JP2006145870A - Electrophotographic photoreceptor, electrophotographic photoreceptor cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the residual potential of an electrophotographic photoreceptor and to heighten the sensitivity. <P>SOLUTION: A hydrazone compound of formula (1) and a benzidine derivative of formula (2) are incorporated into a photosensitive layer of the electrophotographic photoreceptor. In the formula (1), R<SP>1</SP>and R<SP>2</SP>each independently represent an organic group; Ar<SP>1</SP>and Ar<SP>2</SP>each independently represent aryl; Ar<SP>3</SP>represents arylene; and m and n each represent an integer satisfying 0≤m≤5, 0≤n≤5 and 1≤m+n. In the formula (2), Ar<SP>4</SP>-Ar<SP>7</SP>each independently represent aryl. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrophotographic photosensitive member having a photosensitive layer formed on a conductive support, and an electrophotographic photosensitive member cartridge and an image forming apparatus using the same.

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

  Organic photoconductive materials have been actively developed for the purpose of increasing the sensitivity of electrophotographic photoreceptors and various techniques have been proposed. For example, Patent Documents 1 to 6 describe a technique in which a hydrazone compound or a benzidine derivative is used as an organic photoconductive material, and this photoconductive material is contained in a photosensitive layer of an electrophotographic photosensitive member.

JP-A-62-112164 JP-A-6-161135 Japanese Patent Laid-Open No. 5-80552 JP 2000-56490 A JP-A-5-204170 JP 2004-45909 A

However, since the electrophotographic photosensitive member using the conventional technique including those described in Patent Documents 1 to 6 has a problem that the residual potential is large, the quality of an image formed using the electrophotographic photosensitive member is reduced. There was room for improvement.
The present invention has been made in view of the above problems, and provides an electrophotographic photosensitive member having high sensitivity and a small residual potential, and an electrophotographic photosensitive member cartridge and an image forming apparatus using the same. The purpose is to provide.

  The inventor of the present invention has a specific structure as at least one of a hydrazone compound having a hydrazone skeleton and a benzidine derivative having a benzidine skeleton when a known hydrazone compound and a benzidine derivative are used in combination as a material for a photosensitive layer. In other words, specifically, the hydrazone compound has two phenyl groups bonded to nitrogen at the terminal on the carbonyl compound side, and at least one organic group is present on one or both of the phenyl groups. By using a substituted hydrazone compound or a tetraphenylbenzidine derivative having four or more substituents as the benzidine derivative, it is possible to increase the sensitivity of the electrophotographic photoreceptor and reduce the residual potential. Find out what you can do, Invention was allowed to complete. Here, the carbonyl compound side of the hydrazone compound is the side opposite to the hydrazine-derived nitrogen-nitrogen bond at the carbon-nitrogen double bond of the hydrazone skeleton {for example, the left side in the following formula (1)}. Represents.

  That is, the gist of the present invention resides in an electrophotographic photosensitive member comprising a photosensitive layer containing a hydrazone compound represented by the following formula (1) and a benzidine derivative represented by the following formula (2). . Thereby, the sensitivity of the electrophotographic photosensitive member can be increased and the residual potential can be reduced.

｛式（１）において、Ｒ¹及びＲ²はそれぞれ独立に有機基を表わす。また、Ａｒ¹及びＡｒ²はそれぞれ独立にアリール基を表わす。さらに、Ａｒ³はアリーレン基を表わす。また、ｍ及びｎはそれぞれ０≦ｍ≦５、０≦ｎ≦５、１≦ｍ＋ｎを満たす整数を表わす。｝

{In Formula (1), R ¹ and R ² each independently represents an organic group. Ar ¹ and Ar ² each independently represents an aryl group. Ar ³ represents an arylene group. M and n represent integers satisfying 0 ≦ m ≦ 5, 0 ≦ n ≦ 5, and 1 ≦ m + n, respectively. }

｛式（２）において、Ａｒ⁴〜Ａｒ⁷はそれぞれ独立にアリール基を表わす。｝

{In Formula (2), Ar ^{4 to} Ar ⁷ each independently represents an aryl group. }

  Another gist of the present invention is an electrophotographic photoreceptor comprising a photosensitive layer containing a hydrazone compound of the following formula (3) and a tetraphenylbenzidine derivative having 4 or more substituents. (Claim 2). This also increases the sensitivity of the electrophotographic photosensitive member and reduces the residual potential.

