JP2009175726A - Electrophotographic photoreceptor and method for manufacturing the same, electrophotographic cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an electrophotographic photoreceptor which uses a polyester resin as a binder resin of a photosensitive layer, exhibits little decrease in mechanical functions of the electrophotographic photoreceptor when repeatedly used, can continuously form favorable images similar to images in the initial stage of starting usage as well as can output sufficient image contrast with a small energy and has less image defects such as white spots and black dots. <P>SOLUTION: The method for manufacturing an electrophotographic photoreceptor having a photosensitive layer including a polyester-containing layer formed by applying a coating liquid containing a polyester resin on a conductive support, is characterized in that upon forming the polyester-containing layer, the coating film of the coating liquid is dried under a plurality of temperature conditions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member used for a copying machine, a printer, and the like, a manufacturing method thereof, an electrophotographic cartridge using the electrophotographic photosensitive member, and an image forming apparatus using the electrophotographic photosensitive member. More specifically, the present invention relates to a method for producing an electrophotographic photoreceptor using a polyester resin as a photosensitive layer, an electrophotographic cartridge using the electrophotographic photoreceptor produced by the production method, and an image forming apparatus.

  C. F. The electrophotographic technology according to Carlson's invention is used not only in the field of copiers, but also in the fields of various printers and facsimiles, because of its excellent immediacy, high quality and high storage stability. It is also widely used as a digital multi-function peripheral, and is expanding greatly. As for the electrophotographic photosensitive member which is the core of the electrophotographic technology, the photoconductive material is an organic photoconductive material having advantages such as non-pollution, easy film formation, and easy manufacture. Mainly used.

  In particular, since an electrophotographic photosensitive member (so-called function-separated type electrophotographic photosensitive member) in which functions such as generation and movement of charge carriers are assigned to different organic photoconductive substances is effective for high sensitivity, It has become mainstream in recent years. Several layer configurations have been devised for the photosensitive layer of such a function-separated electrophotographic photosensitive member. In particular, a charge generation layer and a charge transport layer are stacked to separate the functions of charge generation and charge transport, a so-called laminated photosensitive layer, and a so-called single layer containing a charge generation material and a charge transport material in the same layer. A layer-type photosensitive layer (see, for example, Patent Documents 1 to 5) is generally used. In particular, the multi-layer photosensitive layer can provide a highly sensitive electrophotographic photosensitive member, can provide a highly safe electrophotographic photosensitive member with a wide selection range of materials, and has high productivity and is advantageous in terms of cost. For these reasons, the electrophotographic photosensitive member is now mainstream and is produced in large quantities.

  Incidentally, in recent years, in the field of image formation, digitization is rapidly progressing in order to obtain a higher quality image, or to store an input image or freely edit it. In the past, digital image formation has been limited to laser printers, LED printers, and some color laser copiers that are output devices of word processors and personal computers. Digitization was almost completely achieved even in the field of general copying machines where mainstream image formation was the mainstream.

  When digital image formation is performed, laser light or LED light is mainly used as a light source for inputting a digital signal to the electrophotographic photosensitive member. Currently, near-infrared light having a wavelength of 780 nm and a wavelength of 660 nm and long-wavelength light close thereto are widely used as a transmission wavelength of a light source for light input that is widely used at present. In recent years, blue lasers have been put into practical use, and it has become possible to use short wavelength light having a wavelength of 400 to 500 nm as a light source for light input. As an electrophotographic photosensitive member used for digital image formation, it is necessary to have an effective sensitivity to these various light input light sources, and a wide variety of materials have been studied as a material for the photosensitive layer. .

  Also, if the photosensitive layer is damaged, such as rubbing against the cleaning blade, magnetic brush, etc., contact with the developer, paper, etc., the surface of the photosensitive layer may be scratched or worn, or the photosensitive layer may be peeled off. In this case, this portion tends to appear on an image formed as a defect, and the image quality is impaired. Therefore, the mechanical strength of the photosensitive layer is a major factor limiting the life of the electrophotographic photosensitive member, and it is also desired to increase the mechanical strength as well as the electrical and chemical durability.

  Here, in the organic electrophotographic photoreceptor, each layer is usually bound by a binder resin, and a binder resin can be mentioned as a factor that substantially determines the strength of each layer. In particular, in a photosensitive layer containing a binder resin and a charge transport material, it is difficult to provide sufficient mechanical strength because the doping amount of the charge transport material is considerably large. In recent years, therefore, much research has been conducted on polyester resins as binder resins for photosensitive layers. The polyester resin may have better mechanical properties than the polycarbonate resin, and there are cases where it is used in practice (for example, see Patent Document 6).

  In particular, when a polyester resin using a dihydric phenol component having a specific structure is used as the binder resin, the stability of the coating solution is improved, and further, the mechanical strength and wear resistance of the electrophotographic photosensitive member are improved. It has also been reported (see Patent Document 7 and Patent Document 8).

JP-A-61-77054 JP-A 61-188543 JP-A-2-228670 Japanese Examined Patent Publication No. 7-97223 Japanese Examined Patent Publication No. 7-97225 Japanese Patent Laid-Open No. 2003-140370 Japanese Patent Laid-Open No. 10-288845 Japanese Patent Laid-Open No. 10-288846

  However, when the polyester resin is used as the binder resin, the residual potential tends to be larger than when the polycarbonate resin is used as the binder resin. When an electrophotographic photosensitive member having a large residual potential is used, it is difficult to reproduce a contrast having a sufficient image density for the formed image. In addition, image defects such as white spots and black spots due to residual charges may occur. Further, a larger amount of energy may be required during image formation. Therefore, it may be difficult to use a polyester resin as a binder resin in terms of residual potential and the like.

  The present invention was devised in view of the background art described above, using a polyester resin as the binder resin of the photosensitive layer, and less in the mechanical function of the electrophotographic photosensitive member when repeatedly used. It is intended to obtain an electrophotographic photosensitive member that not only can continuously form a good image, but also can provide sufficient image contrast with a small amount of energy and has few image defects such as white spots and black spots. It is.

  As a result of intensive studies to solve the above problems, the present inventors have excellent mechanical strength by drying a coating film under specific conditions when a polyester resin is used as a binder resin for forming a photosensitive layer. The inventors have found that it is possible to form a photosensitive layer having a small residual potential, and have completed the present invention.

  A first gist of the present invention is a method for producing an electrophotographic photosensitive member having a photosensitive layer including a polyester-containing layer formed by applying a coating solution containing a polyester resin on a conductive support. The present invention resides in a method for producing an electrophotographic photoreceptor, wherein the coating film coated with the coating solution is dried under a plurality of temperature conditions.

（式（１）中、Ａｒ¹及びＡｒ²は置換基を有してもよいアリーレン基を表し、Ｘ¹及びＹ¹は２価の連結基を表す。） Under the present circumstances, it is preferable that the said polyester resin has a repeating structure represented by following formula (1) (Claim 2).

(In Formula (1), Ar ¹ and Ar ² represent an arylene group which may have a substituent, and X ¹ and Y ¹ represent a divalent linking group.)

  The second gist of the present invention resides in an electrophotographic photosensitive member produced by the above-described method for producing an electrophotographic photosensitive member (claim 3).

  The third gist of the present invention is an electrophotographic photosensitive member produced by any one of the above-described methods for producing an electrophotographic photosensitive member, charging means for charging the electrophotographic photosensitive member, and the charged electrophotographic photosensitive member. Image exposing means for performing image exposure to form an electrostatic latent image, developing means for developing the electrostatic latent image with toner, transfer means for transferring the toner to the transferred body, transferred to the transferred body An electrophotographic cartridge comprising at least one selected from a fixing unit for fixing the toner and a cleaning unit for collecting the toner adhering to the electrophotographic photosensitive member (claim 4).

  Further, the fourth aspect of the present invention is an electrophotographic photosensitive member produced by any one of the above-described methods for producing an electrophotographic photosensitive member, a charging means for charging the electrophotographic photosensitive member, and the charged electrophotographic member. An image exposure unit that exposes the photosensitive member to form an electrostatic latent image; a developing unit that develops the electrostatic latent image with toner; and a transfer unit that transfers the toner to a transfer target. The present invention resides in a characteristic image forming apparatus.

  According to the present invention, even when the electrophotographic photoreceptor is repeatedly used, the residual potential of the photosensitive layer can be reduced. That is, not only at the start of use, but also after repeated use and after receiving mechanical and electrical loads, the change in electrical characteristics is small, and an image can be formed with an optimal amount of toner ink. Further, image defects such as an increase or decrease in image density do not occur. Furthermore, the electrophotographic photosensitive member is less susceptible to physical damage such as scratches and cracks and has excellent durability.

  Therefore, since the electrophotographic photosensitive member produced according to the present invention has extremely good electrical characteristics and excellent durability, it can be suitably used for an image forming apparatus such as a high-speed copying machine or a color printer. .

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail below. However, the description of the constituent elements described below is a representative example of the embodiments of the present invention, and is appropriately modified without departing from the spirit of the present invention. can do.

A. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an electrophotographic photoreceptor having a photosensitive layer including a polyester-containing layer formed by applying a coating solution containing a polyester resin on a conductive support, and the production method thereof. The electrophotographic photosensitive member is characterized in that when the polyester-containing layer is formed, the coating film coated with the coating liquid is dried under a plurality of temperature conditions.

  The drying of the coating film under a plurality of temperature conditions in the present invention means that the coating film is allowed to stand at a certain temperature for a predetermined time or more in an atmosphere of two or more different temperature ranges to dry the coating film. Say. In the present invention, since the coating film is dried under a plurality of temperature conditions, the physical resistance of the photosensitive layer including the polyester-containing layer is made favorable, and further after being subjected to a mechanical load and an electrical load. The change in electrical characteristics can be small (the residual potential is small). Therefore, even when the electrophotographic photosensitive member is used repeatedly, the increase or decrease of the image density is small, and the formed image can have few defects. The reason is not clear, but the following is expected.

