041 A JP 2006-189595 A

However, according to the study by the present inventors, when a binder resin having excellent wear resistance is used, the shrinkage of the photosensitive layer is increased and the internal stress is increased, so that the adhesiveness of the photosensitive layer is deteriorated. Further, peeling occurs between the photosensitive layer and the undercoat layer or between the undercoat layer and the support. At the same time, a phenomenon was observed in which the electrical characteristics deteriorated significantly as the adhesiveness deteriorated.
The present invention has been made in view of the above problems. That is, an object of the present invention is to provide an electrophotographic photoreceptor in which the adhesiveness of the photosensitive layer is kept extremely good regardless of the size of the shrinkage, and furthermore, both good electrical characteristics and image characteristics are compatible. Another object of the present invention is to provide a process cartridge and an image forming apparatus using the electrophotographic photosensitive member.

The present inventors have found that an electrophotographic photoreceptor using an undercoat layer having a specific hardness can remarkably improve adhesion and is excellent in image characteristics.
That is, the gist of the present invention resides in the following three points.
(1) An electrophotographic photosensitive member having at least an undercoat layer and a photosensitive layer on a conductive support, wherein a universal hardness based on the following measurement method of the undercoat layer is 55 N / mm ² or less. Containing an electrophotographic photoreceptor.

[Measurement method]
Maximum when the undercoating layer is measured under the conditions of a temperature of 25 ° C. and a relative humidity of 50% using a Vickers indenter under conditions of a maximum indentation load of 0.2 mN, a load time of 10 seconds, and an unload time of 10 seconds. The value defined by the following formula from the indentation depth is the universal hardness.
Universal hardness (N / mm ² )
= Test load (N) / Vickers indenter surface area under test load (mm ² )
(2) The electrophotographic photosensitive member according to (1), 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 the electrophotographic An electrophotographic photosensitive member cartridge comprising: a developing unit that develops an electrostatic latent image formed on a photosensitive member; and at least one of a cleaning unit that cleans the electrophotographic photosensitive member.
(3) The electrophotographic photosensitive member according to 1 above, 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 the electrophotographic photosensitive member An image forming apparatus comprising: a developing unit that develops the electrostatic latent image formed on the body.

  The electrophotographic photosensitive member of the present invention can significantly improve the adhesion of the photosensitive layer by providing an undercoat layer having a specific hardness on a conductive support. It is possible to provide an electrophotographic photosensitive member cartridge and an image forming apparatus including the electrophotographic photosensitive member.

FIG. 1 is a curve showing the relationship between indentation depth and load when measuring the elastic change rate of a polyamide resin. FIG. 2 is a schematic diagram showing the main configuration of an embodiment of the image forming apparatus according to the present invention. FIG. 3 is a chart showing an X-ray diffraction peak when CuTα of a titanyl phthalocyanine pigment used in Examples is used as a radiation source.

Hereinafter, the embodiments of the present invention will be described in detail. However, the present invention is not limited to the following descriptions, and can be appropriately modified and implemented without departing from the gist of the present invention.
[Electrophotographic photoreceptor]
Hereinafter, the electrophotographic photoreceptor of the present invention will be described in detail.

<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. A conductive material having an appropriate resistance value may be applied to a conductive support of a metal material in order to control conductivity, surface properties, etc., or to cover defects.

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, it is formed by anodizing in an acidic bath of chromic acid, sulfuric acid, oxalic acid, boric acid, sulfamic acid, etc., but anodizing in sulfuric acid gives better results. In the case of anodic oxidation in sulfuric acid, the sulfuric acid concentration is 100-300 g / l, the dissolved aluminum concentration is 2-15 g / l, the liquid temperature is 15-30 ° C., the electrolysis voltage is 10-20 V, and the current density is 0.5-. Although it is preferable to set within the range of 2A / dm2, 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 normal method. For example, the low-temperature sealing treatment is performed by immersion in an aqueous solution containing nickel fluoride as a main component, or the high-temperature sealing is performed by immersion in an aqueous solution containing nickel acetate as a main component. It is preferable that the treatment is 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 are obtained when it is used in the range of 3-6 g / l. Further, in order to proceed the sealing treatment smoothly, the treatment temperature is 25-40 ° C., preferably 30-35 ° C., and the pH of the nickel fluoride aqueous solution is 4.5-6.5, preferably It is better 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 physical properties of the film, cobalt fluoride, cobalt acetate, nickel sulfate, a surfactant or 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 solution of a metal salt 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 in the range of 5-20 g / l. The treatment temperature is 80-100 ° C., preferably 90-98 ° C., and the pH of the nickel acetate aqueous solution is preferably 5.0-6.0. 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 as well, sodium acetate, organic carboxylic acid, anionic and nonionic surfactants 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, it is possible to use the drawing tube as it is without cutting. In particular, when using a non-cutting aluminum substrate such as drawing, impact processing, ironing, etc., it is preferable because the treatment eliminates dirt, foreign matter, and other foreign matters, small scratches, etc., and a uniform and clean substrate can be obtained. .

<Underlayer>
It is preferable to provide an undercoat layer between the conductive support and the photosensitive layer described later. As the undercoat layer, a resin, a resin in which particles such as a metal oxide are dispersed, or the like is used, and further includes a binder resin. These may be used alone or in combination with several particles of resin, metal oxide or the like. A conductive layer containing particles such as metal oxide and a binder resin and an intermediate layer containing a binder resin may be laminated to form an undercoat layer.

  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, and calcium titanate. And metal oxide particles containing a plurality of metal elements such as strontium titanate and barium titanate. These may use only one type of particles or a mixture of a plurality of types of particles. Among these metal 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.
As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. Moreover, the thing of a several crystal state may contain.

Various particle diameters of the metal oxide particles can be used. Among these, from the viewpoint of characteristics and liquid stability, the average primary particle diameter is preferably 10 nm or more and 100 nm or less, and particularly preferably 10 nm. It is 50 nm or less. This average primary particle size can be obtained from a TEM (transmission electron microscope) photograph or the like.
The addition ratio of the metal oxide particles to the binder resin used in the undercoat layer can be arbitrarily selected, but is usually 10% by mass with respect to the binder resin from the viewpoint of dispersion stability and coating properties. As mentioned above, it is preferable to use in the range of 500 mass% or less.

  The thickness of the undercoat layer is arbitrary as long as the effects of the present invention are not significantly impaired, but the viewpoint of improving the electrical characteristics, strong exposure characteristics, image characteristics, repeat characteristics, and coating properties during production of the electrophotographic photosensitive member. Therefore, it is usually 0.01 μm or more, preferably 0.1 μm or more, and usually 30 μm or less, preferably 20 μm or less. A known antioxidant or the like may be mixed in the undercoat layer. The undercoat layer may contain pigment particles, resin particles and the like for the purpose of preventing image defects.

<Polyamide resin>
The undercoat layer in the present invention contains a polyamide resin having an elastic deformation rate of 56.0% or more as a binder resin. The elastic deformation rate will be described later. For example, a polyamide resin having an elastic deformation rate of 56.0% or more can be made into a copolyamide resin by, for example, using a polyamide component as a hard segment and introducing a soft segment therein. Achieved. As the binder resin, a resin that may be included in addition to the polyamide resin will be described later.

The crystalline region in the polyamide resin is composed of hard segments, and when a soft segment is introduced there, the amorphous region between spherulites increases, so the elastic deformation rate is considered to increase.
Examples of the soft segment include an aliphatic polyester component or an aliphatic polyether that is a soft component exhibiting entropy elasticity. Especially, it is preferable from the point of the solubility to a solvent and adhesiveness that a polyamide resin contains polyether structures, such as aliphatic polyether.

Examples of the aliphatic polyester include aliphatic diols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-bis (hydroxymethyl) -cyclohexane, and dicarboxylic acids. And polycondensates of lactone compounds such as poly (ε-caprolactone).
Examples of the aliphatic polyether include polyether glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

  Among polyamide resins, alcohol-soluble copolymerized polyamide resins, modified polyamide resins, and the like are preferable because they exhibit good dispersibility and coating properties. In particular, a polyamide resin having a solid content concentration of 5% by mass when dissolved in a mixed solvent of methanol: toluene = 1: 1 (mass ratio) has a viscosity of 8.0 cP to 15.0 cP has good adhesion. It is preferable in keeping. Moreover, from a viewpoint of applicability | paintability, More preferably, it is 8.1 cP or more, Most preferably, it is 8.2 cP or more. Moreover, from a viewpoint of applicability | paintability, More preferably, it is 13.0 cP or less, Most preferably, it is 11.0 cP or less. If a polyamide resin having a too high viscosity of the solution is used, the stability of the coating solution for the undercoat layer is lowered, and the uniformity of the coating film may be deteriorated to deteriorate the adhesiveness. On the other hand, if the viscosity of the solution is too low, the viscosity of the coating solution for the undercoat layer becomes too low, so that only a photoconductor having a thin film thickness of the undercoat layer can be produced. There is a possibility that the effect of adhesion with the resin cannot be obtained.

In the undercoat layer, the ratio of the polyamide resin having an elastic deformation rate of 56.0% or more is generally 1% by mass or more, more preferably 10% by mass or more, and particularly preferably 25% in the total undercoat layer. It is at least mass%. This is because if the proportion of the polyamide resin having an elastic deformation rate of 56.0% or more is too small, the effect of improving adhesiveness described later cannot be obtained effectively. The upper limit is not particularly limited, but is usually 100% by mass or less, preferably 90% by mass or less, and more preferably 80% by mass or less from the viewpoint of coatability in the entire undercoat layer.
The lower limit of the polyamide resin having an elastic deformation rate of 56.0% or more is preferably 5 parts by mass or more, more preferably 25 parts by mass or more, with respect to 100 parts by mass of the entire binder resin. More preferred is part by mass or more. 100 parts by mass is particularly preferred.

<Elastic deformation rate and universal hardness>
The elastic deformation rate of the polyamide resin coating film contained in the undercoat layer in the present invention is 56.0% or more, more preferably 60.0% or more, and particularly preferably 65.0% or more. By setting the elastic deformation rate within the above range, the adhesion between the photosensitive layer and the conductive support can be remarkably improved. The upper limit is not particularly limited, but is usually 100% or less, preferably 90.0% or less, and more preferably 80.0% or less from the viewpoint of ease of production. The reason for this is not clear, but will be explained below.

In the production of an electrophotographic photoreceptor, a known manufacturing method undergoes a drying step. Is considered working. When the photosensitive layer is cut during the peel test, this stress acting on the undercoat layer and its interface is released.
When the elastic deformation rate of the resin of the undercoat layer is low, the undercoat layer is difficult to be deformed to a state with less strain. Therefore, the strain of the undercoat layer generated due to this shrinkage cannot be reduced. It is considered that the interface of this is likely to break.

On the other hand, when a resin having a high elastic deformation rate is contained in the undercoat layer, it is considered that the undercoat layer is easily deformed to a state with less strain, and thus is resistant to peeling. The problem of poor adhesiveness in actual use is also considered to be scratched, so it is practically effective not only in the peel test to contain a resin having a high elastic deformation rate in the undercoat layer. It seems to be a technique.
Further, the universal hardness of the undercoat layer is generally 55N / mm ^2, more preferably at most 50 N / mm ^2. The lower limit is not particularly limited, but is usually 1 N / mm ² or more, preferably 5 N / mm ² or more, more preferably 10 N / mm ² or more from the viewpoint of ease of production.