｛式（３）において、Ａｒ⁸〜Ａｒ¹¹はそれぞれ独立にアリール基を表わす。また、Ａｒ¹²はアリーレン基を表わす。｝

{In Formula (3), Ar < ⁸ > -Ar < ¹¹ > represents an aryl group each independently. Ar ¹² represents an arylene group. }

  In this case, the electrophotographic photoreceptor preferably contains oxytitanium phthalocyanine having a diffraction peak at 27.3 ° in a Bragg angle (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction. ). Since this oxytitanium phthalocyanine can be used as a charge generation material having very high charge generation efficiency, it is possible to increase the sensitivity of the electrophotographic photosensitive member.

  Still another subject matter of the present invention is the above-described electrophotographic photosensitive member, a charging unit that charges the electrophotographic photosensitive member, an exposure unit that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image, At least one of a developing unit that develops an electrostatic latent image formed on the electrophotographic photosensitive member and a cleaning unit that removes the developer from the electrophotographic photosensitive member is provided. It exists in an electrophotographic photosensitive member cartridge (claim 4).

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

  According to the electrophotographic photosensitive member of the present invention, it is possible to increase the sensitivity of the electrophotographic photosensitive member and reduce the residual potential. Further, according to the electrophotographic photosensitive member cartridge and the image forming apparatus of the present invention using the same, the image quality can be improved.

  Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described below, and can be arbitrarily modified without departing from the gist of the present invention. .

[I. Electrophotographic photoreceptor]
The electrophotographic photoreceptor of the present invention (hereinafter appropriately referred to as “the photoreceptor of the present invention”) is provided with a photosensitive layer containing a specific hydrazone compound and a specific benzidine derivative as charge transport materials.

[1. Charge transport material]
The photoreceptor of the present invention includes at least a charge transport material (hereinafter referred to as “first charge transport material” as appropriate) composed of a hydrazone compound represented by the following formula (1) and a benzidine derivative represented by the following formula (2): One or both of charge transport materials (hereinafter referred to as “second charge transport materials” as appropriate) comprising a hydrazone compound of the formula (3) and a tetraphenylbenzidine derivative having four or more substituents are used as the photosensitive layer. Contains in.

｛式（１）において、Ｒ¹及びＲ²はそれぞれ独立に有機基を表わす。また、Ａｒ¹及びＡｒ²はそれぞれ独立にアリール基を表わす。さらに、Ａｒ³はアリーレン基を表わす。また、ｍ及びｎはそれぞれ０≦ｍ≦５、０≦ｎ≦５、１≦ｍ＋ｎを満たす整数を表わす。｝

{In Formula (1), R ¹ and R ² each independently represents an organic group. Ar ¹ and Ar ² each independently represents an aryl group. Ar ³ represents an arylene group. M and n represent integers satisfying 0 ≦ m ≦ 5, 0 ≦ n ≦ 5, and 1 ≦ m + n, respectively. }

｛式（２）において、Ａｒ⁴〜Ａｒ⁷はそれぞれ独立にアリール基を表わす。｝

{In Formula (2), Ar ^{4 to} Ar ⁷ each independently represents an aryl group. }

｛式（３）において、Ａｒ⁸〜Ａｒ¹¹はそれぞれ独立にアリール基を表わす。また、Ａｒ¹²はアリーレン基を表わす。｝

{In Formula (3), Ar < ⁸ > -Ar < ¹¹ > represents an aryl group each independently. Ar ¹² represents an arylene group. }

[1-1. First charge transport material]
The first charge transport material includes a hydrazone compound of the above formula (1) and a benzidine derivative of the above formula (2). Note that the hydrazone compound of the above formula (1) and the benzidine derivative of the above formula (2) are known, respectively. As the hydrazone compound, 2 bonded to nitrogen at the terminal on the carbonyl compound side as in the formula (1) When a hydrazone compound having two phenyl groups and at least one organic group substituted on one or both of the phenyl groups is used in combination with the photosensitive layer, the sensitivity of the photoreceptor is increased and the residual The advantage that the potential can be reduced can be obtained.

First, the hydrazone compound represented by the above formula (1) will be described.
In the above formula (1), R ¹ and R ² each independently represents an organic group. The organic group is not particularly limited, and any organic group can be used as long as the effects of the present invention are not hindered. Usually, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, or the like is used.