  The coating solution for forming the polyester-containing layer usually contains a solvent. In the present invention, the coating solution is divided into two or more stages including a relatively high temperature condition and a relatively low temperature condition. Control the evaporation speed of the solvent. For example, under relatively low temperature conditions, the solvent can be volatilized slowly, and the charge transport material contained in the coating film is contained in a trace amount in the solvent or at the end of the polyester resin. It can suppress that it decomposes | disassembles by a peroxide etc. Further, it is conceivable that the solvent volatilizes slowly, thereby causing a change in the compatibility between the polyester resin and the charge generation material, and making it possible to reduce the residual potential in the polyester-containing layer.

On the other hand, under relatively high temperature conditions, it is possible to completely volatilize the solvent that is considered to be one of the causes of residual potential accumulation. Therefore, it is possible to completely volatilize the solvent without decomposing the charge transport material, etc., for example, by drying under relatively low temperature conditions and then under relatively high temperature conditions. Thus, it is considered that a polyester-containing layer with little residual potential accumulation can be formed.
Further, it is known that the polyester resin represented by the above formula (1) used in the present invention has a large elastic deformation rate and a low melting point among general resins used in electrophotographic photoreceptors. It has been. Therefore, as compared with polycarbonate resin or the like, the state of the obtained coating film is easily affected by the solvent volatilization conditions when forming the coating film. Because it is a soft resin, for example, it is thought that the entanglement between the resin and the charge transport material becomes effective by slowly drying in stages from a low temperature, and it is thought that a coating film with less defects and better electron transport properties can be formed. .
Hereinafter, the method for forming a polyester-containing layer and the polyester-containing layer to be formed in the present invention will be described first, and then other configurations in the electrophotographic photoreceptor will be described.

<Method for producing electrophotographic photoreceptor>
In the method for producing an electrophotographic photoreceptor of the present invention, a polyester-containing layer is formed by applying a coating solution containing a polyester resin, and further drying the coating film coated with the coating solution under a plurality of temperature conditions. .
Here, in the present invention, the photosensitive layer formed on the electrophotographic photosensitive member is not particularly limited as long as the effects and objects of the present invention are not impaired. For example, the photosensitive layer contains a charge generation layer containing a charge generation material and a charge transport material. It may be a laminated photosensitive layer composed of a charge transporting layer, or a single-layered photosensitive layer in which a charge generating material is dispersed in a layer containing a charge transporting material.

  When the photosensitive layer is a single layer type, the photosensitive layer itself is a polyester-containing layer. On the other hand, when the photosensitive layer is a laminated type photosensitive layer in which a charge generation layer and a charge transport layer are laminated, one of the charge generation layer and the charge transport layer is the polyester-containing layer. Alternatively, both layers may be the polyester-containing layer. In the present invention, it is particularly preferable that the layer formed on the outer surface side of the electrophotographic photosensitive member, that is, the layer formed on the side opposite to the conductive support is the polyester-containing layer. As a result, the mechanical strength of the laminated photosensitive layer and the accumulation of residual potential can be reduced. Specifically, in an electrophotographic photosensitive member having a general laminated photosensitive layer, a charge generation layer is formed on the conductive support side, and a charge transport layer is formed on the charge generation layer. In the electrophotographic photosensitive member having such a configuration, the charge transport layer is preferably a polyester-containing layer. Hereinafter, the coating liquid used for forming the polyester-containing layer and the formation of the polyester-containing layer will be described.

(Coating solution)
The coating solution used for forming the polyester-containing layer is appropriately selected according to the type of photosensitive layer to which the polyester-containing layer is applied. For example, for the formation of a single-layer type photosensitive layer, a coating solution in which a polyester resin, a charge generation material, a charge transport material, and a solvent described later are mixed can be used. In the case where the multilayer charge generation layer is a polyester-containing layer, for example, a coating solution in which a polyester resin, a charge generation material, and a solvent are mixed can be used. Furthermore, when the multilayer charge transport layer is a polyester-containing layer, a coating solution in which a polyester resin, a charge transport material, and a solvent are mixed can be used. Hereinafter, each material contained in the coating liquid used for forming the polyester-containing layer will be described.

(1) Polyester resin Although there is no restriction | limiting in particular as long as the polyester resin used for formation of a polyester content layer does not impair the objective and effect of this invention, Preferably, it has a repeating structure represented by following formula (1) Is used. Hereinafter, the polyester resin having a repeating structure represented by the following formula (1) will be mainly described.

（式（１）中、Ａｒ¹及びＡｒ²は置換基を有していてもよいアリーレン基を表し、Ｘ¹及びＹ¹は２価の連結基を表す。）

(In Formula (1), Ar ¹ and Ar ² represent an arylene group which may have a substituent, and X ¹ and Y ¹ represent a divalent linking group.)

  The repeating structure represented by the above formula (1) is composed of a divalent hydroxy residue and a dicarboxylic acid residue. The structures of these divalent hydroxy residues and dicarboxylic acid residues have various effects on the polyester resin. Therefore, it is desirable that the structures of the divalent hydroxy residue and the dicarboxylic acid residue are appropriately set as appropriate.

Here, Ar < ¹ > and Ar < ² > in the said Formula (1) represent the arylene group which may have a substituent. Ar ¹ and Ar ² may be the same as or different from each other. Examples of the arylene group include divalent groups having an aromatic ring such as a phenylene group, a naphthylene group, and a phenanthrene group, and the number of aromatic rings is usually 5 or less, preferably the number of aromatic rings. Is 3 or less. Particularly preferred is a phenylene group.

In addition, the arylene group represented by Ar ¹ and Ar ² may have a substituent and can independently have a maximum of 4 substituents, but the number of substituents is preferably 2 or less. .
Examples of the substituent that the arylene group represented by Ar ¹ and Ar ² may have include an alkyl group, an alkoxy group, a halogen atom, and an aryl group. Moreover, these substituents may further have a substituent.

  The alkyl group as the substituent may be cyclic or chain-like, and the chain-like one may be linear or branched. A chain alkyl group is preferable, and a linear alkyl group is more preferable. Although there is no restriction | limiting in particular in carbon number which an alkyl group has, Preferably it is C1 or more, and is 10 or less normally, Preferably it is 5 or less. Examples of such alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and sec-pentyl. Group, n-hexyl group, and the like. Among them, a methyl group is preferable.

  The alkoxy group as the substituent may be cyclic or chain-like, and the chain-like one may be linear or branched. A linear alkoxy group is preferable, and a linear one is more preferable. Although there is no restriction | limiting in particular in carbon number which an alkoxy group has, Preferably it is C1 or more, and is 6 or less normally, Preferably it is 3 or less. Specific examples include a methoxy group and a butoxy group, and among them, a methoxy group is preferable.

  The aryl group as a substituent may be any group as long as it contains an aromatic ring, and preferably has 3 or less aromatic rings. Specific examples include a phenyl group, a naphthyl group, a phenanthyl group, a pyrenyl group, and the like, and a phenyl group is particularly preferable.

X ¹ represents a divalent linking group. Examples of the divalent linking group include a (cyclo) alkylene group, a sulfonyl group, —S—, —O—, —CR ¹ R ² —, or a direct bond (single bond) of Ar ¹ and Ar ² . R ¹ and R ² are each independently a hydrogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, an optionally substituted alkoxy group having 1 to 10 carbon atoms, A halogen atom or an aryl group having 6 to 20 carbon atoms which may have a substituent is shown. R ¹ and R ² may be bonded to each other to form a ring. Preferred groups as X ¹ include, for example, —O—, —S—, —SO—, —SO ₂ —, —CO—, —CH ₂ —, —CH (CH ₃ ) —, —C (CH ₃ ). _2- , cyclohexylidene and single bond are mentioned. Among these, —CH ₂ —, —CH (CH ₃ ) —, —C (CH ₃ ) ₂ —, and cyclohexylidene are preferable, and —CH ₂ —, —CH (CH ₃ ) —, cyclohexylene are particularly preferable. Den.

On the other hand, Y ¹ in the formula (1) represents a divalent linking group, and is preferably a group represented by the following formula (2) or an arylene group which may have a substituent (hereinafter, this arylene as appropriate). The group is represented by “Ar ⁵ ”).

（式（２）中、Ａｒ³、Ａｒ⁴は置換基を有していてもよいアリーレン基を表す。）

(In formula (2), Ar ³ and Ar ⁴ represent an arylene group which may have a substituent.)

When Y ¹ is a group represented by the formula (2), the above formula (1) is represented by the following formula (3).

（式（３）中、Ａｒ¹〜Ａｒ⁴は置換基を有していてもよいアリーレン基を表し、Ｘ¹は２価の連結基を表す。）

(In Formula (3), Ar ^{1 to} Ar ⁴ represent an arylene group which may have a substituent, and X ¹ represents a divalent linking group.)

In Formula (2), Ar ³ and Ar ⁴ represent an arylene group that is explained in the same manner as the arylene group represented by Ar ¹ and Ar ² . However, Ar ³ and Ar ⁴ may be the same as or different from Ar ¹ and Ar ² described above.

On the other hand, when Y ¹ is Ar ⁵ , the above formula (1) is represented by the following formula (4).

（式（４）中、Ａｒ¹及びＡｒ²は置換基を有していてもよいアリーレン基を表し、Ｘ¹は２価の連結基を表す。またＡｒ⁵は置換基を有していてもよいアリーレン基を表す。）

(In Formula (4), Ar ¹ and Ar ² represent an arylene group which may have a substituent, X ¹ represents a divalent linking group, and Ar ⁵ may have a substituent. Represents a good arylene group.)