  The reason why the above range is preferable includes the following phenomena. The cause is not clear, but during the electrophotographic process, a force that pushes the photosensitive layer to the support side works with a cleaning blade or the like. The photosensitive layer may contain pigment particles or the like, but if the universal hardness of the undercoat layer is equal to or less than the upper limit, the pigment particles of the photosensitive layer are incorporated into the undercoat layer by the force to be pushed. It is thought that it becomes easy to enter. As a result, an anchor effect is obtained, and it is considered that the adhesiveness is improved.

In order to set the universal hardness of the undercoat layer to 55 N / mm ² or less, for example, it can be achieved by containing the polyamide resin having the elastic deformation rate of 56.0% or more in the undercoat layer. In addition, for example, when the soft segment is contained in the resin used for the undercoat layer and the content thereof increases, the universal hardness decreases. Further, it is considered that the universal hardness is lowered when the Tg (glass transition point) of the resin used for the undercoat layer is lower than or equal to room temperature. Further, when the content of the metal oxide contained in the undercoat layer increases, the universal hardness decreases. Thus, the universal hardness of 55 N / mm 2 or less can be achieved by various methods or by combining these methods.

The elastic deformation rate and universal hardness in the present invention are values measured using a micro hardness tester (Fischer: FISCHERSCOPE HM2000) in an environment of a temperature of 25 ° C. and a relative humidity of 50%.
In the case of elastic deformation, a polyamide resin is formed, and in the case of universal hardness, an undercoat layer is formed on a film having a thickness of 10 μm or more to obtain a measurement sample. For the measurement, a Vickers square pyramid diamond indenter having a facing angle of 136 ° is used. The measurement conditions are set as follows, and the load applied to the Vickers indenter and the indentation depth under the load are continuously read, and the profiles shown in FIG. 1 plotted on the Y axis and X axis are obtained. To do.

(Measurement conditions for polyamide resin coating film)
Maximum pushing load 5mN
Load time 10 seconds
Unloading time 10 seconds
(Measurement conditions for undercoat layer)
Maximum pushing load 0.2mN
Load time 10 seconds
Unloading time 10 seconds

The elastic deformation rate in the present invention is a value defined by the following formula based on the results obtained by the above measurement, and the work that the film performs elastically at the time of unloading with respect to the total work amount required for indentation. It is a ratio.
Elastic deformation rate (%) = (We / Wt) × 100
In the above formula, Wt represents the total work (nJ), and is represented by the area surrounded by A-B-D-A in FIG. We represents the work of elastic deformation (nJ) and is represented by the area surrounded by C-B-D-C in FIG.
The larger the elastic deformation rate, the less the deformation with respect to the load remains. The elastic deformation rate of 100% means that no deformation remains.

The polyamide resin coating used in the measurement of the elastic deformation rate in the present invention is obtained by dissolving the polyamide resin in a soluble solvent, and using an applicator or the like on a sturdy and flat support such as a glass plate, 10 μm. A film having a uniform film thickness can be used within the above film thickness range.
In the present invention, the universal hardness of the undercoat layer is a value defined by the following formula from the indentation depth using the value obtained when the indentation load is 0.2 mN among the results obtained by the above measurement. It is.
Universal hardness (N / mm ² ) = Test load (N) / Vickers indenter surface area under test load (mm ² )
The universal hardness of the undercoat layer can be measured, for example, by peeling off the photosensitive layer of the photosensitive drum with a solvent and exposing the undercoat layer to the outermost surface.

<Glass transition temperature (Tg) of polyamide resin>
The glass transition temperature (Tg) of the polyamide resin is the temperature at the intersection of two tangent lines by drawing a tangent line at the beginning of the transition (inflection) of the curve measured at a heating rate of 10 ° C./min in a differential scanning calorimeter. Can be obtained as

<Viscosity of polyamide resin solution>
The viscosity of the polyamide resin solution can be measured using a rotary viscometer under a measurement temperature of 25 ° C. That is, a solution of methanol / toluene = 1/1 (mass ratio) is prepared, and the polyamide resin to be measured is dissolved therein so as to be 5% by mass. This solution can be measured at an appropriate rotational speed using a rotary viscometer under the condition of a measurement temperature of 25 ° C., and the viscosity of the solution can be confirmed.

<Configuration of polyamide resin>
A known polyamide component can be used as the hard segment. For example, it is preferable to polymerize a unit derived from di- or tricarboxylic acid, a lactam compound, aminocarboxylic acid, diamine or the like to obtain a polyamide component.
The lactam and the aminocarboxylic acid generally have 2 or more carbon atoms, preferably 4 or more, and more preferably 6 or more from the viewpoints of economy and availability. The upper limit is usually 20 or less, preferably 16 or less, and more preferably 12 or less.

  For example, lactam compounds such as α-lactam, β-lactam, γ-lactam, δ-lactam, ε-lactam (caprolactam), ω-lactam (lauryllactam, dodecanlactam), 6-aminocaproic acid, 7-aminoheptanoic acid , 9-aminononanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and other aminocarboxylic acids. Caprolactam, dodecane lactam, 11-aminoundecanoic acid, and 12-aminododecanoic acid are preferred from the viewpoints of economy and availability. These can use 1 type (s) or 2 or more types. Among these, a single component (single structure) is preferable.

As the component amount of lactam and aminocarboxylic acid, the lower limit is usually 1 mol% or more of the total polyamide block, preferably 10 mol% or more, more preferably 30 mol% or more, particularly from the viewpoint of water resistance, wear resistance, and impact resistance. Preferably it is 50 mol% or more. The upper limit is usually 100 mol% or less of the total polyamide block, and is preferably 100 mol% from the viewpoint of economy and ease of production.

The di- or tricarboxylic acid has a carbon number of usually 2 or more, preferably 3 or more, and more preferably 4 or more from the viewpoints of economy and availability. The upper limit is usually 32 or less, preferably 26 or less, more preferably 22 or less.
For example, oxalic acid, malonic acid, succinic anhydride, maleic anhydride, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, 1,16-hexadecanedicarboxylic acid, 1,18- Saturated aliphatic di- or tricarboxylic acid such as octadecane dicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, pentadecenoic acid, hexadecenoic acid, heptadecenoic acid, octadecenoic acid, nonadecene Aliphatic monounsaturated fatty acids such as acids, eicosenoic acid, decadienoic acid, undecadienoic acid, dodecadienoic acid, tridecadienoic acid, tetradecadienoic acid, pentadecadienoic acid, hexadecadienoic acid, heptacadienoic acid, octadecadienoic acid, nonadecadienoic acid , Ikosajien acid, and di-unsaturated fatty acids, such as docosadienoic acid. These can use 1 type (s) or 2 or more types. From the viewpoint of improving the elastic deformation rate, saturated aliphatic di- or tricarboxylic acid is preferable. From the viewpoint of improving the elastic deformation rate, a linear saturated aliphatic dicarboxylic acid is preferable. Specifically, adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid are preferable from the viewpoint of ease of synthesis, and adipic acid is particularly preferable from the viewpoint of economy and availability. These can use a plurality of components.

As the amount of the dicarboxylic acid component, the lower limit is usually 1 mol% or more of the entire polyamide resin,
Preferably it is 3 mol% or more, More preferably, it is 5 mol% or more, Most preferably, it is 10 mol%
That's it. The upper limit is usually 50 mol% or less, preferably 45 mol% or less, more preferably 40 mol% or less, and particularly preferably 30 mol% or less of the entire polyamide resin.
As the diamine, the number of carbon atoms is usually 2 or more, preferably 4 or more, and more preferably 6 or more from the viewpoints of economy and availability. The upper limit is usually 32 or less, preferably 26 or less, more preferably 20 or less.

For example, ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine,
Linear methylenediamines such as dodecamethylenediamine, tridecamethylenediamine, tetradecamethylenediamine, pentadecamethylenediamine, hexadecamethylenediamine, heptacamethylenediamine, octadecamethylenediamine, nonadecamethylenediamine, eicosamethylenediamine, etc. 2- / 3-methyl-1,5-pentanediamine, 2-methyl-1,8-octanediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methyl-1, Examples include branched chain methylenediamine such as 9-nonanediamine. These can use 1 type (s) or 2 or more types. From the viewpoints of economy and availability, linear methylene diamine is preferable, and among these, hexamethylene diamine, nonamethylene diamine, and dodecamethylene diamine are preferable, and hexamethylene diamine is more preferable.

The lower limit of the component ratio of the diamine is usually 0 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more, particularly preferably 20 mol% or more of the total diamine component. The upper limit is usually 90 mol% or less of the total diamine component, preferably 70 mol% or less, more preferably 60 mol% or less, and particularly preferably 40 mol% or less.
The soft segment preferably includes a polyether component. Examples of the polyether component include poly C2-6 alkylene glycols such as polyethylene glycol (PEG), polypropylene glycol (PPG), and polytetramethylene glycol (PTMG), and poly C2-4 alkylene glycols. Among these, the polyether block preferably contains polypropylene glycol (PPG) or polytetramethylene glycol (PTMG) from the viewpoint of low water absorption, and may contain both PPG and PTMG. These can use multiple components,
Examples of other components that may be included in the soft segment include dicarboxylic acid, tricarboxylic acid, and polyester.

The lower limit of the amount of the polyether component is usually 1 mol% or more, preferably 3 mol% or more, more preferably 5 mol% or more, and particularly preferably 10 mol% or more of the entire polyamide resin from the viewpoint of adhesiveness. From the viewpoint of electrical characteristics, the upper limit is usually 90 mol% or less, preferably 85 mol% or less, more preferably 80 mol% or less, and particularly preferably 70 mol% or less of the entire polyamide resin.

  Moreover, as a component amount of the polyether in the undercoat layer, from the viewpoint of adhesiveness, the lower limit is usually 1% by mass or more, preferably 3% by mass or more, more preferably 5% by mass or more in the undercoat layer, Especially preferably, it is 10 mass% or more. From the viewpoint of electrical characteristics, the upper limit is usually 50% by mass or less in the undercoat layer, preferably 45% by mass or less, more preferably 40% by mass or less, and particularly preferably 30% by mass or less.

The component amount in the polyamide resin is preferably in the following range. For example, a polyamide resin having an elastic deformation rate of 56.0% or more can be obtained by adjusting the total of all components to 100% by mass within the following range.
The lower limit of the amount of the polyether component is usually preferably 15% by mass or more and 30% by mass or more, more preferably 70% by mass or more. The upper limit is usually preferably 90% by mass or less and 80% by mass or less.

The component amounts of lactam and aminocarboxylic acid are total, and the lower limit is usually preferably 5% by mass or more and 10% by mass or more, and more preferably 20% by mass or more. The upper limit is usually preferably 50% by mass or less and 30% by mass or less.
The total amount of the tri- or dicarboxylic acid component is generally 0.5% by mass or more, preferably 1% by mass or more, and more preferably 2% by mass or more. The upper limit is usually preferably 20% by mass or less and 10% by mass or less.

The amino group concentration of the polyamide resin is not particularly limited, but the lower limit is usually 10 mmol / kg or more. From the viewpoint of adhesiveness, it is preferably 15 mmol / kg or more, more preferably 20 mmol / kg or more. The upper limit is usually 300 mmol / kg or less, preferably 280 mmol / kg or less, more preferably 250 mmol / kg or less from the viewpoint of electrical characteristics.

The carboxyl group concentration of the polyamide resin is not particularly limited, but the lower limit is usually 10 mmol / kg or more, high thermal stability, and preferably 15 mmol / kg or more, more preferably 20 mmol / kg or more from the viewpoint of long-term stability. It is. The upper limit is usually 300mm
From the viewpoint of electrical characteristics, it is preferably 280 mmol / kg or less, more preferably 250 mmol / kg or less.