The number of carbon atoms of the alkyl group that can be used as R ¹ and R ² is arbitrary, but it is usually 1 or more, usually 6 or less, preferably 3 or less. If the upper limit of this range is exceeded, the electrical characteristics of the photoreceptor of the present invention may be deteriorated.
The alkyl group used as R ¹ and R ² may be linear, branched or cyclic. Specific examples include linear alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group and hexyl group, branching such as isopropyl group, isobutyl group, sec-butyl group, and tert-butyl group. Examples thereof include a cyclic alkyl group such as a chain alkyl group and a cyclohexyl group. Among these, a linear alkyl group is preferable, and a methyl group is particularly preferable.

Furthermore, the carbon number of the alkoxy group that can be used as R ¹ and R ² is arbitrary, but it is usually 1 or more, usually 6 or less, preferably 3 or less. If the upper limit of this range is exceeded, the electrical characteristics of the photoreceptor of the present invention may be deteriorated.
Further, the alkoxy group used as R ¹ and R ² may be linear, branched or cyclic. Specific examples thereof include an alkoxy group obtained by bonding oxygen to the groups exemplified in the specific examples of the alkyl group as R ¹ and R ² . Among these, a linear alkoxy group is preferable, and a methoxy group is particularly preferable.

Furthermore, the number of rings of the aryl group that can be used as R ¹ and R ² is not limited, but is usually 4 or less, preferably 2 or less. If the upper limit of this range is exceeded, the stability of the hydrazone compound represented by formula (1) may be reduced.
The number of carbon atoms of the aryl group that can be used as R ¹ and R ² is arbitrary, but it is usually 6 or more, and usually 16 or less, preferably 10 or less. If the upper limit of this range is exceeded, the stability of the hydrazone compound represented by formula (1) may be reduced.
Specific examples of the aryl group used as R ¹ and R ² include a phenyl group and a naphthyl group. Of these, a phenyl group is preferred.

Further, the number of rings of the aryloxy group that can be used as R ¹ and R ² is not limited, but is usually 4 or less, preferably 2 or less. If the upper limit of this range is exceeded, the electrical characteristics of the photoreceptor of the present invention may be deteriorated.
The number of carbon atoms of the aryloxy group that can be used as R ¹ and R ² is arbitrary, but it is usually 6 or more, and usually 16 or less, preferably 10 or less. If the upper limit of this range is exceeded, the electrical characteristics of the photoreceptor of the present invention may be deteriorated.
Specific examples of the aryloxy group used as R ¹ and R ² include an aryloxy group obtained by bonding oxygen to the groups exemplified as specific examples of the aryl group.

Furthermore, the organic groups used as R ¹ and R ² may each independently have any substituent unless it is contrary to the gist of the present invention. The number of substituents is arbitrary, and the substituents may be bonded to form a ring. Examples of the substituent include an organic group, and specific examples include an alkyl group such as a methyl group, an ethyl group, a propyl group, and an isopropyl group, an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, and an isopropoxy group, An aryl group such as a phenyl group and a naphthyl group can be mentioned. Further, halogen groups such as fluorine atom, chlorine atom, bromine atom and iodine atom, nitro group, amino group and the like may be used as a substituent.
R ¹ and R ² may be independently bonded to any position among the ortho, meta and para positions of the benzene ring to be bonded, but the para position is usually preferred.

  Further, in the above formula (1), m and n represent integers satisfying 0 ≦ m ≦ 5, 0 ≦ n ≦ 5, and 1 ≦ m + n, respectively. Among these, m and n are preferably m ≧ 1 and n ≧ 1 and further satisfy 2 ≦ m + n ≦ 4 in terms of electrical characteristics of the photoreceptor of the present invention.

In the above formula (1), Ar ¹ and Ar ² each independently represents an aryl group. The number of rings that the aryl group has is not limited, but is usually 4 or less, preferably 2 or less. If the upper limit of this range is exceeded, production may become difficult.
Furthermore, the carbon number of the aryl group that can be used as Ar ¹ and Ar ² is arbitrary, but it is usually 6 or more, and usually 16 or less, preferably 10 or less. If the upper limit of this range is exceeded, production may become difficult.