In the above formula (4), Ar ⁵ represents an arylene group which may have a substituent explained in the same manner as the arylene group represented by Ar ¹ and Ar ² . However, Ar ⁵ may be the same as or different from Ar ¹ and Ar ² described above. That is, Ar ¹ , Ar ² and Ar ⁵ each independently represent an arylene group which may have a substituent.

  Further, the polyester resin used in the present invention may be a copolymer having one or more repeating structures selected from the repeating structure represented by the above formula (1), and is generally electrophotographic photosensitive. A copolymer having one or more types of repeating structures possessed by other resins that can be used in the body, and one or more types of repeating structures selected from the repeating structures represented by the above formula (1); You can also

  The polyester resin used in the coating solution is selected from one or more repeating structures of other resins that can be generally used for electrophotographic photoreceptors and the repeating structure represented by the above formula (1). In the case of a copolymer having one type or a plurality of types of repeating structures, examples of the repeating structure of other resins include a repeating structure of a polycarbonate resin and a repeating structure of a polyester resin other than the above. .

Among these, it is particularly preferable to use one or more kinds of copolymers selected from the repeating structure represented by the above formula (1), or a copolymer having a plurality of repeating structures, and Y ¹ is the same or a plurality of kinds. It is more preferable that the copolymer has a repeating structure of In addition, in this invention, the polyester resin mentioned above can be used 1 type or 2 types or more by arbitrary ratios and combinations.

  Further, the above-mentioned polyester resin usually has a viscosity average molecular weight of 8,000 or more, preferably 15,000 or more, and more preferably 20,000 or more. Moreover, it is 300,000 or less normally, Preferably it is 100,000 or less, More preferably, it is 50,000 or less. When the viscosity average molecular weight is less than 8,000, the mechanical strength of the resin tends to decrease. When the viscosity average molecular weight is more than 300,000, when the photosensitive layer is formed on the conductive support, it is applied to an appropriate film thickness. It may be difficult to apply the liquid.

  Moreover, in this invention, it is also possible to mix the polyester resin which has a repeating structure represented by the said Formula (1), and other resin, and to use for a coating liquid. Examples of other resins used in combination here include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, polycarbonates, and structures other than the repeating structure represented by the above formula (1). Examples thereof include thermoplastic resins such as polyester, polyester polycarbonate, polysulfone, phenoxy, epoxy, and silicone resin, and various thermosetting resins. These can be used alone or in combination of two or more in any ratio and combination. . Among these resins, a polycarbonate resin or a polyester polycarbonate resin is preferable, and a polyester polycarbonate resin is particularly preferable.

  The amount of the other resin to be used in combination is not particularly limited as long as the object and effect of the present invention are not impaired, and may be in any proportion, but when the polyester-containing layer is formed, the amount of the other resin is It is preferable not to exceed the amount of the polyester resin having the repeating structure represented by the formula (1) described above. That is, it is preferable that the content (% by weight) of the other resin contained in the solid content of the coating liquid does not exceed the content (% by weight) of the polyester resin contained in the solid content of the coating liquid. . More preferably, it is 20 weight% or less with respect to the polyester resin which has a repeating structure represented by the said Formula (1). If the amount of the other resin used in combination is too large, the effect of the polyester resin tends to be small.

  As the usage-amount of the said polyester resin, it can be set as the following range. For example, in the coating solution used for forming the charge transport layer of the laminated photosensitive layer, the solid content of the coating solution is usually 30% by weight or more, preferably 40% by weight or more, more preferably 50% by weight or more. Moreover, it is 85 weight% or less normally, Preferably it is 75 weight% or less, More preferably, it is 70 weight% or less.

  Further, in the coating solution used for forming the charge generation layer of the multilayer photosensitive layer, the solid content of the coating solution is usually 10% by weight or more, preferably 15% by weight or more, more preferably 30% by weight or more. . Moreover, it is 75 weight% or less normally, Preferably it is 65 weight% or less, More preferably, it is 60 weight% or less.

  Furthermore, in the coating solution used for the formation of the single layer type photosensitive layer, the solid content of the coating solution is usually 30% by weight or more, preferably 40% by weight or more, more preferably 45% by weight or more. Moreover, it is 75 weight% or less normally, Preferably it is 65 weight% or less, More preferably, it is 60 weight% or less.

  The production method of the polyester resin used in the present invention is not particularly limited as long as the object and effect of the present invention are not impaired, and can be the same as the production method of a general polyester resin. Hereinafter, the manufacturing method of the polyester resin which has a repeating structure represented by Formula (1) mentioned above is demonstrated in detail. As a method for producing the polyester resin, a known polymerization method can be used. Examples thereof include an interfacial polymerization method, a melt polymerization method, and a solution polymerization method.

  For example, in the case of production by an interfacial polymerization method, a solution in which a divalent hydroxy compound is dissolved in an alkaline aqueous solution and a halogenated hydrocarbon solution in which an aromatic dicarboxylic acid chloride is dissolved are mixed. At this time, a quaternary ammonium salt or a quaternary phosphonium salt may be present as a catalyst. The polymerization temperature is preferably in the range of 0 to 40 ° C., and the polymerization time is preferably in the range of 2 to 20 hours from the viewpoint of productivity. After completion of the polymerization, the water phase and the organic phase are separated, and the polymer dissolved in the organic phase is washed and recovered by a known method, whereby the intended resin can be obtained.

  Examples of the alkali component used in the interfacial polymerization method include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide. As the usage-amount of an alkali, the range of 1.01-3 times equivalent of the phenolic hydroxyl group contained in a reaction system is preferable.

  Examples of the halogenated hydrocarbon include dichloromethane, chloroform, 1,2-dichloroethane, trichloroethane, tetrachloroethane, dichlorobenzene, and the like. In addition, a halogenated hydrocarbon may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  Furthermore, examples of the quaternary ammonium salt or quaternary phosphonium salt used as the catalyst include, for example, salts of tertiary alkylamines such as tributylamine and trioctylamine such as hydrochloric acid, bromic acid, and iodic acid; benzyltriethylammonium chloride, benzyl Trimethylammonium chloride, benzyltributylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, trioctylmethylammonium chloride, tetrabutylphosphonium bromide, triethyloctadecylphosphonium bromide, N-laurylpyridinium chloride, laurylpicolinium chloride, etc. Is mentioned. In addition, a catalyst may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and ratios.

  In the interfacial polymerization method, a molecular weight regulator can be used. Examples of the molecular weight regulator include phenol, o, m, p-cresol, o, m, p-ethylphenol, o, m, p-propylphenol, o, m, p- (tert-butyl) phenol, and pentyl. Alkylphenols such as phenol, hexylphenol, octylphenol, nonylphenol, 2,6-dimethylphenol derivatives and 2-methylphenol derivatives, monofunctional phenols such as o, m, p-phenylphenol, acetic acid chloride, butyric acid chloride, octyl Examples thereof include monofunctional acid halides such as acid chloride, benzoyl chloride, benzenesulfonyl chloride, benzenesulfinyl chloride, sulfinyl chloride, benzenephosphonyl chloride, and substituted products thereof.

  Among these molecular weight regulators, o, m, p- (tert-butyl) phenol, 2,6-dimethylphenol derivatives, 2-methylphenol derivatives are preferred because of their high molecular weight controllability and solution stability. Particularly preferred are p- (tert-butyl) phenol, 2,3,6-tetramethylphenol, and 2,3,5-tetramethylphenol. In addition, a molecular weight regulator may also be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

(2) Solvent The coating solution usually contains a solvent, and the polyester resin is present in a state dissolved or dispersed in the solvent in the coating solution. Especially, it is preferable that the said polyester resin exists in the state melt | dissolved in the solvent.

The type of the solvent used in the coating solution is not particularly limited, and any solvent can be used as long as it can dissolve or disperse the polyester resin as long as the effects of the present invention are not significantly impaired. For example, alcohols such as methanol, ethanol, propanol and 2-methoxyethanol; ethers such as tetrahydrofuran, 1,4-dioxane and dimethoxyethane; esters such as methyl formate and ethyl acetate; acetone, methyl ethyl ketone and cyclohexanone Ketones; aromatic hydrocarbons such as benzene, toluene, xylene; dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-di Chlorinated hydrocarbons such as chloropropane and trichloroethylene; nitrogen-containing compounds such as n-butylamine, isopropanolamine, diethylamine, triethanolamine, ethylenediamine and triethylenediamine; acetonitrile, N- Methylpyrrolidone, N, N- dimethylformamide, aprotic polar solvents such as dimethyl sulfoxide and the like.
In addition, a solvent may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  Moreover, when using a solvent, there is no restriction | limiting in the usage-amount. However, when the coating solution is used for forming a charge transport layer of a single layer type photosensitive layer or a multilayer type photosensitive layer, the solid content concentration of the coating solution is usually 10% by weight or more, preferably 15% by weight or more, It is desirable to adjust the amount of solvent used so that it is usually in the range of 40% by weight or less, preferably 35% by weight or less. Thereby, a layer with a more uniform film thickness can be formed.

  At this time, in order to keep the coating property of the coating solution good, the viscosity of the coating solution is usually 50 mPa · s or more, preferably 100 mPa · s or more, and usually 1000 mPa · s or less, preferably 600 mPa · s or less. It is desirable to adjust the composition and use amount of the solvent so that the above range is satisfied.

  On the other hand, when the coating solution is used for forming the charge generation layer of the laminated photosensitive layer, the solid content concentration of the coating solution is usually 1% by weight or more, preferably 2% by weight or more, and usually 15% by weight or less. It is desirable to adjust the amount of solvent used so that it is preferably in the range of 10% by weight or less. Further, in order to keep the coating property of the coating solution good, the viscosity of the coating solution is usually 0.1 mPa · s or more, preferably 0.5 mPa · s or more, and usually 10 mPa · s or less, preferably 8 mPa · s. It is desirable to adjust the composition and use amount of the solvent so as to be in the range of s or less. If the viscosity is too low, it is difficult to form a uniform coating film, and if the viscosity is too high, a sufficient drying effect may not be obtained.