The lower limit of the number average molecular weight of the polyamide resin is usually 5000 or more, preferably 6000 or more, more preferably 7000 or more, from the viewpoint of the uniformity of the thickness of the undercoat layer. The upper limit is usually 200000 or less, preferably 100000 or less, more preferably 70000 or less, from the viewpoint of the solubility of the resin in the solvent.
The number average molecular weight can be measured in terms of polymethyl methacrylate by gel permeation chromatography using HFIP (hexafluoroisopropanol) as a solvent.

  The amide bond content of the polyamide resin can be selected from the range of 100 units or less per the polyamide resin, and from the viewpoint of leak resistance, the lower limit is usually 30 units or more, from the viewpoints of heat weldability and compatibility. Preferably it is 40 units or more, more preferably 50 or more. The upper limit is usually 90 units or less, preferably 80 units or less, more preferably 70 units or less from the viewpoint of water absorption. The amide bond content can be calculated, for example, by dividing the number average molecular weight by the molecular weight of the repeating unit (1 unit).

The polyamide resin may be amorphous or may have crystallinity. The degree of crystallinity of the copolymerized polyamide resin is 20% or less, preferably 10% or less. The crystallinity can be measured by a conventional method, for example, a measurement method based on density or heat of fusion, an X-ray diffraction method, an infrared absorption method, or the like.
The lower limit of the melting point or softening point of the polyamide resin is usually 75 ° C. or higher, preferably 90 ° C. or higher, more preferably 100 ° C. or higher from the viewpoint of the minimum drying temperature of the electrophotographic photosensitive member. The upper limit is usually 160 ° C. or lower, preferably 140 ° C. or lower, more preferably 130 ° C. or lower from the viewpoint of the maximum drying temperature of the electrophotographic photosensitive member. The melting point of the polyamide resin means a temperature corresponding to a single peak when each component is compatible and a single peak is generated by a differential scanning calorimeter (DSC). When each component is incompatible and a plurality of peaks are generated by DSC, the temperature corresponding to the peak on the high temperature side among the plurality of peaks means the melting point of the polyamide resin. The heat melting property can be measured as a softening temperature by a differential scanning calorimeter, and the melting point of the crystalline polyamide resin can be measured by a differential scanning calorimeter.

  There is no restriction | limiting in particular as a manufacturing method of the said polyamide resin, Although well-known methods as disclosed by Unexamined-Japanese-Patent No. 2010-222396 and Unexamined-Japanese-Patent No. 9-230673 can be used, For example, aminocarboxylic acid and dicarboxylic acid Is synthesized by stirring and polymerizing under a nitrogen atmosphere to synthesize a polyamide oligomer, and the oligomer is charged with a polyether, a catalyst and an antioxidant, and the polymer is stirred and heated in a nitrogen atmosphere while polymerizing. Can be obtained.

<Binder resin used for undercoat layer>
The undercoat layer is preferably formed in a form in which the metal oxide particles are dispersed in a binder resin. The binder resin used for the undercoat layer is epoxy resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, polyurethane resin, polyimide resin, chloride resin. Vinylidene 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, cellulose such as nitrocellulose Ester resin, cellulose ether resin, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, zirconium chelate compound, zirconi Organic zirconium compounds of the arm alkoxide compounds, titanyl chelate compounds, organic titanyl compounds such as titanyl alkoxide compound, may be a known binder resin such as a silane coupling agent. These can be used in a cured form together with a curing agent.

<Solvent used for coating solution for forming undercoat layer>
Any organic solvent that can dissolve the binder resin according to the present invention can be used as the organic solvent used in the coating solution for forming the undercoat layer. Specifically, alcohols having 5 or less carbon atoms such as methanol, ethanol, isopropyl alcohol, or normal propyl alcohol; halogens such as chloroform, 1,2-dichloroethane, dichloromethane, trichrene, carbon tetrachloride, 1,2-dichloropropane, etc. Hydrocarbons; Nitrogen-containing organic solvents such as dimethylformamide; Aromatic hydrocarbons such as toluene and xylene, and the like. Among these, any combination and a mixed solvent in any ratio can be used. Moreover, even if it is an organic solvent that does not dissolve the binder resin for the undercoat layer according to the present invention alone, it can be used as long as the binder resin can be dissolved, for example, by using a mixed solvent with the above organic solvent. can do. In general, coating unevenness can be reduced by using a mixed solvent.

<Dispersion method of coating liquid for forming undercoat layer>
The coating solution for forming the undercoat layer of the present invention preferably contains metal oxide particles, but the metal oxide particles are dispersed in the coating solution. In order to disperse the metal oxide particles in the coating liquid, for example, it can be produced by wet dispersion in an organic solvent with a known mechanical grinding device such as a ball mill, a sand grind mill, a planetary mill, or a roll mill. However, it is preferable to disperse using a dispersion medium. As the dispersion medium, a dispersion medium having an average particle size of usually 5 μm or more, preferably 10 μm or more, and usually 1 mm or less, preferably 500 μm or less, more preferably 200 μm or less, particularly preferably 100 μm or less is used. The mill may be either a vertical type or a horizontal type. The disc shape of the mill can be any plate type, vertical pin type, horizontal pin type or the like. Preferably, a liquid circulation type sand mill is used. As the wet stirring ball mill, for example, an ultra apex mill manufactured by Kotobuki Industries Co., Ltd. is preferably used.

  As the dispersion state, the undercoat layer was measured by a dynamic light scattering method of the secondary particles of the aggregate of the metal oxide in a liquid in which methanol and 1-propanol were mixed in a solvent mixed at a weight ratio of 7: 3. Preferably, the volume average particle size is 0.1 μm or less and the 90% cumulative particle size is 0.3 μm or less.

<Photosensitive layer>
The photosensitive layer is formed on the undercoat layer described above. As a type of the photosensitive layer, a charge generation material and a charge transport material (including the charge transport material of the present invention) are present in the same layer, and they are dispersed in a binder resin (hereinafter, appropriately, A single-layer photosensitive layer), and a charge generation layer in which a charge generation material is dispersed in a binder resin and a charge transport layer in which a charge transport material is dispersed in a binder resin. A function-separated type having a laminated structure (hereinafter referred to as “laminated photosensitive layer” as appropriate) may be mentioned, but any form may be employed.
In addition, as the laminated photosensitive layer, a charge-generating layer and a charge transport layer are laminated in this order from the conductive support side, and conversely, a charge transport layer and a charge generation layer are formed from the conductive support side. There are reverse laminated photosensitive layers provided in order, and any of them can be adopted, but a forward laminated photosensitive layer that can exhibit the most balanced photoconductivity is preferable.

<Functional separation type photosensitive layer>
<Charge generation layer>
The charge generation layer of the laminated photosensitive layer (function-separated type photosensitive layer) contains a charge generation material, and usually contains a binder resin and other components used as necessary. Such a charge generation layer is prepared by, for example, preparing a coating solution by dissolving or dispersing fine particles of a charge generation material and a binder resin in a solvent or a dispersion medium. It can be obtained by coating and drying on the top (on the undercoat layer when an undercoat layer is provided) and on the charge transport layer in the case of a reverse laminated type photosensitive layer.

<Charge generating material>
The charge generating material may be used alone or in a mixed state with several dyes and pigments.
Examples of the charge generating material include inorganic photoconductive materials such as selenium and its alloys, cadmium sulfide, and organic photoconductive materials such as organic pigments. Organic photoconductive materials are preferred, and organic photoconductive materials are particularly preferable. Pigments are preferred. Examples of organic pigments include phthalocyanine pigments, azo pigments, dithioketopyrrolopyrrole pigments, squalene (squarylium) pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, and benzimidazole pigments. . Among these, phthalocyanine pigments or azo pigments are particularly preferable as dyes used in the mixed state from the viewpoint of photosensitivity. When organic pigments are used as the charge generating substance, usually, fine particles of these organic pigments are used in the form of a dispersion layer bound with various binder resins.

  When a phthalocyanine pigment is used as the charge generation material, specifically, metal-free phthalocyanine and metal-containing phthalocyanine are used. Specific examples of metal-containing phthalocyanines include metals such as copper, indium, gallium, tin, titanium, zinc, vanadium, silicone, germanium, or their oxides, halides, hydroxides, alkoxides, and the like. Various crystal forms of phthalocyanines are used. In particular, titanyl phthalocyanines (also known as oxytitanium phthalocyanine) such as A type (also known as β type), B type (also known as α type), D type (also known as Y type), vanadyl phthalocyanine, chloroindium phthalocyanine, which are highly sensitive crystal types Chlorogallium phthalocyanine such as type II, hydroxygallium phthalocyanine such as type V, μ-oxo-gallium phthalocyanine dimer such as type G and I, and μ-oxo-aluminum phthalocyanine dimer such as type II are suitable. is there.

  Among these phthalocyanines, A type (β type), B type (α type), D type (Y type) oxytitanium phthalocyanine, II type chlorogallium phthalocyanine, V type hydroxygallium phthalocyanine, G type μ-oxo- Gallium phthalocyanine dimer and the like are particularly preferable. In particular, oxytitanium phthalocyanine preferably has a clear diffraction peak mainly at a Bragg angle (2θ ± 0.2 °) of 27.2 ° in a powder X-ray diffraction spectrum by CuKα characteristic X-ray.

Further, the oxytitanium phthalocyanine preferably has a clear diffraction peak at a Bragg angle (2θ ± 0.2 °) of 9.0 ° to 9.7 ° in a powder X-ray diffraction spectrum by CuKα characteristic X-ray. In view of the characteristics of the electrophotographic photosensitive member, main diffraction peaks at 9.6 °, 24.1 °, 27.2 °, or 9.5 °, 9.7 °, 24.1 °, and 27.2 ° are obtained. From the viewpoint of stability at the time of dispersion, it preferably has no peak at around 26.2 °. Among the oxytitanium phthalocyanines mentioned above, 7.3 °, 9.6 °, 11.6 °, 14.2 °, 18.0 °, 24.1 ° and 27.2 °, or 7.3 °, More preferably, it has main diffraction peaks at 9.5 °, 9.7 °, 11.6 °, 14.2 °, 18.0 °, 24.2 ° and 27.2 °.

  When a metal-free phthalocyanine compound or a metal-containing phthalocyanine compound is used as the charge generation material, a highly sensitive photoreceptor can be obtained with respect to a laser beam having a relatively long wavelength, for example, a laser beam having a wavelength around 780 nm. Further, when an azo pigment such as monoazo, diazo, or trisazo is used, white light, laser light having a wavelength around 660 nm, or laser light having a relatively short wavelength (for example, a wavelength in the range of 380 nm to 500 nm). It is possible to obtain a photoreceptor having sufficient sensitivity to the laser beam).

  The phthalocyanine compound may be a single compound or several mixed or mixed crystal states. As the mixed state in the phthalocyanine compound or crystal state here, those obtained by mixing the respective constituent elements later may be used, or the mixed state in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, crystallization, etc. It may be the one that gave rise to. 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 a charge generation material, various known azo pigments can be used as long as they have sensitivity to a light source for light input. Trisazo pigments are preferably used. Examples of preferred azo pigments are shown below.

  When the organic pigments exemplified above are used as the charge generation material, one kind may be used alone, or two or more kinds of pigments may be mixed and used. In this case, it is preferable to use a combination of two or more kinds of charge generating materials having spectral sensitivity characteristics in different spectral regions of the visible region and the near red region. Among them, a disazo pigment, a trisazo pigment and a phthalocyanine pigment are preferably used in combination. More preferred.