Specific examples of the aryl group used as Ar ¹ and Ar ² include a phenyl group, a naphthyl group, and a pyrenyl group.
Furthermore, the aryl groups used as Ar ¹ and Ar ² may each independently have any substituent unless it is contrary to the spirit of the present invention. The number of substituents is arbitrary, and the substituents may be bonded to form a ring. Examples of the substituent include an organic group, and specific examples include an alkyl group such as a methyl group, an ethyl group, a propyl group, and an isopropyl group, an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, and an isopropoxy group, An aryl group such as a phenyl group and a naphthyl group can be mentioned. Further, halogen groups such as fluorine atom, chlorine atom, bromine atom and iodine atom, nitro group, amino group and the like may be used as a substituent.

In the above formula (1), Ar ³ represents an arylene group. Although there is no restriction | limiting in the number of the rings which this arylene group has, Usually, 4 or less, Preferably it is 2 or less. If the upper limit of this range is exceeded, the stability of the hydrazone compound represented by formula (1) may be reduced.
Furthermore, although the number of carbon atoms of the arylene group that can be used as Ar ³ is arbitrary, it is usually 6 or more, and usually 16 or less, preferably 10 or less. If the upper limit of this range is exceeded, the stability of the hydrazone compound represented by formula (1) may be reduced.
Specific examples of the arylene group used as Ar ³ include a phenylene group and a naphthylene group. Of these, a phenylene group is preferable.

Furthermore, the arylene group used as Ar ³ may have an arbitrary substituent as long as it is not contrary to the gist of the present invention, the number of substituents is arbitrary, and the substituents are bonded to each other to form a ring. It may be formed. Specific examples of the substituent include the same substituents that the aryl group used as Ar ¹ and Ar ² may have.
In the first charge transport material, one hydrazone compound represented by the above formula (1) may be used alone, or two or more hydrazone compounds may be used in any combination and ratio.

Next, the benzidine derivative represented by the above formula (2) will be described.
In the above formula (2), Ar ^{4 to} Ar ⁷ each independently represents an aryl group. The number of rings that the aryl group has is not limited, but is usually 4 or less, preferably 2 or less. If the upper limit of this range is exceeded, the benzidine derivative represented by the formula (2) may not be dissolved in the organic solvent used as the solvent for the coating solution when the photosensitive layer is produced.
Furthermore, although the carbon number of the aryl group that can be used as Ar ^{4 to} Ar ⁷ is arbitrary, it is usually preferably 6 or more and usually 16 or less, and particularly preferably those having 6 carbon atoms. If the upper limit of this range is exceeded, the benzidine derivative represented by the formula (2) may not be dissolved in the organic solvent used as the solvent for the coating solution when the photosensitive layer is produced.

Specific examples of the aryl group used as Ar ^{4 to} Ar ⁷ include a phenyl group and a naphthyl group. Of these, a phenyl group is preferred.
Furthermore, the aryl group used as Ar ^{4 to} Ar ⁷ may have an arbitrary substituent unless it is contrary to the gist of the present invention. The number of substituents is arbitrary, and the substituents may be bonded to form a ring. Examples of substituents include organic groups. Specific examples include alkyl groups such as methyl, ethyl, propyl, and isopropyl groups, alkoxy groups such as methoxy, ethoxy, propoxy, and isopropoxy groups. And aryl groups such as a group, a phenyl group and a naphthyl group.

However, the benzidine derivative represented by the above formula (2) is preferably a tetraphenylbenzidine derivative represented by the following formula (4).

In the above formula (4), R ^{3 to} R ⁶ each independently represents an alkyl group or an alkoxy group. Furthermore, when each of R ^{3 to} R ⁶ is 2 or more, they may be bonded to each other to form a ring.
When R ^{3 to} R ⁶ are alkyl groups, the number of carbon atoms is arbitrary, but usually 1 or more, usually 10 or less, preferably 4 or less is desirable, and among these, 1 is particularly preferable. If the upper limit of this range is exceeded, the charge mobility of the photosensitive layer of the photoreceptor of the present invention may be reduced. In addition, by setting the carbon number within the above range, it is possible to improve the electrical characteristics of the photoreceptor of the present invention, and the tetraphenylbenzidine derivative represented by the formula (4) is used as a coating solution at the time of preparing the photosensitive layer. It can be easily dissolved in the solvent used.
Specific examples of the alkyl group used as R ^{3 to} R ⁶ include a straight chain alkyl group such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, isopropyl group, isobutyl group, sec- Examples thereof include branched alkyl groups such as butyl group and tert-butyl group, and cycloalkyl groups such as cyclohexyl group.