(3) Charge generation material When the coating solution is used for forming a single layer type photosensitive layer or a charge generation layer of a multilayer type photosensitive layer, the coating solution usually contains a charge generation material. The charge generation substance is a substance that exhibits a charge generation function and is contained in the charge generation layer of the single-layer type photosensitive layer or the multilayer light emitting layer.

  Examples of charge generation materials include selenium and its alloys, cadmium sulfide, and other inorganic photoconductive materials; phthalocyanine pigments, azo pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, benzimidazole pigments Various photoconductive materials such as organic pigments; Among these, organic pigments are particularly preferable, and phthalocyanine pigments and azo pigments are more preferable.

  In particular, when a phthalocyanine compound is used as the charge generation material, for example, metal such as metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, or coordination thereof, such as oxide or halide Phthalocyanines are used. Examples of the ligand to the trivalent or higher metal atom include a hydroxyl group and an alkoxy group in addition to the oxygen atom and chlorine atom shown above. Among them, particularly sensitive X-type, τ-type metal-free phthalocyanine, A-type, B-type, D-type titanyl phthalocyanine, vanadyl phthalocyanine, chloroindium phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, and the like are preferable.

  Of the crystal forms of titanyl phthalocyanine mentioned here, A type and B type are described in W.W. It has been shown by Heller et al. As phase I and phase II (Zeit. Kristallogr. 159 (1982) 173), respectively, and type A is known as a stable type. The D-type is a crystal type characterized by a clear peak at a diffraction angle 2θ ± 0.2 ° of 27.3 ° in powder X-ray diffraction using CuKα rays.

  In addition, the charge generation material may be used alone or in combination of two or more in any combination and ratio. Furthermore, when two or more charge generation materials are used in combination, the charge generation material used in combination and the mixed state in the crystalline state may be used by mixing the respective constituent elements later, or synthesis, pigmentation Alternatively, a mixed state may be generated and used in the charge generation material production / treatment process such as crystallization. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known.

  In particular, in the case of a single-layer type photosensitive layer, it is desirable that the particle size of the charge generating material is sufficiently small. Specifically, it is usually 1 μm or less, preferably 0.5 μm or less.

  Furthermore, the content of the charge generating substance in the coating solution is arbitrary as long as the effects of the present invention are not significantly impaired. However, when the coating solution is used for forming the charge generation layer of the laminated photosensitive layer, the amount of the charge generation material in the coating solution is the binder resin in the coating solution (for example, the total of the polyester resin and other resins). The amount is usually 30 parts by weight or more, preferably 50 parts by weight or more, more preferably 100 parts by weight or more with respect to 100 parts by weight. Moreover, it is 500 parts weight or less normally, Preferably it is 300 parts weight or less, More preferably, it is 200 parts weight or less. If the amount of the charge generating material is too small, sufficient sensitivity may not be obtained. If the amount is too large, the chargeability of the electrophotographic photosensitive member may be lowered, or the sensitivity may be lowered.

  Further, when the coating solution is used for forming a monolayer type photosensitive layer, the amount of the charge generating substance in the solid content in the coating solution is usually 0.5% by weight or more, preferably 1% by weight. In addition, it is usually adjusted to 50% by weight or less, preferably 20% by weight or less. If the amount of the charge generating material is too small, sufficient sensitivity may not be obtained. If the amount is too large, the chargeability of the electrophotographic photosensitive member may be lowered, or the sensitivity may be lowered.

(4) Charge transporting material When the coating solution is used for forming a charge transporting layer of a single layer type photosensitive layer or a multilayer type photosensitive layer, the coating solution usually contains a charge transporting material. This charge transport material fulfills a charge transport function in the charge transport layer of the single layer type photosensitive layer or the multilayer type photosensitive layer when the photosensitive layer is formed.

  The charge transport material is not particularly limited, and any material can be used. Examples of 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, carbazole derivatives, indoles 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 multiple types of these compounds bind Or an electron donating substance such as a polymer 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 and ratio.

  Specific examples of suitable structures of the charge transport material are shown below. However, these specific examples are shown for illustration, and any known charge transport material may be used as long as it is not contrary to the gist of the present invention. “T-Bu” represents a t-butyl group.

  The content of the charge transport material in the coating solution is arbitrary as long as the effects of the present invention are not significantly impaired. However, in the case where the coating solution is used for forming any of the single layer type photosensitive layer and the charge transport layer of the laminated type photosensitive layer, the amount of the charge transport material in the coating solution is the binder resin in the coating solution (for example, The total of 100 parts by weight of the polyester resin and other resins according to the present invention is usually 30 parts by weight or more, preferably 40 parts by weight or more, more preferably 50 parts by weight or more, and usually 200 parts by weight or less. It is preferably 150 parts by weight or less, more preferably 100 parts by weight or less. If the amount of the charge transport material is too small, the electrical characteristics may be deteriorated. If the amount is too large, the coating film becomes brittle and the wear resistance may be deteriorated.

(5) Additives, etc. The coating solution may appropriately contain components other than those described above.
For example, the coating solution may contain a known additive. These additives are used, for example, to improve the film formability, flexibility, coatability, stain resistance, gas resistance, light resistance, mechanical strength, and the like of the photosensitive layer. Examples of additives include antioxidants, plasticizers, ultraviolet absorbers, electron withdrawing compounds, dyes, pigments and the like. In particular, examples of dyes and pigments include various pigment compounds and azo compounds. In addition, residual potential inhibitors for suppressing residual potential, dispersion aids for improving dispersion stability, leveling agents (for example, silicone oil, fluorine-based oil, etc.) for improving coating properties, surfactants Etc. can also be used as additives.
In addition, an additive may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

(Formation of polyester-containing layer)
(1) Application of coating solution In the present invention, when forming the polyester-containing layer in the photosensitive layer, the above-described coating solution is applied directly on the conductive support or through an undercoat layer or other layers. Then, a coating film is formed. The method for applying the coating solution described above onto the conductive support is not particularly limited as long as the object and effect of the present invention are not impaired, and is appropriately selected according to the type of the photosensitive layer and the like. Examples of coating methods include dip coating, spray coating, nozzle coating, bar coating, roll coating, blade coating, and the like. Among these, the dip coating method is preferable because of its high productivity. Note that these coating methods may be performed by only one method, or may be performed by combining two or more methods.

  In this invention, the temperature at the time of application | coating of a coating liquid is 10 degreeC or more normally, Preferably it is 20 degreeC or more, More preferably, it is 22 degreeC or more. Moreover, it is 35 degrees C or less normally, Preferably it is 30 degrees C or less, More preferably, it is 27 degrees C or less. The relative humidity at the time of application of the coating solution is usually 10% or more, preferably 20% or more, more preferably 30% or more. Moreover, it is 70% or less normally, Preferably it is 60% or less, More preferably, it is 50% or less.

(2) Drying of coating film In the present invention, the coating film applied directly on the conductive support or via an undercoat layer or the like is dried under a plurality of temperature conditions. The temperature condition for drying the coating film is not particularly limited as long as the object and effect of the present invention are not impaired, but usually, relatively low temperature and relatively high temperature conditions are selected. As a result, as described above, the charge transporting material or the charge generating material contained in the polyester-containing layer is hardly decomposed, and the solvent considered to be one of the causes of residual potential accumulation is completely volatilized. Is possible.

  The order of performing drying at a relatively low temperature and drying at a relatively high temperature is not particularly limited, and either may be performed first. However, after drying under a relatively low temperature condition, Dry under high temperature conditions. This makes it possible to manufacture an electrophotographic photosensitive member having better electrical characteristics.

  The method for drying the coating film under each temperature condition is not particularly limited as long as the object and effect of the present invention are not impaired, and a method capable of drying the coating film within a set temperature range can be appropriately selected and used. Examples of the apparatus for drying include a dryer such as a hot air dryer, a steam dryer, an infrared dryer, a far-infrared dryer, and a heating device such as a constant temperature and humidity oven, or an oven. One type or two or more types can be used in any combination per condition.

  In the present invention, the temperature in the atmosphere when the coating film is heated is considered as the drying temperature. The atmosphere at the time of heating may be the same as in the air, but may be an atmosphere from which particles and gas that affect the dust and the photosensitive layer are removed through a filter or the like. Moreover, humidity control during drying is arbitrary.

  Specifically, among the plurality of temperature conditions in the present invention, the relatively high temperature condition is usually 115 ° C. or higher, and more preferably a temperature equal to or higher than the boiling point of all the solvents contained in the coating solution. Moreover, an upper limit is 170 degreeC normally, Preferably it is 140 degrees C or less. If the temperature is too high, decomposition of the material contained in the coating film may occur due to heat, and the photosensitive properties of the polyester-containing layer may deteriorate. Moreover, since a great deal of energy is required to raise the temperature, there is a possibility that the productivity will be significantly reduced. On the other hand, when the final drying temperature is 115 ° C. or lower, the solvent in the coating film may not completely evaporate, and the solvent may remain in the polyester-containing layer. If the solvent remains in the polyester-containing layer, it may cause residual potential accumulation when the polyester-containing layer is repeatedly used. Therefore, for example, as a final stage of drying, by performing drying under the above temperature condition, the solvent in the coating film can be completely removed, and a polyester-containing layer is formed that is less likely to accumulate residual potential. be able to.