Examples of the binder resin used for the charge generation layer in the function-separated photoreceptor include polyvinyl butyral resin, polyvinyl formal resin, partially acetalized polyvinyl butyral resin in which a part of butyral is modified with formal, acetal, etc. Polyvinyl acetal resin, polyarylate resin, polycarbonate resin, polyester resin, modified ether polyester resin, phenoxy resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, polystyrene resin, acrylic resin, methacrylic resin, polyacrylamide Resin, polyamide resin, polyvinyl pyridine resin, cellulose resin, polyurethane resin, epoxy resin, silicone resin, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, casein, chloride Vinyl chloride-vinyl acetate, such as nyl-vinyl acetate copolymer, hydroxy-modified vinyl chloride-vinyl acetate copolymer, carboxyl-modified vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer Copolymers, styrene-butadiene copolymers, vinylidene chloride-acrylonitrile copolymers, styrene-alkyd resins, silicon-alkyd resins, insulating resins such as phenol-formaldehyde resins, poly-N-vinylcarbazole, polyvinylanthracene, It can be selected from organic photoconductive polymers such as polyvinyl perylene, but is not limited to these polymers. These binder resins may be used alone or in combination of two or more.

Specifically, the charge generation layer in the function-separated type photoconductor is prepared by dispersing a charge generation material by dispersing the above-mentioned binder resin in an organic solvent and then applying the coating solution on the conductive support (with an undercoat layer). If provided, it is formed by coating (on the undercoat layer).
Solvents used for the preparation of coating solutions and dispersion media for dissolving the binder resin include, for example, saturated aliphatic solvents such as pentane, hexane, octane and nonane, aromatic solvents such as toluene, xylene and anisole, chlorobenzene, Halogenated aromatic solvents such as dichlorobenzene and chloronaphthalene, amide solvents such as dimethylformamide and N-methyl-2-pyrrolidone, alcohol solvents such as methanol, ethanol, isopropanol, n-butanol and benzyl alcohol, glycerin, Aliphatic polyhydric alcohols such as polyethylene glycol, chain solvents such as acetone, cyclohexanone, methyl ethyl ketone, and cyclic ketone solvents, ester solvents such as methyl formate, ethyl acetate, n-butyl acetate, methylene chloride, chloroform, 1, 2-Dichro Halogenated hydrocarbon solvents such as ethane, linear ether solvents such as diethyl ether, dimethoxyethane, tetrahydrofuran, 1,4-dioxane, methylcellosolve, ethylcellosolve, acetonitrile, dimethylsulfoxide, sulfolane, hexa Examples include aprotic polar solvents such as methylphosphoric triamide, n-butylamine, isopropanolamine, diethylamine, triethanolamine, nitrogen-containing compounds such as ethylenediamine, triethylenediamine, and triethylamine, mineral oil such as ligroin, water, etc. Those which do not dissolve the undercoat layer are preferably used. These can be used alone or in combination of two or more.

In the charge generation layer of the function-separated type photoreceptor, the compounding ratio (mass) of the binder resin and the charge generation material is 10 to 1000 parts by weight, preferably 30 to 500 parts by weight with respect to 100 parts by weight of the binder resin. The film thickness is usually 0.1 μm to 10 μm, preferably 0.15 μm to 0.6 μm. If the ratio of the charge generation material is too high, the stability of the coating solution may be reduced due to aggregation of the charge generation material. On the other hand, if the ratio of the charge generating substance is too low, the sensitivity as a photoreceptor may be reduced.
As a method for dispersing the charge generation material, a known dispersion method such as a ball mill dispersion method, an attritor dispersion method, or a sand mill dispersion method can be used. In this case, it is effective to refine the particles to a particle size of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less.

<Charge transport layer>
<Binder resin>
In forming a charge transport layer of a function-separated type photoreceptor having a charge generation layer and a charge transport layer and a photosensitive layer of a single layer type photoreceptor, a binder resin is used to ensure film strength. In the case of the charge transport layer of the functional separation type photoconductor, a coating solution obtained by dissolving or dispersing the charge transport material and various binder resins in a solvent, or in the case of a single layer type photoconductor, the charge generation material and the charge transport It can be obtained by applying and drying a coating solution obtained by dissolving or dispersing the substance and various binder resins in a solvent. Examples of the binder resin include polymers and copolymers of vinyl compounds such as butadiene resin, styrene resin, vinyl acetate resin, vinyl chloride resin, acrylic ester resin, methacrylic ester resin, vinyl alcohol resin, ethyl vinyl ether, and polyvinyl butyral. Resin, polyvinyl formal resin, partially modified polyvinyl acetal, polycarbonate resin, polyester resin, polyarylate resin, polyamide resin, polyurethane resin, cellulose ester resin, phenoxy resin, silicone resin, silicon-alkyd resin, poly-N-vinylcarbazole resin, etc. Can be given. These resins may be modified with a silicon reagent or the like. Of the binder resins, polycarbonate resins and polyarylate resins are particularly preferable.

  These can also be used by crosslinking with an appropriate curing agent by heat, light or the like. Also, two or more kinds of binder resins can be blended and used. The viscosity average molecular weight of the polycarbonate resin and the polyarylate resin is not particularly limited, but is usually 10,000 or more, preferably 15,000 or more, more preferably 20,000 or more, provided that it is usually 300,000 or less. Preferably it is 200,000 or less, More preferably, it is 100,000 or less. If the viscosity average molecular weight is excessively small, the mechanical strength of the photosensitive layer is lowered, which is not practical. On the other hand, if the viscosity average molecular weight is excessively large, it is difficult to apply and form the photosensitive layer to an appropriate film thickness.

<Polycarbonate resin>
Next, the polycarbonate resin will be described. In general, polycarbonate resin is produced by a solvent method such as interfacial method (interfacial polycondensation method) or solution method in which bisphenols and phosgene are reacted in solution, or transesterification reaction between bisphenol and carbonic acid diester. A melting method in which a polycondensation reaction is carried out by using a method is widely used as an inexpensive production method. As the bisphenols, the following compounds are preferably used. As the polycarbonate resin, not only a homopolymer composed of one kind of bisphenols but also a copolymer produced by copolymerizing two or more kinds of bisphenols can be used.

  Among the above, a polycarbonate having a structural unit represented by the following formula (B) is preferable.

(In the general formula (B), the substituents R ^a and R ^b each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the substituents may be bonded to form a ring. R ^c and R ^d each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, j and k each represents 0 to 4. W represents a single bond, an oxygen atom, —CReRf—, The substituents R ^e and R ^f each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group, provided that the units of t and u have different structures.

  The carbon number of the alkyl group is usually 6 or less, preferably 4 or less, and particularly preferably 3 or less. Specific examples of the alkyl group include linear alkyl groups such as methyl, ethyl, and propyl groups, branched alkyl groups such as isopropyl, tertbutyl, and isobutyl groups, and cyclic groups such as cyclohexyl and cyclopentyl groups. An alkyl group can be mentioned, and among these, a methyl group is particularly preferable from the viewpoint of synthesis. Further, the substituents may be bonded to each other to form a ring.

The number of carbon atoms of the aryl group is usually 30 or less, preferably 20 or less, and more preferably 15 or less. Specific examples include a phenyl group, a naphthyl group, an anthranyl group, and a pyrenyl group. A phenyl group or a naphthyl group is preferable from the viewpoint of synthesis, and a naphthyl group is particularly preferable from the viewpoint of crack resistance. From this viewpoint, a phenyl group is particularly preferable.
Polycarbonate resins, especially those that have biphenyl as a partial structure and have a large content, for example, more than 30%, are restricted in use on electrophotographic photoreceptors due to poor adhesion. However, it can be used without any problem within the scope of the present invention.

<Polyarylate resin>
Examples of polyarylate resins that can be used in the present invention are shown below. This illustration is made for the purpose of clarifying the gist of the present invention, and is not limited to the illustrated structure unless it is contrary to the gist of the present invention.
The polyarylate resin contained in the photosensitive layer contains, for example, a repeating structure represented by the following general formula [1], and is produced by a known method, for example, with a divalent hydroxyaryl component and a dicarboxylic acid component. Can do.

In the general formula [1], Ar ^{1 to} Ar ⁴ may be the same or different, and each independently represents an arylene group which may have a substituent. The arylene group is not particularly limited, but an arylene group having 6 to 20 carbon atoms is preferable, and examples thereof include a phenylene group, a naphthylene group, an anthrylene group, a phenanthrylene group, and a pyrenylene group. Among these, a phenylene group and a naphthylene group are particularly preferable from the viewpoint of production cost. Further, when a phenylene group and a naphthylene group are compared, a phenylene group is more preferable in terms of ease of synthesis in addition to manufacturing cost. However, in the formula [1], when k = 0, when Ar ³ and Ar ⁴ are simultaneously unsubstituted arylene groups, the adhesive property of the photosensitive layer is poor, so either one of Ar ³ and Ar ⁴ is An arylene group having a substituent.

The substituent that may be independently present in the arylene group is not particularly limited, and preferred examples include a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, a condensed polycyclic group, and a halogen group. Considering the mechanical properties as the binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, the aryl group is preferably a phenyl group or a naphthyl group, and the halogen group is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. The alkoxy group is preferably a methoxy group, an ethoxy group, or a butoxy group. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and 1 to 2 carbon atoms. Are particularly preferable, and specifically, a methyl group is most preferable. The number of substituents for each of Ar1 to Ar4 is not particularly limited, but is preferably 3 or less, more preferably 2 or less, and particularly preferably 1 or less.

Further, in the general formula [1], Ar ¹ and Ar ² are preferably the same arylene group having the same substituent, and particularly preferably an unsubstituted phenylene group. Ar ³ and Ar ⁴ are preferably the same arylene group, and particularly preferably a phenylene group having a methyl group.
In General Formula [1], X represents a divalent organic residue having a single bond, an oxygen atom, a sulfur atom, a structure represented by Formula [2], or a structure represented by Formula [3]. R1 and R2 in the formula [2] each independently represent a hydrogen atom, an alkyl group, or aryl group, or a cycloalkylidene group and R ¹ and R ² are formed by bonding. Examples of the alkyl group of R ¹ and R ² in the formula [2] include a methyl group, an ethyl group, a propyl group, and a butyl group, and examples of the aryl group include a phenyl group and a naphthyl group. In addition, examples of the cycloalkylidene group formed by combining R ¹ and R ² in the formula [2] include a cyclopentylidene group, a cyclohexylidene group, and a cycloheptylidene group. Furthermore, R3 in Formula [3] represents an alkylene group, an arylene group, or a group represented by Formula [4]. Examples of the alkylene group represented by R ³ in the formula [3] include a methylene group, an ethylene group, and a propylene group. Examples of the arylene group represented by R ³ in the formula [3] include a phenylene group and a terphenylene group. Examples of the group represented by the formula [4] include a group represented by the following formula [5]. Among these, X is preferably an oxygen atom from the viewpoint of wear resistance.

In general formula [1], k is an integer of 0 to 5, preferably an integer of 0 to 1, and most preferably 1 from the viewpoint of wear resistance.
In general formula [1], Y represents a single bond, a sulfur atom, an oxygen atom, or a divalent organic residue having a structure represented by formula [6]. R6 and R7 in the formula [6] each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a cycloalkylidene group formed by combining R6 and R7. Considering the mechanical properties as the binder resin for the photosensitive layer and the solubility in the coating solution for forming the photosensitive layer, the aryl group is preferably a phenyl group or a naphthyl group, and the alkoxy group is preferably a methoxy group, an ethoxy group, or a butoxy group. preferable. Moreover, as an alkyl group, a C1-C10 alkyl group is preferable, More preferably, it is C1-C8, Most preferably, it is C1-2. Considering the simplicity of production of the divalent hydroxyaryl component used in producing the polyarylate resin, Y is a single bond, —O—, —S—, —CH ₂ —, —CH (CH ₃ ) —. , —C (CH ₃ ) ₂ — and cyclohexylidene are preferable, and —CH ₂ —, —CH (CH ₃ ) —, —C (CH ₃ ) ₂ — and cyclohexylidene are particularly preferable. Is —CH ₂ —, —CH (CH ₃ ) —.