In addition, when R ^{3 to} R ⁶ are alkoxy groups, the number of carbon atoms is arbitrary, but it is usually 1 or more, usually 10 or less, preferably 4 or less. If the upper limit of this range is exceeded, the charge mobility of the photosensitive layer of the photoreceptor of the present invention may be reduced. In addition, by setting the carbon number within the above range, it is possible to improve the electrical characteristics of the photoreceptor of the present invention, and the tetraphenylbenzidine derivative represented by the formula (4) is used as a coating solution at the time of preparing the photosensitive layer. It can be easily dissolved in the solvent used.
Specific examples of the alkoxy group used as R ^{3 to} R ⁶ include an alkoxy group obtained by bonding an oxygen atom to the groups exemplified as specific examples of the alkyl group used as R ^{3 to} R ⁶ .

Further, in the above formula _(4), n ₁ ~n 4 independently represent 1 or 2. Among them, it is preferable that at least one of n _{1 to} n ₄ is 1.
R ^{3 to} R ⁶ may be independently bonded to any position among the ortho, meta and para positions of the benzene ring to be bonded.
In the first charge transport material, the benzidine derivative of the above formula (2) and the tetraphenylbenzidine derivative of the formula (4) may be used alone, or two or more thereof may be used in any combination and ratio. You may use together.

  The ratio of the hydrazone compound of the above formula (1) and the benzidine derivative of the above formula (2) used in combination in the first charge transport material is not limited and is arbitrary, but “the hydrazone compound of the formula (1) "Weight" / "Weight of benzidine derivative of formula (2)" is usually 5/95 or more, preferably 25/75 or more, and usually 75/25 or less, preferably 50/50 or less. In the description of this range, the fact that the weight of the hydrazone compound of the formula (1) is large is referred to as “above”, and the fact that the weight of the hydrazone compound of the formula (1) is small is expressed as “below”. Below the above range, there is a risk that defects such as memory may occur when image formation is performed by the image forming apparatus using the photoreceptor of the present invention, and when it exceeds, the charge transport material may be deposited from the photoreceptor of the present invention. This is because there is a risk that the electrical characteristics may deteriorate during repeated use of the photoreceptor of the present invention. When two or more hydrazone compounds and benzidine derivatives are used in combination, it is desirable that the total ratio of the hydrazone compound and the benzidine derivative be within the above range.

[1-2. Second charge transport material]
The second charge transport material includes the hydrazone compound of the above formula (3) and a tetraphenylbenzidine derivative having four or more substituents. The hydrazone compound of the above formula (3) and the tetraphenylbenzidine derivative having 4 or more substituents are known, respectively, but by using these together in the photosensitive layer, the sensitivity of the photoreceptor is increased. In addition, the advantage that the residual potential can be reduced can be obtained.

First, the hydrazone compound represented by the above formula (3) will be described.
In the above formula (3), Ar ^{8 to} Ar ¹¹ each independently represents an aryl group. There is no restriction | limiting in particular in this aryl group, Arbitrary aryl groups can be used.

The number of rings of the aryl group that can be used as Ar ^{8 to} Ar ¹¹ is arbitrary, but usually 1 or more and usually 4 or less are desirable, and those having 1 ring are particularly preferable. If the upper limit of this range is exceeded, the stability of the hydrazone compound represented by formula (3) may be reduced.
Furthermore, the number of carbon atoms of the aryl group that can be used as Ar ^{8 to} Ar ¹¹ is arbitrary, but usually 6 or more, and usually 16 or less is preferable, and among them, those having 6 carbon atoms are particularly preferable. If the upper limit of this range is exceeded, the stability of the hydrazone compound represented by formula (3) may be reduced.
Specific examples of the aryl group used as Ar ^{8 to} Ar ¹¹ include a phenyl group and a naphthyl group. Of these, a phenyl group is preferred.