  Moreover, as a relatively low temperature condition, it is preferable that the temperature is usually 70 ° C. or higher and usually 115 ° C. or lower. The purpose of drying in the above temperature range is to reduce the amount of solvent in the coating film to some extent under mild conditions. When a photosensitive layer containing a large amount of a solvent is dried in a high temperature atmosphere exceeding 115 ° C., the residual potential may be increased. On the other hand, by holding the coating film at a temperature of 115 ° C. or lower, it is possible to reduce the residual potential of the polyester resin that is usually high. The reason for this is not clear. For example, the charge transport material contained in the polyester-containing layer can be prevented from being decomposed by a peroxide contained in a trace amount in the terminal or coating solvent of the polyester resin, It is conceivable that a change occurs in the compatibility between the charge generating material and the charge generation material.

In the present invention, in addition to the above-described temperature range, it is possible to provide a lower temperature condition or an intermediate temperature condition.
In the present invention, drying is preferably performed under a temperature condition of two or more stages, and usually it is preferably 5 stages or less, more preferably 4 stages or less.

  The drying time under each temperature condition can be arbitrarily selected, but is usually 3 minutes or more, preferably 5 minutes or more. Moreover, it is normally 60 minutes or less, Preferably it is 30 minutes or less. If it is too short, a sufficient solvent removal effect may not be obtained, and if it is too long, decomposition of the material in the coating film may occur.

(3) Other steps In the method for producing an electrophotographic photosensitive member of the present invention, other steps may be appropriately included as necessary before, during or after the step of forming the polyester-containing layer. .

<Electrophotographic photoreceptor>
The electrophotographic photosensitive member of the present invention is configured to have a photosensitive layer on a conductive support. If the photosensitive layer includes the above-described polyester-containing layer, the layer configuration is particularly limited. There is no. As described above, the photosensitive layer may be a laminated photosensitive layer in which a charge generation layer and a charge transport layer are laminated, or may be a single layer type photosensitive layer containing a charge transport material and a charge generation material. . In the case where the photosensitive layer is a laminated photosensitive layer, the order of stacking the charge transport layer and the charge generation layer is not particularly limited, and any layer may be formed on the conductive support side. Since it is possible to enhance the durability of the photosensitive layer, it is preferable to have a charge generation layer on the conductive support side and a charge transport layer on the charge generation layer. Hereinafter, each configuration of the electrophotographic photosensitive member of the present invention will be described.

(Photosensitive layer)
As described above, the photosensitive layer formed on the electrophotographic photosensitive member of the present invention includes at least a polyester-containing layer formed by the above-described method, and does not impair the effects and objects of the present invention. There is no particular limitation, and for example, it may be a laminated photosensitive layer composed of a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material, or a layer containing a charge transport material. It may be a single layer type photosensitive layer in which a charge generating substance is dispersed. Hereinafter, the photosensitive layer (the charge generation layer, the charge transport layer, and the single-layer type photosensitive layer of the laminated photosensitive layer) in the electrophotographic photoreceptor produced according to the present invention will be described in detail.

(1) Charge Generation Layer in Multilayer Type Photosensitive Layer The charge generation layer is a layer containing a charge generation material as described above. As the charge generation material, those described in the section of the polyester-containing layer described above can be used. In the normal charge generation layer, the binder resin usually binds the charge generation material. In addition, when the charge generation layer is a polyester-containing layer, the polyester resin can be a binder resin. In this case, a polyester resin and other resins may be used alone or in combination of two or more to form a binder resin. When the charge generation layer is not a polyester-containing layer, the type of binder resin is not particularly limited as long as the object and effect of the present invention are not impaired. Examples of resins other than the polyester resin that can be used for the binder resin include, for example, polyvinyl acetate, polyacrylic acid ester, polymethacrylic acid ester, polycarbonate, polyvinyl acetoacetal, polyvinyl propional, polyvinyl butyral, phenoxy resin, epoxy resin, and urethane resin. , Cellulose ester, cellulose ether and the like. In the charge generation layer, one binder resin may be used alone, or two or more binder resins may be used in any combination and ratio.

  The amount of the charge generating material used is arbitrary as long as the effects of the present invention are not significantly impaired. However, it is desirable that the range satisfies the condition of the ratio between the charge generation material and the binder resin mentioned in the section of the charge generation material.

  Further, the film thickness of the charge generation layer is not limited, but is usually 0.1 μm or more, preferably 0.15 μm or more, and usually 1 μm or less, preferably 0.6 μm or less. The charge generation layer may contain an antioxidant and other additives.

  The method for forming the charge generation layer is appropriately selected depending on the type of the coating solution. For example, when the charge generation layer is a polyester-containing layer, the charge generation layer may be formed by the method described in the above-described method for forming a polyester-containing layer. it can. When a resin other than the polyester resin is used as the binder resin and the charge generation layer is formed, the method is appropriately selected according to the type of the resin. For example, it can be formed by applying a coating solution for forming a charge generation layer on a conductive support or through an undercoat layer, and drying or curing the coating liquid according to the type of the binder resin.

(2) Charge transport layer in the multilayer photosensitive layer The charge transport layer in the multilayer photosensitive layer is a layer containing a charge transport material. When the charge generation layer is not the polyester-containing layer, the type of binder resin and the like used for the charge transport layer is not particularly limited, but in the present invention, the charge transport layer may be a polyester-containing layer. preferable. In such a charge transport layer, the charge transport material is usually bound with a polyester resin. In the charge transport layer, the above-mentioned polyester resin may be used alone as the binder resin, or two or more polyester resins may be used in any combination and ratio. Moreover, you may use a polyester resin and another resin by arbitrary combinations and a ratio. As the binder resin used for the charge transport layer, those described in the above-mentioned section of the polyester resin can be used.

  The amount of the charge transport material used is arbitrary as long as the effects of the present invention are not significantly impaired. However, it is desirable that the range satisfies the condition of the ratio between the charge transport material and the binder resin described in the description of the charge transport material.

  The thickness of the charge transport layer is not limited, but is usually 5 μm or more, preferably 10 μm or more, and usually 50 μm or less from the viewpoint of enhancing durability and obtaining a long-life electrophotographic photosensitive member. From the viewpoint of increasing the resolution of the image to be printed, it is preferably 45 μm or less.

  Furthermore, when the charge transport layer is a polyester-containing layer, the charge transport layer preferably contains an antioxidant in order to prevent oxidation. Usually, when an antioxidant is contained in the charge transport layer, the electrical properties and wear resistance may be reduced. However, in the present invention, even if an antioxidant is contained, it depends on a plurality of temperature steps. By performing the drying, it is possible to improve the electrical characteristics and wear resistance of the charge transport layer. The usage-amount of antioxidant is arbitrary unless the effect of this invention is impaired remarkably.

The charge transport layer may contain other additives in order to improve film forming properties, flexibility, coating properties, contamination resistance, gas resistance, light resistance, and the like.
Furthermore, the charge transport layer may be composed of a single layer, or may be a stack of a plurality of layers having different components or composition ratios. When the charge transport layer is formed of a plurality of layers, it is preferable that at least one layer is the polyester-containing layer.

  As a method for forming the charge transport layer, for example, when the charge transport layer is a polyester-containing layer, the charge transport layer can be formed by the method described in the above-described method for forming a polyester-containing layer. When a resin other than the polyester resin is used as the binder resin and the charge transport layer is formed, the method is appropriately selected according to the type of the resin. For example, it is formed by applying a coating solution for forming a charge transport layer on a conductive support or via an undercoat layer or a charge generation layer, and drying or curing depending on the type of binder. Can do.

(3) Single-layer type photosensitive layer The single-layer type photosensitive layer is formed by the above-described method for forming a polyester-containing layer, and is a layer in which a charge generation material is dispersed in a layer containing a polyester resin and a charge transport material. be able to. The charge transport material, polyester resin, and other types of resins in the single-layer type photosensitive layer, and the usage ratio thereof, are the same as those described in the section of the charge transport layer in the laminated photosensitive layer. Can do. Moreover, the kind of charge generation material is as described above. However, in this case, the particle size of the charge generation material is preferably sufficiently small, and specifically, is preferably within the range described in the section of the charge generation material.

Furthermore, if the amount of the charge generating material dispersed in the single-layer type photosensitive layer is too small, sufficient sensitivity may not be obtained, and if it is too large, the chargeability may be lowered or the sensitivity may be lowered. . Therefore, the amount of the charge generating material in the single-layer type photosensitive layer is preferably in a range that satisfies the condition of the ratio of the charge generating material to the binder resin mentioned in the section of the charge generating material.
The single layer type photosensitive layer may contain an additive in the same manner as the charge generation layer and the charge transport layer.

  The film thickness of the single-layer type photosensitive layer is arbitrary, but is usually 5 μm or more, and is preferably 10 μm or more from the viewpoint of enhancing durability and obtaining a long-life electrophotographic photosensitive member. Further, it is usually 50 μm or less, and preferably 45 μm or less from the viewpoint of increasing the resolution of the formed image.

(Conductive support)
Although there is no restriction | limiting in particular in the electroconductive support body used for the electrophotographic photosensitive member of this invention, For example, metal materials, such as aluminum, aluminum alloy, stainless steel, copper, nickel; Conductive powder, such as a metal, carbon, a tin oxide Mainly used are resin materials, such as aluminum, nickel, ITO (indium-tin oxide), etc. deposited on or coated on the surface thereof, glass, paper, and the like. Moreover, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  Furthermore, as a form of the conductive support, for example, a drum shape, a sheet shape, a belt shape or the like is used. Further, a conductive material having an appropriate resistance value may be coated on a conductive support made of a metal material in order to control conductivity and surface properties or to cover defects.

Further, when a metal material such as an aluminum alloy is used as the conductive support, it may be used after anodizing, chemical conversion coating or the like. When the anodizing treatment is performed, it is desirable to perform a sealing treatment by a known method.
The surface of the support may be smooth, or may be roughened by using a special cutting method or performing a polishing treatment. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the conductive support.