In the present invention, the polyarylate resin is preferably a polyarylate resin having a repeating structure represented by the following general formula [7]. In the following general formula [7], Ar ^{16 to} Ar ¹⁹ each independently represent an arylene group which may have a substituent, and R ⁸ represents a hydrogen atom or an alkyl group.

In the general formula [7], Ar ^{16 to} Ar ¹⁹ respectively correspond to the Ar ^{1 to} Ar ⁴ and particularly preferably a phenylene group which may have a substituent. Moreover, as a preferable substituent, it is a hydrogen atom or an alkyl group, Most preferably, it is a methyl group. Further, in the general formula [7], Ar ¹⁸ and Ar ¹⁹ are the same phenylene group having a methyl group, and Ar ¹⁶ and Ar ¹⁷ are particularly preferably phenylene groups having no substituent. R8 represents a hydrogen atom or an alkyl group, and the alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably a methyl group.
The divalent hydroxyaryl component to be a divalent hydroxyaryl residue in the polyarylate resin is represented by the following general formula [8], but is preferably represented by the following general formula [9].

Ar ³ , Ar ⁴ and Y in the general formula [8] are as described above.

Ar ¹⁸ and Ar ¹⁹ in the general formula [9] independently represent a phenylene group which may have a substituent, and R ⁸ represents a hydrogen atom or a methyl group.
Specifically, when R ⁸ in the general formula [9] is a hydrogen atom, bis (2-hydroxyphenyl) methane, (2-hydroxyphenyl) (3-hydroxyphenyl) methane, (2-hydroxyphenyl) ( 4-hydroxyphenyl) methane, bis (3-hydroxyphenyl) methane, (3-hydroxyphenyl) (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) methane, bis (2-hydroxy-3-methylphenyl) Methane, bis (2-hydroxy-3-ethylphenyl) methane, (2-hydroxy-3-methylphenyl) (3-hydroxy-4-methylphenyl) methane, (2-hydroxy-3-ethylphenyl) (3- Hydroxy-4-ethylphenyl) methane, (2-hydroxy-3-methylphenyl) (4-hydroxy -3-methylphenyl) methane, (2-hydroxy-3-ethylphenyl) (4-hydroxy-3-ethylphenyl) methane, bis (3-hydroxy-4-methylphenyl) methane, bis (3-hydroxy-4) -Ethylphenyl) methane, (3-hydroxy-4-methylphenyl) (4-hydroxy-3-methylphenyl) methane, (3-hydroxy-4-ethylphenyl) (4-hydroxy-3-ethylphenyl) methane, Examples include bis (4-hydroxy-3-methylphenyl) methane and bis (4-hydroxy-3-ethylphenyl) methane. When R ⁸ is a methyl group, 1,1-bis (2-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) -1- (3-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) ) -1- (4-hydroxyphenyl) ethane, 1,1-bis (3-hydroxyphenyl) ethane, 1- (3-hydroxyphenyl) -1- (4-hydroxyphenyl) ethane, 1,1-bis ( 4-hydroxyphenyl) ethane, 1,1-bis (2-hydroxy-3-methylphenyl) ethane, 1,1-bis (2-hydroxy-3-ethylphenyl) ethane, 1- (2-hydroxy-3-) Methylphenyl) -1- (3-hydroxy-4-methylphenyl) ethane, 1- (2-hydroxy-3-ethylphenyl) -1- (3-hydroxy-4-ethylphenyl) Enyl) ethane, 1- (2-hydroxy-3-methylphenyl) -1- (4-hydroxy-3-methylphenyl) ethane, 1- (2-hydroxy-3-ethylphenyl) -1- (4-hydroxy) -3-ethylphenyl) ethane, 1,1-bis (3-hydroxy-4-methylphenyl) ethane, 1,1-bis (3-hydroxy-4-ethylphenyl) ethane, 1- (3-hydroxy-4) -Methylphenyl) -1- (4-hydroxy-3-methylphenyl) ethane, 1- (3-hydroxy-4-ethylphenyl) -1- (4-hydroxy-3-ethylphenyl) ethane, 1,1- Bis (4-hydroxy-3-methylphenyl) ethane and 1,1-bis (4-hydroxy-3-ethylphenyl) ethane are mentioned.

Among these, when R ⁸ in the general formula [9] is a hydrogen atom, bis (4-hydroxyphenyl) methane and (2-hydroxyphenyl) are considered in consideration of the ease of production of the divalent hydroxyaryl component. ) (4-hydroxyphenyl) methane, bis (2-hydroxyphenyl) methane, bis (4-hydroxy-3-methylphenyl) methane, bis (4-hydroxy-3-ethylphenyl) methane are particularly preferred. A combination of a plurality of divalent hydroxyaryl components can also be used.

In addition, when R ⁸ in the general formula [9] is a methyl group, 1,1-bis (4-hydroxyphenyl) ethane, 1- (2-hydroxyphenyl) -1- (4-hydroxyphenyl) ethane 1,1-bis (2-hydroxyphenyl) ethane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, and 1,1-bis (4-hydroxy-3-ethylphenyl) ethane are particularly preferable. A combination of a plurality of these divalent hydroxyaryl components can also be used.

Although general formula [9] is contained in general formula [8], the compound of general formula [8] other than the illustration of the said general formula [9] is also demonstrated below.
Specific examples of the divalent hydroxyaryl component represented by the general formula [8] include 3, 3 ′, 5
, 5'-tetramethyl-4,4'-dihydroxybiphenyl, 2,4,3 ', 5'-tetramethyl-3,4'-dihydroxybiphenyl, 2,2', 4,4'-tetramethyl-3 , 3′-dihydroxybiphenyl, bis (4-hydroxy-3,5-dimethylphenyl) ether, (4-hydroxy-3,5-dimethylphenyl) (3-hydroxy-2,4-dimethylphenyl) ether, bis ( 3-hydroxy-2,4-dimethylphenyl) ether, bis (4-hydroxy-3,5-dimethylphenyl) methane, (4-hydroxy-3,5-dimethylphenyl) (3-hydroxy-2,4-dimethyl Phenyl) methane, bis (3-hydroxy-2,4-dimethylphenyl) methane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) ethane 1- (4-hydroxy-3,5-dimethylphenyl) -1- (3-hydroxy-2,4-dimethylphenyl) ethane, 1,1-bis (3-hydroxy-2,4-dimethylphenyl) ethane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2- (4-hydroxy-3,5-dimethylphenyl) -2- (3-hydroxy-2,4-dimethylphenyl) propane, 2,2-bis (3-hydroxy-2,4-dimethylphenyl) propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane, 1- (4-hydroxy-3,5-dimethyl) Phenyl) -1- (3-hydroxy-2,4-dimethylphenyl) cyclohexane, 1,1-bis (3-hydroxy-2,4-dimethylphenyl) cyclohexane Preferably, 3,3 ′, 5,5′-tetramethyl-4,4′-dihydroxybiphenyl, bis (4-hydroxy-3,5-dimethylphenyl) ether, bis (4-hydroxy-3) , 5-dimethylphenyl) methane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) ethane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,1- Bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane. Alternatively, bis (2-hydroxyphenyl) ether, (2-hydroxyphenyl) (3-hydroxyphenyl) ether, (2-hydroxyphenyl) (4-hydroxyphenyl) ether, bis (3-hydroxyphenyl) ether, (3 -Hydroxyphenyl) (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) ether, bis (2-hydroxy-3-methylphenyl) ether, bis (2-hydroxy-3-ethylphenyl) ether, (2- Hydroxy-3-methylphenyl) (3-hydroxy-4-methylphenyl) ether, (2-hydroxy-3-ethylphenyl) (3-hydroxy-4-ethylphenyl) ether, (2-hydroxy-3-methylphenyl) ) (4-Hydroxy-3-methylphenyl) Ether, (2-hydroxy-3-ethylphenyl) (4-hydroxy-3-ethylphenyl) ether, bis (3-hydroxy-4-methylphenyl) ether, bis (3-hydroxy-4-ethylphenyl) ether, (3-hydroxy-4-methylphenyl) (4-hydroxy-3-methylphenyl) ether, (3-hydroxy-4-ethylphenyl) (4-hydroxy-3-ethylphenyl) ether, bis (4-hydroxy- 3-methylphenyl) ether, bis (4-hydroxy-3-ethylphenyl) ether, bis (4-hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane, bis (2- Hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) ketone, bis (4-hydroxyphenyl) ether, bis (4-hydroxy -3-methylphenyl) methane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4- Hydroxy-3-methylphenyl) cyclohexane, bis (4-hydroxy-3-methylphenyl) ether, bis (4-hydroxy-3,5-dimethylphenyl) methane, 1,1-bis (4-hydroxy-3,5) -Dimethylphenyl) ethane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane, bis (4-hydroxy-2,3,5-trimethylphenyl) phenylmethane, 1,1-bis (4-hydroxy-2,3,5-trimethylphenyl) ) Phenylethane, bis (4-hydroxyphenyl) -1-phenylmethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) -1-phenylpropane Bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) methoxymethane, 1,1-bis (4-hydroxyphenyl) -1-methoxyethane, 1,1- Bis (4-hydroxyphenyl) -1-methoxypropane, bis (4-hydroxy Eniru) dimethoxymethane, and the like.

Among these, bis (4-hydroxy-3,5-dimethylphenyl) methane and 2,2-bis (4-hydroxy-3,5-dimethylphenyl) are considered in consideration of the ease of production of the divalent hydroxyaryl component. Propane, 1,1-bis (4-hydroxy-3,5-dimethylphenyl) cyclohexane, or bis (4-hydroxyphenyl) ether, (2-hydroxyphenyl) (4-hydroxyphenyl) ether, bis (2- Hydroxyphenyl) ether, bis (4-hydroxy-3-methylphenyl) ether, and bis (4-hydroxy-3-ethylphenyl) ether are particularly preferable, and a combination of a plurality of these divalent hydroxyaryl components can be used. is there.
The dicarboxylic acid component which is a dicarboxylic acid residue in the polyarylate resin is represented by the following general formula [10].

Ar ¹ , Ar ² , X, and k in the general formula [10] are as described above, and the dicarboxylic acid residues contained in the formula [10] are represented by the following general formulas [I] to [VI]. The structure is preferably exemplified by the following general formula [11].

Ar ¹⁶ and Ar ¹⁷ in the general formula [11] are also as described above, and are preferably phenylene groups which may have a substituent.
Specific examples of the preferred dicarboxylic acid residue include diphenyl ether-2,2′-dicarboxylic acid residue, diphenyl ether-2,3′-dicarboxylic acid residue, diphenyl ether-
Examples include 2,4′-dicarboxylic acid residue, diphenyl ether-3,3′-dicarboxylic acid residue, diphenyl ether-3,4′-dicarboxylic acid residue, diphenyl ether-4,4′-dicarboxylic acid residue. Among these, considering the simplicity of production of the dicarboxylic acid component, diphenyl ether-2,2′-dicarboxylic acid residue, diphenyl ether-2,4′-dicarboxylic acid residue, diphenyl ether-4,4′-dicarboxylic acid Residues are more preferred, and diphenyl ether-4,4′-dicarboxylic acid residues are particularly preferred.