Furthermore, the aryl groups used as Ar ^{8 to} Ar ¹¹ may each independently have any substituent unless it is contrary to the spirit of the present invention. The number of substituents is arbitrary, and the substituents may be bonded to form a ring.
Examples of the substituent include an organic group, and specific examples include an alkyl group such as a methyl group, an ethyl group, a propyl group, and an isopropyl group, an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, and an isopropoxy group, An aryl group such as a phenyl group and a naphthyl group can be mentioned. Further, halogen groups such as fluorine atom, chlorine atom, bromine atom and iodine atom, nitro group, amino group and the like may be used as a substituent.

In the above formula (3), Ar ¹² represents an arylene group. Although there is no restriction | limiting in the number of the rings which this arylene group has, Usually, 4 or less, Preferably it is 2 or less. If the upper limit of this range is exceeded, the stability of the hydrazone compound represented by formula (3) may be reduced.
Further, the number of carbon atoms of the arylene group that can be used as Ar ¹² is arbitrary, but usually it is preferably 6 or more and usually 16 or less, and particularly preferably 6 carbon atoms. If the upper limit of this range is exceeded, the stability of the hydrazone compound represented by formula (3) may be reduced.
Specific examples of the arylene group used as Ar ¹² include a phenylene group and a naphthylene group. Of these, a phenylene group is preferable.

Furthermore, the arylene group used as Ar ¹² may have an arbitrary substituent unless it is contrary to the gist of the present invention. The number of substituents is arbitrary, and the substituents may be bonded to form a ring. Specific examples of the substituent include the same substituents that the aryl group used as Ar ^{8 to} Ar ¹¹ may have.
In addition, the hydrazone compound represented by the said Formula (3) may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

Next, a tetraphenylbenzidine derivative used for the second charge transport material will be described.
The tetraphenylbenzidine derivative used for the second charge transport material has four or more substituents. That is, it is a derivative in which four or more substituents are substituted for the four phenyl groups and two phenylene groups of tetraphenylbenzidine.

The number of substituents substituted on tetraphenylbenzidine is not limited as long as it is 4 or more, but is usually 4 or more, preferably 5 or more, more preferably 6 or more, and usually 28 or less, preferably 12 or less. More preferably, it is 8 or less.
Moreover, substituents may combine to form a ring.
Furthermore, there is no restriction | limiting in the kind of substituent, and it is arbitrary. Examples of the substituent include an organic group, and specific examples include an alkyl group such as a methyl group, an ethyl group, a propyl group, and an isopropyl group, an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, and an isopropoxy group, An aryl group such as a phenyl group and a naphthyl group can be mentioned. Further, halogen groups such as fluorine atom, chlorine atom, bromine atom and iodine atom, nitro group, amino group and the like may be used as a substituent.

However, the tetraphenylbenzidine derivative used for the second charge transport material is preferably a tetraphenylbenzidine derivative represented by the above formula (4).
In addition, the tetraphenylbenzidine derivative used in the second charge transport material may be used alone or in combination of two or more in any combination and ratio.

  Further, the ratio of the hydrazone compound of the above formula (3) used in combination with the second charge transport material to the tetraphenylbenzidine derivative having four substituents is not limited and is arbitrary. "Weight of hydrazone compound" / "weight of tetraphenylbenzidine derivative having four substituents", usually 20/80 or more, preferably 40/60 or more, and usually 80/20 or less, preferably 60/40 or less. is there. In the description of this range, the fact that the weight of the hydrazone compound of the formula (3) is large is referred to as “above”, and the fact that the weight of the hydrazone compound of the formula (3) is small is expressed as “below”. This is because if it is below the above range, the charge transport material may be deposited from the photoreceptor of the present invention, and if it exceeds, the electrical characteristics of the photoreceptor may be deteriorated.

[1-3. Concrete example]
Specific examples of the first and second charge transport materials described above include those in which hydrazone compounds and benzidine derivatives as shown in Tables 1-1 to 1-3 below are used in combination.

[2. Structure of photoconductor]
The photoreceptor of the present invention is constituted by containing at least one of the above-described first and second charge transport materials in the photosensitive layer of any known photoreceptor. Usually, the photoconductor is configured as a photoconductive layer formed on a conductive support.