(Underlayer)
An undercoat layer may be provided between the conductive support and the photosensitive layer in order to improve adhesion and blocking properties. As the undercoat layer, a resin, a resin in which particles such as metal oxide (usually inorganic particles) are dispersed, or the like is used.

  Examples of metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. One kind of these particles may be used alone, or a plurality of kinds of particles may be mixed and used.

  Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicone. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. A thing of a several crystalline state may be contained.

  In addition, various particle sizes of the metal oxide particles can be used. Among these, from the viewpoint of characteristics and liquid stability, the average primary particle size is usually 1 nm or more, preferably 10 nm or more, and usually 100 nm. Hereinafter, it is preferably 50 nm or less.

  The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. Examples of the binder resin used for the undercoat layer include phenoxy resin, epoxy resin, polyvinyl pyrrolidone, polyvinyl alcohol, casein, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, and the like. Among these, alcohol-soluble copolymerized polyamide, modified polyamide, and the like are preferable because they exhibit good dispersibility and coating properties. The binder resin for the undercoat layer may be used alone or in combination of two or more in any combination and ratio. Furthermore, the binder resin can be used in the form of being cured together with the curing agent, in addition to being used only with the binder resin.

Moreover, although the usage-ratio of the particle | grains with respect to binder resin can be chosen arbitrarily, using in the range of 10 weight%-500 weight% normally is preferable in terms of the stability of a dispersion liquid, and applicability | paintability.
Further, the thickness of the undercoat layer is arbitrary as long as the effects of the present invention are not significantly impaired, but from the characteristics and applicability of the electrophotographic photoreceptor, it is usually preferably 0.1 μm to 25 μm. Further, the undercoat layer may contain an additive such as an antioxidant.

(Other layers)
In addition to the undercoat layer, the charge generation layer, the charge transport layer, and the single-layer type photosensitive layer, the electrophotographic photoreceptor may further include other layers.

  For example, a protective layer may be provided on the photosensitive layer for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the decomposition of the photosensitive layer due to discharge products generated from a charger or the like. Further, the outermost surface layer may contain, for example, a fluorine-based resin, a silicone resin, or the like for the purpose of reducing frictional resistance and wear on the surface of the electrophotographic photosensitive member. Compound particles may also be included.

  There is no restriction | limiting in the formation method of other layers, such as the said protective layer, As long as the effect of this invention is not impaired remarkably, it is arbitrary. For example, a known method such as sequentially applying a coating solution obtained by dissolving or dispersing a substance to be contained in a layer in a solvent can be applied.

B. Image Forming Apparatus Next, the image forming apparatus of the present invention will be described. The image forming apparatus of the present invention performs exposure on the electrophotographic photosensitive member produced by the above-described method for producing an electrophotographic photosensitive member, charging means for charging the electrophotographic photosensitive member, and the charged electrophotographic photosensitive member. And an image exposure means for forming an electrostatic latent image, a developing means for developing the electrostatic latent image with toner, and a transfer means for transferring the toner to a transfer medium.

  In the image forming apparatus using the electrophotographic photosensitive member manufactured by the above manufacturing method, since the photosensitive layer includes the polyester-containing layer, even if the electrophotographic photosensitive member is repeatedly used for image formation, The decrease in potential can be reduced, and the physical resistance can also be improved. Therefore, not only at the beginning of use, but also after repeated use and after applying mechanical and electrical loads, the change in the electrical characteristics of the electrophotographic photosensitive member is small, and an image can be formed with an optimal amount of toner ink. Is possible. In addition, an image forming apparatus capable of forming a high-quality image without causing an image defect such as an increase or decrease in image density.

  An embodiment of an image forming apparatus using an electrophotographic photosensitive member (an image forming apparatus of the present invention) will be described with reference to FIG. However, the embodiment is not limited to the following description, and can be arbitrarily modified without departing from the gist of the present invention.

  As shown in FIG. 1, the image forming apparatus includes an electrophotographic photosensitive member 1, a charging device (charging means) 2, an exposure device (exposure means; image exposure means) 3, a developing device (developing means) 4, and a transfer device ( The image forming apparatus may include a transfer device 5, and may optionally include a cleaning device (cleaning device) 6 and a fixing device (fixing device) 7.

  The electrophotographic photosensitive member 1 is not particularly limited as long as it is an electrophotographic photosensitive member manufactured by the above-described method. In FIG. 1, as an example, the above-described photosensitive layer is formed on the surface of a cylindrical conductive support. 2 shows a drum-shaped electrophotographic photosensitive member. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are arranged along the outer peripheral surface of the electrophotographic photoreceptor 1.

  The charging device 2 charges the electrophotographic photosensitive member 1 and uniformly charges the surface of the electrophotographic photosensitive member 1 to a predetermined potential. In FIG. 1, a roller-type charging device (charging roller) is shown as an example of the charging device 2, but other corona charging devices such as corotron and scorotron, and contact-type charging devices such as charging brushes are often used.

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

  The type of exposure apparatus 3 is not particularly limited as long as it can form an electrostatic latent image on the photosensitive surface of the electrophotographic photosensitive member 1 by performing exposure (image exposure) on the electrophotographic photosensitive member 1. Absent. Specific examples include halogen lamps, fluorescent lamps, lasers such as semiconductor lasers and He—Ne lasers, and LEDs (light emitting diodes). Further, exposure may be performed by a photoreceptor internal exposure method. The light at the time of exposure is arbitrary, but generally monochromatic light is preferable. For example, monochromatic light having a wavelength (exposure wavelength) of 700 nm to 850 nm, monochromatic light having a wavelength of 600 nm to 700 nm and slightly shorter wavelength, wavelength of 300 nm to 500 nm The exposure can be performed with monochromatic light having a short wavelength.

  The type of the developing device 4 is not particularly limited as long as it can develop the exposed electrostatic latent image on the electrophotographic photosensitive member 1 into a visible image. As a specific example, an arbitrary apparatus such as a dry development system such as cascade development, one-component conductive toner development, or two-component magnetic brush development, or a wet development system can be used. The developing device 4 in FIG. 1 includes a developing tank 41, an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45, and has a configuration in which toner T is stored inside the developing tank 41. Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing device 4 as necessary. The replenishing device is configured to be able to replenish toner T from a container such as a bottle or a cartridge.

  The supply roller 43 is formed from a conductive sponge or the like. The developing roller 44 is made of a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating such a metal roll with a silicone resin, a urethane resin, a fluorine resin, or the like. The surface of the developing roller 44 may be smoothed or roughened as necessary.

  The developing roller 44 is disposed between the electrophotographic photoreceptor 1 and the supply roller 43 and is in contact with the electrophotographic photoreceptor 1 and the supply roller 43, respectively. However, the developing roller 44 and the electrophotographic photosensitive member 1 may not be in contact with each other but may be close to each other. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism (not shown). The supply roller 43 carries the stored toner T and supplies it to the developing roller 44. The developing roller 44 carries the toner T supplied by the supply roller 43 and contacts the surface of the electrophotographic photosensitive member 1.

  The regulating member 45 is formed of a resin blade such as silicone resin or urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such metal blade with resin. The regulating member 45 normally abuts on the developing roller 44 and is pressed against the developing roller 44 side with a predetermined force by a spring or the like (a general blade linear pressure is 0.05 to 5 N / cm). If necessary, the regulating member 45 may be provided with a function of imparting charging to the toner T by frictional charging with the toner T.

  The agitator 42 is provided as necessary, and is rotated by a rotation driving mechanism, and agitates the toner T and conveys the toner T to the supply roller 43 side. A plurality of agitators 42 may be provided with different blade shapes and sizes.

  The type of the toner T is arbitrary, and in addition to the powdery toner, a polymerized toner using a suspension polymerization method, an emulsion polymerization method, or the like can be used. In particular, when a polymerized toner is used, a toner having a small particle diameter of about 4 to 8 μm is preferable, and the toner particles are used in a variety of shapes ranging from a nearly spherical shape to a potato-like spherical shape. be able to. The polymerized toner is excellent in charging uniformity and transferability and is suitably used for high image quality.

  The type of the transfer device 5 is not particularly limited, and an apparatus using an arbitrary system such as an electrostatic transfer method such as corona transfer, roller transfer, or belt transfer, a pressure transfer method, or an adhesive transfer method can be used. . Here, it is assumed that the transfer device 5 includes a transfer charger, a transfer roller, a transfer belt, and the like disposed so as to face the electrophotographic photoreceptor 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner T, and transfers a toner image formed on the electrophotographic photosensitive member 1 to a recording paper (paper, medium, transfer target). Transfer to P.

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

  The fixing device 7 includes an upper fixing member (pressure roller) 71 and a lower fixing member (fixing roller) 72, and a heating device 73 is provided inside the fixing member 71 or 72. FIG. 1 shows an example in which a heating device 73 is provided inside the upper fixing member 71. The upper and lower fixing members 71 and 72 are, for example, 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, a fixing sheet, or the like. A fixing member can be used. Further, the fixing members 71 and 72 may be configured to supply a release agent such as silicone oil in order to improve the releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

  When the toner transferred onto the recording paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated to a molten state and cooled after passing through the recording paper. Toner is fixed on P.

  The type of the fixing device is not particularly limited, and a fixing device of any type such as heat roller fixing, flash fixing, oven fixing, pressure fixing, etc. can be provided including those used here.

  In the image forming apparatus configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the electrophotographic photosensitive member 1 is charged to a predetermined potential (for example, −600 V) by the charging device 2. At this time, charging may be performed by a DC voltage, or charging may be performed by superimposing an AC voltage on the DC voltage.