The polyarylate resin may be a resin containing another dicarboxylic acid component and enclosing the general formula [1] in a part of the structure. Specific examples of other dicarboxylic acid residues include adipic acid residues, suberic acid residues, sebacic acid residues, phthalic acid residues, isophthalic acid residues, terephthalic acid residues, toluene-2,5-dicarboxylic acid Residue, p-xylene-2,5-dicarboxylic acid residue, pyridine-2,3-dicarboxylic acid residue, pyridine-2,4-dicarboxylic acid residue, pyridine-2,5-dicarboxylic acid residue, pyridine -2,6-dicarboxylic acid residue, pyridine-3,4-dicarboxylic acid residue, pyridine-3,5-dicarboxylic acid residue, naphthalene-1,4-dicarboxylic acid residue, naphthalene-2,3-dicarboxylic acid An acid residue, naphthalene-2,6-dicarboxylic acid residue, biphenyl-2,2′-dicarboxylic acid residue, biphenyl-4,4′-dicarboxylic acid residue, preferably adipic acid residue, Seba Acid residue, phthalic acid residue, isophthalic acid residue, terephthalic acid residue, naphthalene-1,4-dicarboxylic acid residue, naphthalene-2,6-dicarboxylic acid residue, biphenyl-2,2′-dicarboxylic acid Acid residue, biphenyl-
It is a 4,4′-dicarboxylic acid residue, particularly preferably an isophthalic acid residue or a terephthalic acid residue. A combination of a plurality of these dicarboxylic acid residues can also be used.

  In addition, when it has the dicarboxylic acid residue constituting the present invention and the other dicarboxylic acid residues described above, the dicarboxylic acid residue constituting the present invention is preferably 70% or more as the number of repeating units, 80% or more is more preferable, and 90% or more is particularly preferable. Most preferably, it has only the dicarboxylic acid residue constituting the present invention, that is, the case where the dicarboxylic acid residue constituting the present invention is 100% as the number of repeating units.

<Charge transport material>
The charge transport material is not particularly limited, and any material can be used. Examples of known charge transport materials include aromatic nitro compounds such as 2,4,7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, electron withdrawing materials such as quinone compounds such as diphenoquinone, and 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, butadiene derivatives, enamine derivatives, and a plurality of these compounds Examples thereof include electron-donating substances such as polymers in which seeds are bonded, or polymers having a group consisting 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. Any one of these charge transport materials may be used alone, or two or more thereof may be used in any combination.

Preferred specific examples of the charge transport material are shown below. In the following compounds, R may be the same or different. Specifically, a hydrogen atom, an alkyl group, an alkoxy group, a phenyl group, an arylalkyl and the like are preferable. Particularly preferred is a methyl group, an ethyl group or a benzyl group. N is an integer of 0 or more and 2 or less.
The following examples are specific examples of the charge transport material, and other charge transport materials are not limited to the following.

The ratio of the binder resin to the charge transporting material is usually 20 parts by mass or more with respect to 100 parts by mass of the binder resin in both the single layer type and the laminated type, and preferably 30 parts by mass or more from the viewpoint of reducing the residual potential. From the viewpoint of stability and charge mobility, 40 parts by mass is more preferable. On the other hand, from the viewpoint of thermal stability of the photosensitive layer, it is usually 150 parts by mass or less, preferably 120 parts by mass or less from the viewpoint of compatibility between the charge transport material and the binder resin, and from the viewpoint of printing durability. 100 mass parts or less are more preferable, and 80 mass parts or less are especially preferable from a viewpoint of scratch resistance.
In the case of a multilayer photoreceptor, 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 from the viewpoint of long life, image stability, and high resolution. , Preferably 45 μm or less, more preferably 30 μm or less.

<Single layer type photosensitive layer>
The single-layer type photosensitive layer is formed using a binder resin in the same manner as the charge transport layer of the function-separated type photoreceptor in addition to the charge generation material and the charge transport material. Specifically, a charge generation material, a charge transport material, and various binder resins are dissolved or dispersed in a solvent to prepare a coating solution, and on a conductive support (on the undercoat layer when an undercoat layer is provided). It can be obtained by coating and drying.
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. A charge generation material is further dispersed in a charge transport medium comprising these charge transport materials and a 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 necessary 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. The total amount of the layer-type photosensitive layer is usually 0.5% by mass or more, preferably 1% by mass or more, and usually 50% by mass or less, preferably 20% by mass or less.
In addition, the usage ratio of the binder resin and the charge generation material in the single-layer type photosensitive layer is such that the charge generation material is usually 0.1 parts by weight or more, preferably 1 part by weight or more, based on 100 parts by weight of the binder resin. It is 30 mass parts or less, Preferably it is set as the range of 10 mass parts or less.

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.
In addition, in both the multilayer type photoreceptor and the single layer type photoreceptor, the film forming property, flexibility, coating property, stain resistance, gas resistance, light resistance, etc. are improved for the photosensitive layer or each layer constituting the photosensitive layer. For the purpose, a known antioxidant, plasticizer, ultraviolet absorber, electron-withdrawing compound, leveling agent, visible light shielding agent and the like may be contained.

<Other functional layers>
In a laminated or single layer type photoreceptor, a protective layer is provided on the outermost layer for the purpose of preventing the photosensitive layer from being worn and preventing or reducing the deterioration of the photosensitive layer due to discharge substances generated from a charger or the like. May be. 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 used for the protective layer include aromatic amino compounds such as TPD (N, N′-diphenyl-N, N′-bis- (m-tolyl) benzidine), antimony oxide, indium oxide, tin oxide, and oxide. Metal oxides such as titanium, tin oxide-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. Also, a skeleton having a charge transporting ability such as a triphenylamine skeleton as described in JP-A-9-190004 and a copolymer of the above resin can be used.

The electrical resistance of the protective layer is usually in the range of 109 Ω · cm to 1014 Ω · cm. When the electric resistance is higher than the range, the residual potential is increased, resulting in an image with much fogging. On the other hand, when the electric resistance is lower than the range, the image is blurred and the resolution is reduced. Further, the protective layer must be configured so as not to substantially prevent transmission of light irradiated during image exposure.
Further, for the purpose of reducing the frictional resistance and wear on the surface of the photoconductor, and increasing the transfer efficiency of the toner from the photoconductor to the transfer belt and paper, etc., the surface layer is made of a fluorine resin, silicone resin, polyethylene resin, You may contain the particle | grains which consist of these resin, and the particle | grains of an inorganic compound. Alternatively, a layer containing these resins and particles may be newly formed as a surface layer.

<Method for forming each layer>
Each layer constituting the above-described photoreceptor is formed by dip coating, spray coating, nozzle coating, bar coating, roll coating, blade coating on a conductive support obtained by dissolving or dispersing a substance to be contained in a solvent. It is formed by repeating a coating / drying step sequentially for each layer by a known method such as coating.

  There are no particular restrictions on the solvent or dispersion medium used for the preparation of the coating solution, but specific examples include alcohols such as methanol, ethanol, propanol and 2-methoxyethanol, tetrahydrofuran, 1,4-dioxane, dimethoxyethane and the like. Ethers, esters such as methyl formate and ethyl acetate, acetone, methyl ethyl ketone, cyclohexanone, ketones such as 4-methoxy-4-methyl-2-pentanone, aromatic hydrocarbons such as benzene, toluene, xylene, dichloromethane, Chlorinated hydrocarbons such as chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, trichloroethylene, n-butylamine, isopropanolamine, Diethyl Min, 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.

The amount of the solvent or the dispersion medium used is not particularly limited, but considering the purpose of each layer and the properties of the selected solvent / dispersion medium, it is appropriately determined so that the physical properties such as the solid content concentration and viscosity of the coating liquid are within a desired range. It is preferable to adjust.
For example, in the case of a charge transport layer of a single layer type photoreceptor or a function separation type photoreceptor, the solid content concentration of the coating solution is usually 5% by mass or more, preferably 10% by mass or more, and usually 40% by mass or less. The range is preferably 35% by mass or less. In addition, the viscosity of the coating solution is usually 10 mPa · s or higher, preferably 50 mPa · s or higher, and usually 500 mPa · s or lower, preferably 400 mPa · s or lower, at the temperature during use.

  In the case of a charge generation layer of a multilayer photoreceptor, the solid content concentration of the coating solution is usually 0.1% by mass or more, preferably 1% by mass or more, and usually 15% by mass or less, preferably 10% by mass. % Or less. In addition, the viscosity of the coating solution is usually 0.01 mPa · s or higher, preferably 0.1 mPa · s or higher, and usually 20 mPa · s or lower, preferably 10 mPa · s or lower, at the temperature during use.

Each layer constituting these photoconductors is formed by applying the coating solution obtained by the above-described method on a support using a known coating method, repeating the coating and drying steps for each layer, and sequentially coating the layers. The Examples of the coating method include a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method, an air knife coating method, and a curtain coating method. Other known coating methods can also be used.
The coating solution is preferably dried by touching at room temperature, followed by heating or drying in a temperature range of usually 30 ° C. or more and 200 ° C. or less for 1 minute to 2 hours, while still or blowing. Further, the heating temperature may be constant, or heating may be performed while changing the temperature during drying.

<Cartridge, image forming apparatus>
Next, a drum cartridge and an image forming apparatus using the electrophotographic photosensitive member of the present invention will be described with reference to FIG.
In FIG. 2, reference numeral 1 denotes a drum-shaped photoconductor, which is rotationally driven in the direction of the arrow at a predetermined peripheral speed. The photosensitive member 1 is uniformly charged at a predetermined positive or negative potential on the surface thereof by the charging unit 2 during the rotation process, and then exposure for forming a latent image is performed by the image exposure unit in the exposure unit 3.

  The formed electrostatic latent image is then developed with toner by the developing means 4, and the toner developed image is sequentially transferred onto the transfer body (paper or the like) P fed from the paper feeding unit by the corona transfer means 5. . In FIG. 2, the developing unit 4 includes a developing tank 41, an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45, and is configured to store toner T inside the developing tank 41. . Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing unit 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 image-transferred transfer body is then sent to the fixing means 7 where the image is fixed and printed out of the apparatus. The fixing unit 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. 2 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 surface of the photoreceptor 1 after the image transfer is cleaned by the cleaning unit 6 to remove the transfer residual toner, and is neutralized by the neutralization unit for the next image formation.

  In using the electrophotographic photosensitive member of the present invention, as a charger, in addition to a corona charger such as corotron or scorotron, a direct charging means for charging a charged member by contacting a directly charged member to which a voltage is applied is provided. It may be used. Examples of the direct charging means include a contact charger such as a charging roller and a charging brush. As the direct charging means, any one that involves air discharge or injection charging that does not involve air discharge is possible. In addition, as a voltage applied at the time of charging, in the case of only a direct current voltage, an alternating current can be superimposed on a direct current.

For the exposure, a halogen lamp, a fluorescent lamp, a laser (semiconductor, He—Ne), LED, a photoreceptor internal exposure system, or the like is used. As a digital electrophotographic system, it is preferable to use a laser, an LED, an optical shutter array, or the like. . As the wavelength, in addition to 780 nm monochromatic light, it is possible to use monochromatic light in the 600 to 700 nm region and slightly shorter wavelength.
As the development process, a dry development method such as cascade development, one-component insulating toner development, one-component conductive toner development, two-component magnetic brush development, or the like is used.