  Subsequently, the photosensitive surface of the charged electrophotographic photosensitive member 1 is exposed by the exposure device 3 according to the image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. Then, development of the electrostatic latent image formed on the photosensitive surface of the electrophotographic photoreceptor 1 is performed by the developing device 4.

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

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

  The image forming apparatus may be further modified. For example, the image forming apparatus may be configured to perform processes such as a pre-exposure process and an auxiliary charging process, or may be configured to perform offset printing. A full-color tandem system configuration using toner may be used.

  The electrophotographic photosensitive member 1 is combined with one or more of the charging device 2, the exposure device 3, the developing device 4, the transfer device 5, the cleaning device 6, and the fixing device 7 to form an integrated cartridge ( The electrophotographic photosensitive member cartridge may be configured to be detachable from the main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. For example, at least one of the charging device 2, the exposure device 3, the developing device 4, and the transfer device 5 can be integrally supported together with the electrophotographic photosensitive member 1 to form a cartridge. Also in this case, similarly to the cartridge described in the above embodiment, for example, when the functions of the electrophotographic photosensitive member 1 and other members are deteriorated, the electrophotographic photosensitive member cartridge is removed from the main body of the image forming apparatus, and another new By attaching the electrophotographic photosensitive member cartridge to the main body of the image forming apparatus, maintenance and management of the image forming apparatus becomes easy.

C. Next, an electrophotographic cartridge using the electrophotographic photosensitive member will be described. The configuration of the electrophotographic cartridge is not particularly limited as long as it includes the above-described electrophotographic photosensitive member. For example, the electrophotographic photosensitive member, a charging unit for charging the electrophotographic photosensitive member, An image exposure means for exposing the electrophotographic photosensitive member to image formation to form an electrostatic latent image; a developing means for developing the electrostatic latent image with toner; a transfer means for transferring the toner to a transfer target; The image forming apparatus may include at least one selected from a fixing unit that fixes the toner transferred to the transfer member and a cleaning unit that collects the toner attached to the electrophotographic photosensitive member.

  The electrophotographic photosensitive member, charging unit, image exposing unit, developing unit, transfer unit, neutralizing unit, fixing unit, and cleaning unit used in the electrophotographic cartridge are each described in “A. Method for producing electrophotographic photosensitive member”. Or “B. Image forming apparatus”.

  In general, the electrophotographic photosensitive member cartridge can be configured to be detachable from a main body of an image forming apparatus such as a copying machine or a laser beam printer. In this case, for example, when the function of the electrophotographic photosensitive member or other member is deteriorated, the electrophotographic cartridge is removed from the main body of the image forming apparatus, and another new electrophotographic cartridge is attached to the main body of the image forming apparatus. Maintenance and management of the forming apparatus becomes easy.

  In the electrophotographic cartridge using the above electrophotographic photosensitive member, even when the electrophotographic photosensitive member is repeatedly used for image formation, the initial potential can be reduced little and the physical resistance is also improved. It can be good. Therefore, the electrophotographic cartridge of the present invention can be suitably used for an image forming apparatus as described in “B. Image Forming Apparatus”. In such an image forming apparatus, a stable and high-quality image can be obtained. Formation is possible.

  Hereinafter, the present invention will be described by way of examples. The examples are given for the purpose of illustrating the present invention in detail, and are not limited to the examples unless they are contrary to the gist of the present invention. In Examples and Comparative Examples, the part means “part by weight”.

<Example 1>
(Formation of undercoat layer)
A dispersion for undercoat layer was produced as follows. That is, a rutile type titanium oxide having an average primary particle size of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by weight of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) with respect to the titanium oxide were flowed at high speed. In a mixed solvent of methanol / 1-propanol in a mixed solvent of methanol / 1-propanol, which was 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 ε-caprolactam [compound represented by the following formula (A)] / bis (4-amino-3-methylcyclohexyl) methane [the following formula (B Compound represented by the following formula (C)] / decamethylene dicarboxylic acid [compound represented by the following formula (D)] / octadecamethylene dicarboxylic acid [in the following formula (E) The compositional molar ratio of the compound represented] is 60% / 15% / 5% / 15% / 5% of the copolymerized polyamide pellets with heating and stirring and mixing to dissolve the polyamide pellets. By performing sonic dispersion treatment, the weight ratio of methanol / 1-propanol / toluene is 7/1/2, and the hydrophobically treated titanium oxide / co-polymer is mixed. Containing a slip polyamide in a weight ratio of 3/1, and a solid concentration of 18.0% of the undercoat layer dispersion.

このようにして得られた下引き層形成用塗布液を、表面にアルミ蒸着したポリエチレンテレフタレートシート上に、乾燥後の膜厚が１．２μｍになるようにワイアバーで塗布、乾燥して下引き層を設けた。

The undercoat layer-forming coating solution thus obtained was applied onto a polyethylene terephthalate sheet having aluminum deposited on the surface with a wire bar so that the film thickness after drying was 1.2 μm, and dried. Was provided.

(Formation of photosensitive layer)
Next, 10 parts of oxytitanium phthalocyanine having a powder X-ray diffraction spectrum shown in FIG. 2, which shows a strong diffraction peak at a Bragg angle (2θ ± 0.2) of 27.3 ° in X-ray diffraction by CuKα ray, In addition to 150 parts of 2-dimethoxyethane, pulverization and dispersion treatment was performed with a sand grind mill to prepare a pigment dispersion. 160 parts of the pigment dispersion thus obtained were mixed with 100 parts of a 5 wt% 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 dispersion having a solid concentration of 4.0% by weight.
The dispersion was applied on the 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, 50 parts of a charge transport material comprising a composition of geometric isomers represented by the structure represented by the following formula (a) shown in JP-A-2002-80432, represented by the following formula (b): 100 parts of a polyester resin having a repeating structure, 8 parts of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate (trade name Irganox 1076, manufactured by Ciba Geigy Co.) as an antioxidant, and As a leveling agent, 0.05 part of silicone oil was mixed with 640 parts of a mixed solvent of tetrahydrofuran and toluene (80% by weight of tetrahydrofuran, 20% by weight of toluene) to prepare a coating solution for forming a charge transport layer.

  This charge transport layer forming coating solution is applied onto the charge generation layer using an applicator, left in a room at room temperature of 25 ° C. and a relative humidity of 50% for 15 minutes, and then heated in a hot air dryer (TABAI ESPEC set at 110 ° C. The product is placed in a chamber of model PH101) and held for 20 minutes, then the set temperature in the store is set to 125 ° C, raised to the set temperature over 4 minutes, and held for 20 minutes in an atmosphere at a set temperature of 125 ° C. Then, the charge transport layer was dried to prepare an electrophotographic photoreceptor A. The film thickness of the charge transport layer after drying was 25 μm.

<Example 2>
After applying the coating solution for forming the charge transport layer using an applicator, put it in a hot air dryer set at 90 ° C. and hold it for 20 minutes, then inside the hot air dryer set at 125 ° C. prepared separately The charge transport layer was dried in the same manner as in Example 1 except that the electrophotographic photosensitive member B was prepared except that the electrophotographic photosensitive member B was dried.

<Example 3>
After applying the charge transport layer forming coating solution using an applicator, leave it in a room with a room temperature of 25 ° C. and a relative humidity of 50% for 25 minutes, and then put it in a hot air dryer set at 65 ° C. and hold it for 10 minutes. Then, the set temperature in the chamber is set to 90 ° C., the temperature is raised to the set temperature over 2 minutes, held for 20 minutes in an atmosphere at the set temperature of 90 ° C., and the set temperature in the store is set to 125 ° C. for 3 minutes. The temperature was raised to the set temperature and held for 24 minutes in an atmosphere at a set temperature of 125 ° C., and the charge transport layer was dried to produce an electrophotographic photoreceptor C. The film thickness of the charge transport layer after drying was 25 μm.

<Comparative Example 1>
Except that the charge transport layer forming coating solution was applied using an applicator, then placed in a hot air dryer set at 125 ° C. and held for 20 minutes to dry the charge transport layer, as in Example 1. The charge transport layer was dried to produce an electrophotographic photoreceptor D.

<Example 4>
A charge transport material represented by the following formula (c) was used in place of the charge transport material composed of a composition of geometric isomers represented by the structure represented by the formula (a) used in Example 2. In the same manner as in Example 2, an electrophotographic photoreceptor E was produced.

<Comparative example 2>
The same procedure as in Example 4 was applied except that the charge transport layer forming coating solution was applied using an applicator, then placed in a hot air dryer set at 125 ° C. and held for 20 minutes to dry the charge transport layer. Thus, an electrophotographic photoreceptor F was produced.

<Reference Example 1>
An electrophotographic photosensitive member G was obtained in the same manner as in Example 2 except that a polycarbonate resin having a repeating structure represented by the following formula (d) was used instead of the polyester resin used in Example 2. .

<Reference Example 2>
Similar to Reference Example 1, except that the charge transport layer forming coating solution was applied using an applicator, then placed in a hot air dryer set at 125 ° C. and held for 20 minutes to dry the charge transport layer. The charge transport layer was dried to produce an electrophotographic photoreceptor H.

<Characteristic evaluation of electrophotographic photoreceptor>
Each of the obtained electrophotographic photoreceptors A to H is mounted on an electrophotographic characteristic evaluation apparatus (manufactured by Mitsubishi Chemical Corporation) manufactured according to the electrophotographic society measurement standard, and depends on the cycle of charging, exposure, potential measurement, and static elimination. Electrical characteristics were evaluated. The results are shown in Table 1 below.
Each electrophotographic photosensitive member was attached to an aluminum drum having an outer diameter of 80 mm, and the aluminum drum and the aluminum vapor deposition layer of the electrophotographic photosensitive member were electrically connected to each other and rotated at a constant speed of 60 rpm. In an environment where the temperature is 25 ° C. and the humidity is 50%, the electrophotographic photosensitive member is charged so that the initial surface potential is −700 V, and the exposure is performed using a halogen lamp light converted to a monochromatic light of 780 nm by an interference filter. The exposure amount (hereinafter sometimes referred to as sensitivity) at which the surface potential was −350 V and the surface potential (hereinafter referred to as VL) when exposed at a light amount of 1.0 μJ / cm ² were determined.
The sensitivity is an exposure amount necessary for the surface potential to be ½ of the initial potential, and the smaller the numerical value, the higher the sensitivity. Further, VL is a potential after exposure, and a smaller value is excellent in electrical characteristics. The time from exposure to potential measurement was 100 milliseconds.

  In order to clarify the effect of the present invention, the charge transport layer forming coating solutions are the same and the drying conditions are different from each other. The change in sensitivity and the change in VL are shown in Table 2 below. . For both sensitivity change and VL change, the value of the evaluation result of the electrophotographic photosensitive member (Example) of the present invention was subtracted from the value of the evaluation result of the electrophotographic photosensitive member (Comparative Example 1) outside the present invention. In Reference Example 1, a value obtained by subtracting the value of the result of Reference Example 1 from the value of the result of Reference Example 2 is shown.

  As shown in Table 2, both sensitivity and VL are remarkably preferable by drying under a plurality of temperature conditions, and are bound by a polycarbonate resin and contain a polyester resin. It can be seen that the electrophotographic photosensitive member that does not undergo almost no change in electrical characteristics or slightly deteriorates the sensitivity even when dried under a plurality of temperature conditions.

  Next, the produced electrophotographic photosensitive member was cut into a circle having a diameter of 10 cm and subjected to wear evaluation by a Taber abrasion tester (manufactured by Taber). Test condition is to compare the weight before and after the test after 1000 rotations without wear (self-weight of wear wheel) using wear wheel CS-10F in atmosphere of room temperature 23 ° C and relative humidity 50%. It was measured by. These results are shown in Table 3.

  As shown in Table 3, there was no significant change in the mechanical strength of the photosensitive layer due to drying under a plurality of temperature conditions, and the electrophotographic photoreceptor using the polyester resin had very good wear resistance. . According to the present invention, it can be seen that the electrical characteristics represented by sensitivity and VL can be made particularly excellent while having high wear resistance.

<Example 5>
Next, the surface of a cylinder made of an aluminum alloy having a mirror-finished outer diameter of 30 mm, a length of 375.8 mm, and a thickness of 1.0 mm is anodized, and then sealed with nickel acetate as a main component. By performing sealing treatment with a pore agent, an anodic oxide film having a thickness of about 6 μm was formed.
Next, the charge generation layer coating solution used in Example 1 is dip coated with the anodized aluminum cylinder, and the charge generation layer is prepared so that the film thickness after drying at room temperature is 0.6 μm. The charge transport layer coating solution used in Example 1 was similarly dip coated on this charge generation layer. The cylinder after coating is left in a room with a room temperature of 25 ° C. and a relative humidity of 50% for 15 minutes, and then placed in a hot air dryer (TABAI ESPEC, model PH101) set at 65 ° C. and held for 10 minutes. After that, the set temperature in the chamber is raised to 90 ° C. over 2 minutes and raised to the set temperature, held for 20 minutes in an atmosphere at the set temperature of 90 ° C., and the set temperature in the chamber is set to 125 ° C. over 3 minutes. The temperature was raised to a temperature, and the charge transport layer was dried under an atmosphere having a set temperature of 125 ° C. for 24 minutes to prepare an electrophotographic photoreceptor I. The film thickness of the charge transport layer after drying was 25 μm.

<Comparative Example 3>
After dip-coating the coating solution for forming the charge transport layer, it is left in a room with a room temperature of 25 ° C. and a relative humidity of 50% for 20 minutes, and then placed in a hot air dryer set at 125 ° C. and held for 25 minutes to transport the charge. Except that the layer was dried, the charge transport layer was dried in the same manner as in Example 5 to prepare an electrophotographic photoreceptor J. The film thickness of the charge transport layer after drying was 25 μm. The electrophotographic photoreceptors I and J obtained above were subjected to the following electrical property test 2 and actual machine evaluation.

<Electrical property test 2>
Attached to an electrophotographic characteristic evaluation apparatus manufactured according to the Electrophotographic Society measurement standard (basic and applied electrophotographic technology, edited by Electrophotographic Society, Corona, page 404-405), and charged and exposed according to the following procedures. The electrical characteristics were evaluated by the cycle of potential measurement and static elimination.
Irradiation energy (when the surface potential is -350 V by irradiating the electrophotographic photosensitive member so that the initial surface potential is -700 V and irradiating the halogen lamp with 780 nm monochromatic light by an interference filter) μJ / cm ² ) was taken as the sensitivity. Further, the surface potential after exposure (−V) when exposed at 2.0 μJ / cm ² was defined as VL. In measuring the sensitivity and VL, the time required from the exposure to the potential measurement was 100 ms. The measurement environment was a temperature of 25 ° C. and a relative humidity of 50%. These results are shown in Table 4.

  From this result, it was found that the electrophotographic photoreceptor I of Example 5 showed better electrical characteristics than the electrophotographic photoreceptor J.

<Evaluation of actual machine>
The produced electrophotographic photoreceptors I and J were mounted on a black drum cartridge of a commercially available tandem type color printer (Microline Pro 9800PS-E manufactured by Oki Data Co., Ltd.) compatible with A3 printing, and mounted on the printer.
Specifications of MICROLINE Pro 9800PS-E · 4 tandem · Color 36ppm, Monochrome 40ppm
・ 1200 dpi
-DC contact roller charging-Writing with LED-With static elimination light-Polymerized toner Next, connecting a personal computer to this printer, inputting a black and white image, and confirming the output printout image, the electrophotographic image of Example 5 The photoreceptor I obtained an image having a good density. On the other hand, when the electrophotographic photosensitive member J of Comparative Example 3 was mounted, an image having an insufficient contrast and an image quality lower than that of an image formed using the electrophotographic photosensitive member I was obtained.

<Example 6>
In Example 1, instead of the polyester resin used in the charge transport layer forming coating solution, the same operation as in Example 1 was performed except that the polyester resin e represented by the following structural formula was used. Photoconductor K was obtained.

<Comparative example 4>
Except for changing the drying conditions of the coating solution for forming the charge transport layer in Example 6 into a hot air dryer (model PH101) manufactured by TABI ESPEC in an atmosphere of 125 ° C. and drying for 20 minutes, all are the same as in Example 6. Then, an electrophotographic photosensitive member L was produced.

The electrophotographic photoreceptors K and L were evaluated in the same manner as in Example 1 above. Table 5 below shows each sensitivity and VL.

  Next, the electrophotographic photoreceptors K and L were cut into a circle having a diameter of 10 cm and subjected to wear evaluation with a Taber abrasion tester (manufactured by Taber). Test conditions were measured by comparing the weight before and after the test with 1000 wheels without load (the weight of the wear wheel) under the atmosphere of 23 ° C. and 50% RH without load (self weight of the wear wheel). did. Table 6 shows these results (the amount of wear in the Taber abrasion test).

  From these results, it was found that the electrophotographic photosensitive member K of Example 6 showed better electrical characteristics than the electrophotographic photosensitive member L of Comparative Example 4.

  The electrophotographic photosensitive member of the present invention is less likely to decrease the initial voltage when repeatedly used, and has high mechanical strength and can stably form a high-quality image even when the photosensitive cycle is repeated. Therefore, the present invention can be suitably used in the fields of copiers, printers, printing machines, and the like.

1 is a schematic diagram illustrating a main configuration of an embodiment of an image forming apparatus of the present invention. It is an X-ray diffraction diagram showing a powder X-ray diffraction spectrum of oxytitanium phthalocyanine used in Examples and Comparative Examples of the present invention.

Explanation of symbols

1 Electrophotographic photoreceptor 2 Charging device (charging roller)
DESCRIPTION OF SYMBOLS 3 Exposure apparatus 4 Developing apparatus 5 Transfer apparatus 6 Cleaning apparatus 7 Fixing apparatus 41 Developing tank 42 Agitator 43 Supply roller 44 Developing roller 45 Control member 71 Upper fixing member (fixing roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper

Claims (5)

In the method for producing an electrophotographic photosensitive member having a photosensitive layer including a polyester-containing layer formed by applying a coating solution containing a polyester resin on a conductive support,
A method for producing an electrophotographic photoreceptor, comprising drying a coating film coated with the coating solution under a plurality of temperature conditions when forming the polyester-containing layer. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the polyester resin has a repeating structure represented by the following formula (1).

(In Formula (1), Ar ¹ and Ar ² represent an arylene group which may have a substituent, and X ¹ and Y ¹ represent a divalent linking group.) An electrophotographic photosensitive member produced by the method for producing an electrophotographic photosensitive member according to claim 1. An electrophotographic photosensitive member produced by the method for producing an electrophotographic photosensitive member according to claim 1 or 2,
Charging means for charging the electrophotographic photosensitive member, image exposing means for performing image exposure on the charged electrophotographic photosensitive member to form an electrostatic latent image, developing means for developing the electrostatic latent image with toner, the toner At least one selected from transfer means for transferring the toner to the transfer body, fixing means for fixing the toner transferred to the transfer body, and cleaning means for recovering the toner attached to the electrophotographic photoreceptor. An electrophotographic cartridge characterized by the above. An electrophotographic photosensitive member produced by the method for producing an electrophotographic photosensitive member according to claim 1 or 2,
Charging means for charging the electrophotographic photosensitive member;
Image exposing means for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image;
Developing means for developing the electrostatic latent image with toner;
An image forming apparatus comprising: a transfer unit that transfers the toner to a transfer target.

Images