  As the toner, in addition to the pulverized toner, chemical toners such as suspension granulation, suspension polymerization, and emulsion polymerization aggregation can be used. In particular, in the case of chemical toners, those having a small particle diameter of about 4 to 8 μm are used, and those having a shape close to a sphere, and those outside a potato-like sphere can also be used. The polymerized toner is excellent in charging uniformity and transferability, and is preferably used for high image quality.

For the transfer step, electrostatic transfer methods such as corona transfer, roller transfer, and belt transfer, pressure transfer methods, and adhesive transfer methods are used. For fixing, heat roller fixing, flash fixing, oven fixing, pressure fixing, IH fixing, belt fixing, IHF fixing, etc. are used. These fixing methods may be used alone or in combination with a plurality of fixing methods. May be.
For cleaning, brush cleaner, magnetic brush cleaner, electrostatic brush cleaner, magnetic roller cleaner, blade cleaner, etc. are used.

In many cases, the static elimination step is omitted, but when used, a fluorescent lamp, LED, or the like is used, and an exposure energy that is three times or more of the exposure light is often used as the intensity. In addition to these processes, a pre-exposure process and an auxiliary charging process may be included.
In the present invention, a plurality of components such as the drum-shaped photosensitive member 1, the charging unit 2, the developing unit 4 and the cleaning unit 6 are integrally combined as a drum cartridge, and the drum cartridge is copied. It may be configured to be detachable from the main body of an electrophotographic apparatus such as a machine or a laser beam printer. For example, at least one of the charging unit 2, the developing unit 4, and the cleaning unit 6 can be integrally supported together with the drum-shaped photoreceptor 1 to form a cartridge.

  Hereinafter, the present invention will be described in more detail with reference to Production Examples, Reference Examples, Examples and Comparative Examples. In addition, the following examples are shown in order to explain the present invention in detail, and the present invention is not limited to the following examples unless it is contrary to the gist thereof.

[Production Example 1]
In a 5 liter pressure vessel equipped with a stirrer, thermometer, torque meter, pressure gauge, nitrogen gas inlet, pressure adjusting device and polymer outlet, 12-aminododecanoic acid 400.0 g and adipic acid 100.0 g were charged. After sufficiently replacing the container with nitrogen, the container was gradually heated while supplying nitrogen gas at a flow rate of 500 mL / min. Stirring was performed at a speed of 50 rpm. The temperature was raised from room temperature to 240 ° C. over 3 hours, and polymerization was carried out at 230 ° C. for 4 hours to synthesize nylon 12 oligomers.

  To this oligomer, 1500.0 g of polytetramethylene glycol (manufactured by BASF, PolyTHF 1800), 2.0 g of tetrabutyl zirconate and 5.0 g of an antioxidant (Tominox 917) were charged. After sufficiently replacing the inside of the container with nitrogen, heating was performed gradually while supplying nitrogen gas at a flow rate of 500 mL / min. Stirring was performed at a speed of 50 rpm. The temperature was raised from room temperature to 210 ° C. over 3 hours, heated at 210 ° C. for 3 hours, then gradually reduced in pressure to 50 Pa over 1 hour, polymerized for 2 hours, and then increased over 30 minutes. The temperature and pressure were reduced, and polymerization was completed at 230 ° C. and about 30 Pa for 3 hours. Next, stirring was stopped, nitrogen gas was supplied into the polymerization layer, and the pressure was returned to normal pressure. Next, the melted colorless and transparent polymer was drawn out from the polymer outlet through a string, cooled with water, and pelletized to obtain about 1.56 kg of polyamide resin I pellets.

[Production Example 2]
In a 5-liter pressure vessel equipped with a stirrer, thermometer, torque meter, pressure gauge, nitrogen gas inlet, pressure regulator and polymer outlet, 12-aminododecanoic acid, 80.02 g, XYX type triblock polyetherdiamine ( XTJ-542 manufactured by HUNTSMAN, total amine: 1.95 meq / g) 1049.30 g, 150.68 g of adipic acid, 2.81 g of a 35.55 mass% aqueous solution of sodium hypophosphite, and an antioxidant (Tominox 917) ) 5.00 g was charged. After sufficiently replacing the inside of the container with nitrogen, heating was performed gradually while supplying nitrogen gas at a flow rate of 500 mL / min. Stirring was performed at a speed of 50 rpm. The temperature was raised from room temperature to 225 ° C. over 4 hours, and polymerization was carried out at 225 ° C. for 10 hours. Next, the stirring was stopped, and the colorless and transparent polymer in a molten state was drawn out from the polymer take-out port into a string shape, cooled with water, and pelletized to obtain about 1.68 kg of polyamide resin II pellets.

<Other polyamide resins used in Examples and Comparative Examples>
Polyamide resin III: TPAE32 manufactured by Fuji Kasei Co., Ltd. Polyamide resin IV: PA100 manufactured by Fuji Kasei Co., Ltd., Japanese Patent Application Laid-Open No. 2006-20
See No. 8474
Polyamide resin V: PA200 manufactured by Fuji Kasei Co., Ltd., Patent Document 5 JP 2006-20
See No. 8474
Polyamide resin VI: Tomide 394 manufactured by Fuji Kasei Co., Ltd. Polyamide resin VII: Patent Document 6 Japanese Patent Application Laid-Open No. 2011-170041 Copolyamide described in Examples
・ Polyamide resin VIII: FR101, manufactured by Lead City Co., Ltd., see Patent Document 7 JP-A-2006-189595
・ Polyamide resin IX: FR301, manufactured by Lead City Co., Ltd., see JP-A-2006-189595
The components of the polyamide resin used in this example or comparative example are shown below.

<Manufacture of polyamide resin coating film and measurement of elastic deformation rate>
A polyamide resin coating film for measuring the elastic deformation rate was prepared according to the following procedure.
That is, 1.5 g of polyamide resin and 8.5 g of a mixed solution of methanol / n-propanol / toluene = 5/1/4 were mixed and stirred while heating to dissolve the polyamide resin.
A polyamide coating film was formed on a 20 cm square, 5 mm thick glass plate using an applicator so that the film thickness after drying was 20 μm, followed by drying at 125 ° C. for 20 minutes.
For this coating film, the <polyamide tree indicated by <elastic deformation rate and universal hardness>

Measurement was performed under the measurement conditions of the grease coating film] to obtain a value of elastic deformation rate. The results are shown in Table-1.

<Measurement of viscosity of polyamide resin solution>
A polyamide resin solution for viscosity measurement was prepared according to the following procedure.
That is, 4.5 g of the polyamide resin to be measured, 42.75 g of methanol and 42.75 g of toluene were mixed, and the polyamide resin was dissolved by heating and stirring to prepare a 5 wt% polyamide solution. About this solution, after returning solution temperature to room temperature, the viscosity measurement was performed immediately using the rotational viscometer. The measurement was performed under the conditions of a measurement temperature of 25 ° C. and a measurement rotation speed of 20 rpm to 50 rpm. The results are shown in Table-1.

<Manufacture of photoconductor for adhesion test>
[Example 1]
In accordance with the following procedure, a photoreceptor sheet as one form of the electrophotographic photoreceptor was produced. First, 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 mass 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 introduced into a mixing kneader (“SMG300” manufactured by Kawata Co., Ltd.) and mixed at a high rotational speed of 34.5 m / sec. 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 polyamide resin I are stirred and mixed while heating to dissolve the polyamide resin, and then subjected to ultrasonic dispersion treatment to obtain methanol / 1. -Dispersion for undercoat layer having a solid content concentration of 18.0% containing a propanol / toluene mass ratio of 6/1/3 and a hydrophobically treated titanium oxide / polyamide resin I at a mass ratio of 3/1. .

The undercoat layer-forming coating solution thus obtained is applied onto a 0.5 mm thick aluminum plate with a wire bar so that the film thickness after drying is 1.5 μm, dried and subbed. A layer was provided. Next, 10 parts by mass of oxytitanium phthalocyanine having a powder X-ray diffraction spectrum shown in FIG. 3 is shown in which X-ray diffraction by CuKα ray shows a strong diffraction peak with a Bragg angle (2θ ± 0.2) of 27.3 °. In addition to 150 parts by mass of 2-dimethoxyethane, pulverization and dispersion treatment was performed with a sand grind mill to prepare a pigment dispersion. 160 parts by mass of the pigment dispersion thus obtained was added to 100 parts by mass of a 5% 1,2-dimethoxyethane solution of polyvinyl butyral (trade name # 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.), and an appropriate amount of 1,2 -Dimethoxyethane was added to finally prepare a coating solution for forming a charge generation layer having a solid content concentration of 4.0% by mass.

This charge generation layer forming coating solution was applied on the above-described undercoat layer with a wire bar so that the film thickness after drying was 0.4 μm, and then dried to form a charge generation layer.
Next, as a charge transport material, 30 mixture of geometric isomer compounds having a structure represented by the following formula [12] as a main component shown in Example 1 of JP-A-2002-80432 is disclosed. Part by mass, polyarylate A (PAR-A, viscosity average molecular weight 41
, 000) 100 parts by mass, and 0.05 parts by mass of silicone oil as a leveling agent are mixed with 640 parts by mass of a mixed solvent of tetrahydrofuran and toluene (tetrahydrofuran 80% by mass, toluene 20% by mass) to form a charge transport layer. A coating solution was prepared.

  This charge transport layer forming coating solution is applied onto the above-described charge generation layer using an applicator so that the film thickness after drying is 20 μm, and dried at 125 ° C. for 20 minutes to form a charge transport layer. Then, a photoconductor PE1 for adhesion test was produced.

<Adhesion test>
On this adhesive test photoreceptor, an NT cutter was used to cut 3 pieces vertically and 4 pieces horizontally at intervals of 5 mm to produce 2 × 3 6 squares. Cellotape (registered trademark) (manufactured by Nichiban Co., Ltd.) was applied from above, and the adhesion of the photosensitive layer was tested by pulling it up to 90 ° with respect to the adhesion surface. This was performed at five places, and the ratio of the number of squares of the photosensitive layer remaining on the support out of the total 30 squares was evaluated as the residual ratio. The larger the number of remaining masses, the higher the residual rate and the better the adhesiveness. The results are shown in Table-2.

[Example 2]
In place of 100 parts by mass of polyarylate B (PAR-B) having the following repeating structure instead of the binder resin polyarylate A (PAR-A) used in the charge transport layer forming coating solution of Example 1. In the same manner as in Example 1, a photoconductor PE2 for adhesion test was produced. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[Example 3]
Except that the binder resin polyarylate A (PAR-A) used in the coating liquid for forming the charge transport layer of Example 1 was replaced with 100 parts by mass of polycarbonate C (PCR-C) having the following repeating structure. In the same manner as in Example 1, a photoconductor PE3 for adhesion test was produced. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[Example 4]
Instead of the polyamide resin I used in the dispersion for the undercoat layer of Example 1, polyamide resin II
A photoconductor PE4 for adhesion test was produced in the same manner as in Example 1 except that was used. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.
[Example 5]
Example 4 except that 100 parts by mass of polyarylate B (PAR-B) was used instead of polyarylate A (PAR-A) as the binder resin used in the charge transport layer forming coating solution of Example 4. In the same manner, a photoconductor PE5 for adhesion test was produced. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[Example 6]
Example 4 except that 100 parts by mass of polycarbonate C (PCR-C) was used instead of polyarylate A (PAR-A) as the binder resin used in the coating solution for forming the charge transport layer of Example 4. Similarly, a photoconductor PE6 for adhesion test was produced. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[Example 7]
A photoconductor PE7 for adhesion test was prepared in the same manner as in Example 1 except that the polyamide resin III was used instead of the polyamide resin I used in the undercoat layer dispersion of Example 1. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.
[Example 8]
Example 7 except that 100 parts by mass of polyarylate B (PAR-B) was used instead of polyarylate A (PAR-A) as the binder resin used in the coating liquid for forming the charge transport layer of Example 7. In the same manner, a photoconductor PE8 for adhesion test was produced. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[Example 9]
Example 7 and Example 7 except that polycarbonate C (PCR-C) was used in an amount of 100 parts by mass instead of polyarylate A (PAR-A) as a binder resin used in the charge transport layer forming coating solution of Example 7. Similarly, a photoconductor PE9 for adhesion test was produced. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[Example 10]
Adhesiveness was the same as in Example 1 except that the undercoat layer coating solution prepared without using the hydrophobically treated titanium oxide in Example 1 was used instead of the undercoat layer dispersion of Example 1. Test photoconductor PE10 was produced. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[Example 11]
Example 1 except that the undercoat layer dispersion prepared by changing the mass ratio of the hydrophobically treated titanium oxide / polyamide resin I to 2/1 was used instead of the undercoat layer dispersion of Example 1. In the same manner, a photoconductor PE11 for adhesion test was produced. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[Example 12]
Example 1 except that the undercoat layer dispersion prepared by changing the mass ratio of hydrophobically treated titanium oxide / polyamide resin I to 4/1 was used instead of the undercoat layer dispersion of Example 1. In the same manner, a photoconductor PE12 for adhesion test was produced. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[Example 13]
Adhesion was carried out in the same manner as in Example 1 except that polyamide resin I and polyamide resin VII were blended at a mass ratio of 1/2 instead of polyamide resin I used in the undercoat layer dispersion of Example 1. A photoconductor PE13 for property test was prepared. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[Example 14]
A photoconductor PE14 for adhesion test was prepared in the same manner as in Example 1 except that aluminum oxide was used instead of the hydrophobically treated titanium oxide of Example 1. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.
[Comparative Example 1]
Instead of polyamide resin I used in the dispersion for the undercoat layer of Example 3, polyamide resin IV
A photoconductor PP1 for adhesion test was produced in the same manner as in Example 3 except that was used. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[Comparative Example 2]
A photoconductor PP2 for adhesion test was produced in the same manner as in Example 4 except that the polyamide resin V was used instead of the polyamide resin I used in the undercoat layer dispersion of Example 3. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.
[Comparative Example 3]
Instead of polyamide resin I used in the dispersion for the undercoat layer of Example 3, polyamide resin VI
A photoconductor PP3 for adhesion test was produced in the same manner as in Example 3 except that was used. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[Comparative Example 4]
Instead of the polyamide resin I used in the dispersion for the undercoat layer of Example 1, polyamide resin VII
A photoconductor PP4 for adhesion test was produced in the same manner as in Example 1 except that was used. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.
[Comparative Example 5]
A photoconductor PP5 for adhesion test was prepared in the same manner as in Example 2 except that the polyamide resin VII was used instead of the polyamide resin I used in the undercoat layer dispersion of Example 2. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[Comparative Example 6]
An adhesion test photoreceptor PP6 was prepared in the same manner as in Example 3 except that polyamide resin VII was used instead of polyamide resin I used in the undercoat layer dispersion of Example 3. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.
[Comparative Example 7]
An adhesive test photoreceptor PP7 was prepared in the same manner as in Example 3 except that polyamide resin VIII was used instead of polyamide resin I used in the undercoat layer dispersion of Example 3. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

[Comparative Example 8]
Instead of polyamide resin I used in the dispersion for the undercoat layer of Example 3, polyamide resin IX
A photoconductor PP8 for adhesion test was produced in the same manner as in Example 3 except that was used. This adhesion test photoreceptor was evaluated in the same manner as in Example 1, and the results are shown in Table 2.

  As can be seen from the results in Table 2, it can be seen that when a polyamide resin within the range of the parameters of the present invention is used for the undercoat layer, the adhesion is remarkably improved. It can also be seen that the polyamide resin having a higher elastic deformation rate improves the adhesion. As the content of the polyamide resin in the undercoat layer within the parameter range of the present invention is larger, the effect of improving the adhesiveness is increased.

<Photosensitive drum creation method>
[Production Example 3]
The coating solution for forming the undercoat layer used in Example 3 was applied to an aluminum cylinder having an outer diameter of 30 mm, a length of 260.5 mm, and a wall thickness of 0.75 mm. A coating layer was formed, and the coating solution for charge generation layer and the coating solution for charge transport layer used in Example 3 were sequentially coated on the undercoating layer by a dip coating method. A charge generation layer and a charge transport layer were formed so as to have a thickness of 4 μm and 18 μm, and a photosensitive drum DE1 was produced.

[Production Example 4]
Photosensitive drum DE2 was produced in the same manner as in Production Example 3, except that polyamide resin III was used instead of polyamide resin I used in the undercoat layer dispersion of Production Example 3.
[Production Example 5]
Photosensitive drum DP1 was produced in the same manner as in Production Example 3, except that polyamide resin V was used instead of polyamide resin I used in the undercoat layer dispersion of Production Example 3.
[Production Example 6]
Photoreceptor drum DP2 was produced in the same manner as in Production Example 3, except that polyamide resin VII was used instead of polyamide resin I used in the undercoat layer dispersion of Production Example 3.

[Reference example]
<Image characteristics test>
Using the photosensitive drums obtained in Production Examples 1 to 4, an image characteristic test was performed.
The image characteristic test was performed using a color printer HP Color LaserJet 4650dn (cleaning blade, counter contact method) manufactured by Hewlett-Packard Company.
The produced photosensitive drum and toner were mounted on a cyan process cartridge, and this cartridge was mounted on a printer. 10,000 images were formed under a temperature of 10 ° C. and a humidity of 15% (sometimes referred to as an LL environment), and ghosts, fogging, and density reduction were evaluated. The results are shown in Table-3.

“Image quality” item ◎: Image abnormality is not observed at all.
◯: Slightly observed ghost, poor density under LL environment, dirt on the background, etc., but good for practical use.
(Triangle | delta): Although a ghost, the density | concentration defect in LL environment, the stain | pollution | contamination of a background part, etc. are observed, it is a level which can be used practically.
X: Ghost, density defect under LL environment, dirt on background, etc. are obvious and have practical problems.

As shown in Table 3, it can be seen that the electrophotographic photosensitive member using the polyamide resin within the parameter range of the present invention exhibits good image characteristics.
[Production Example 7]
Photosensitive drum DP3 was produced in the same manner as in Production Example 3, except that polyamide resin VIII was used instead of polyamide resin I used in the undercoat layer dispersion of Production Example 3.

[Production Example 8]
Instead of the polyamide resin I used in the dispersion for the undercoat layer of Production Example 3, polyamide resin IX
A photosensitive drum DP4 was produced in the same manner as in Production Example 3 except that was used.
[Example 15]
<Universal hardness measurement of undercoat layer>
The photosensitive drum DE1 obtained in Production Example 3 was immersed in a tetrahydrofuran solution, and the photosensitive layer was peeled so that the undercoat layer became the outermost surface. After drying at 125 ° C. for 20 minutes, measurement was carried out under [Measurement conditions of undercoat layer] indicated by <elastic deformation rate and universal hardness> to obtain a value of universal hardness. The results are shown in Table-4.

[Example 16]
Universal hardness was measured in the same manner as in Example 15 for the photosensitive drum DE2 obtained in Production Example 4. The results are shown in Table-4.
[Comparative Example 9]
Universal hardness was measured in the same manner as in Example 15 for the photosensitive drum DP1 obtained in Production Example 5. The results are shown in Table-4.

[Comparative Example 10]
Universal hardness was measured in the same manner as in Example 15 for the photosensitive drum DP2 obtained in Production Example 6. The results are shown in Table-4.
[Comparative Example 11]
Universal hardness was measured in the same manner as in Example 15 for the photosensitive drum DP3 obtained in Production Example 7. The results are shown in Table-4.

[Comparative Example 12]
Universal hardness was measured in the same manner as in Example 15 for the photosensitive drum DP4 obtained in Production Example 8. The results are shown in Table-4.

As can be seen from the results of Table-2 and Table-4, it can be seen that when a polyamide resin within the parameter range of the present invention is used for the undercoat layer, it has good adhesiveness.
[Example 17]
A photoconductor in the same manner as in Example 15 except that an aluminum cylinder having an outer diameter of 30 mm, a length of 376 mm, and a wall thickness of 0.75 mm was used instead of the aluminum cylinder used in Example 15. Drum DE3 was produced.

[Comparative Example 13]
A photoconductor in the same manner as in Comparative Example 12 except that an aluminum cylinder having an outer diameter of 30 mm, a length of 376 mm, and a wall thickness of 0.75 mm was used instead of the aluminum cylinder used in Comparative Example 12. Drum DP5 was produced.
The photosensitive drums DE3 and DP5 produced here were mounted on a black drum cartridge for a color printer MICROLINE Pro 9800PS-E manufactured by Oki Data. Next, a developing toner (volume average particle size 7.05 μm, Dv / Dn = 1.14, average circularity 0. 10 μm) manufactured according to the manufacturing method (emulsion polymerization aggregation method) of developing toner A disclosed in Japanese Patent Application Laid-Open No. 2007-213050. 963) was mounted on a black toner cartridge. These drum cartridges and toner cartridges were mounted on the printer.
Specifications of MICROLINE Pro 9800PS-E
Quadruple tandem
Color 36ppm, Monochrome 40ppm
1200 dpi
Contact roller charging (DC voltage applied)
LED exposure
With static elimination light
30,000 images of a text document having a printing area of about 5% were formed under conditions of a temperature of 25 ° C. and a humidity of 50%. The results of the image characteristic test at that time are shown in Table-5.

As shown in Table 5, the electrophotographic photosensitive member DE3 of Example 17 within the parameter range of the present invention showed good image characteristics even after printing 30,000 sheets. However, Comparative Example 1
Photoreceptor drum DP5 No. 3 is considered to be caused by poor adhesion of the photosensitive layer, causing small scratches at the end of the drum, which causes smearing at the end of the image, and this is a problem in practical use. The result was.

  From the results of Table-1 to Table-5, it can be seen that the electrophotographic photosensitive member within the parameter range of the present invention has remarkably good adhesiveness. These photoreceptors also showed good image characteristics.

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

Claims (3)

An electrophotographic photosensitive member having at least an undercoat layer and a photosensitive layer on a conductive support, and comprising a polyamide resin having a universal hardness based on the following measurement method of the undercoat layer of 55 N / mm ² or less. , Electrophotographic photoreceptor.
[Measurement method]
Maximum when the undercoating layer is measured under the conditions of a temperature of 25 ° C. and a relative humidity of 50% using a Vickers indenter under conditions of a maximum indentation load of 0.2 mN, a load time of 10 seconds, and an unload time of 10 seconds. The value defined by the following formula from the indentation depth is the universal hardness.
Universal hardness (N / mm ² )
= Test load (N) / Surface flaw of Vickers indenter under test load (mm ² ) The electrophotographic photosensitive member according to claim 1 , 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 on the electrophotographic photosensitive member An electrophotographic photosensitive member cartridge comprising: a developing unit that develops the formed electrostatic latent image; and a cleaning unit that cleans the electrophotographic photosensitive member. The electrophotographic photosensitive member according to claim 1 , 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 the electrophotographic photosensitive member An image forming apparatus comprising: a developing unit that develops the electrostatic latent image formed on the image forming apparatus.

Images