[2-1. Conductive support]
There is no particular limitation on the material of the conductive support, and any material used for a known conductive support can be used, for example, a metal material such as aluminum, aluminum alloy, stainless steel, copper, nickel, A resin material mixed with conductive powder such as metal, carbon and tin oxide, or a conductive material such as aluminum, nickel and ITO (indium tin oxide alloy) was deposited or applied on the surface. Resin, glass, paper, etc. are mentioned.
Moreover, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  Furthermore, the shape of the conductive support is also arbitrary, and for example, a drum shape, a sheet shape, a belt shape or the like is usually used. Alternatively, a conductive material made of a metal material coated with a conductive material having an appropriate resistance value may be used for controlling conductivity, surface properties, etc., or for covering defects.

Further, when a metal material such as an aluminum alloy is used as the conductive support, it may be used after anodizing. In addition, when anodizing is performed, it is desirable to perform sealing by a known method.
The anodizing treatment can be carried out by any method, but is usually carried out by energizing in an acidic bath using the conductive support as an electrode. Although there is no restriction | limiting in particular about an acidic bath, For example, acidic baths, such as chromic acid, a sulfuric acid, an oxalic acid, a boric acid, sulfamic acid, are mentioned. Of these, anodizing in sulfuric acid gives the best results.

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

  Further, it is desirable to subject the anodic oxide film thus formed to a sealing treatment. The sealing treatment can be carried out by any method, but is usually carried out by immersing the conductive support in an aqueous sealing agent solution containing a sealing agent. A typical example is a low-temperature sealing treatment in which a conductive support is immersed in a sealant aqueous solution at a low temperature, or a high-temperature sealing in which a conductive support is immersed in a sealant aqueous solution at a high temperature. Processing.

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

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

In addition, the sealing agent aqueous solution may contain substances other than the sealing agent. For example, in order to further improve the physical properties of the film, a metal salt such as cobalt fluoride, cobalt acetate, or nickel sulfate, a surfactant, or the like may be mixed in the sealing agent aqueous solution.
After performing the above process, it is washed with water and dried to finish the low temperature sealing process.

On the other hand, the high temperature sealing treatment is performed by immersing the conductive support in an aqueous sealing agent solution at a high temperature.
In the high-temperature sealing treatment, a metal salt such as nickel acetate, cobalt acetate, lead acetate, nickel acetate-cobalt, and barium nitrate can be used as the sealing agent, but usually nickel acetate is used as a main component.

At this time, the concentration of the sealing agent in the aqueous sealing agent solution used in the case of the high-temperature sealing treatment is arbitrary, but it is usually most effective to carry out in the range of 5 g / l to 20 g / l. is there.
The treatment temperature is arbitrary, but is usually 80 ° C. or higher, preferably 85 ° C. or higher, and usually 100 ° C. or lower, preferably 98 ° C. or lower, in order to smoothly proceed with the sealing treatment.

Furthermore, the pH of the aqueous sealing agent solution is also arbitrary, but is usually 5.0 or more and usually 6.0 or less. In addition, there is no restriction | limiting in the pH adjuster used when adjusting pH, Although arbitrary things can be used, For example, the thing similar to the case of a low temperature sealing process can be used.
The treatment time is also optional, but it is usually 1 minute to 3 minutes per 1 μm of the film thickness, and it is usually 10 minutes or more, preferably 15 minutes or more.
Furthermore, the treatment may be performed with high-temperature water or high-temperature steam substantially free of salts.

As in the case of the low temperature sealing treatment, the sealing agent aqueous solution may contain a substance other than the sealing agent in the high temperature sealing treatment. For example, in order to further improve the film properties, sodium acetate, organic carboxylic acid, anionic or nonionic surfactant, etc. may be mixed in the sealing agent aqueous solution.
After performing the above process, it is washed with water and dried to finish the high temperature sealing process.

  However, when the average film thickness of the coating is thick, usually, a strong sealing condition is required due to a high concentration of the sealing liquid and high temperature / long time treatment. Therefore, productivity is reduced and surface defects such as spots, dirt, and dusting are likely to occur on the coating surface. From the viewpoint of preventing such harmful effects, the average film thickness of the anodized film is usually 20 μm or less, preferably 7 μm or less.

  In addition, the surface of the conductive support may be smooth, or may be roughened by using a special cutting method or by performing a polishing process. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the support. In order to reduce the cost, it is possible to use the drawing tube as it is without performing the cutting process. In particular, when a non-cutting aluminum substrate such as drawing, impact processing, and ironing is used as a support, the above-described treatment eliminates dirt and foreign matter adhering to the surface, small scratches, and the like. This is preferable because a clean substrate can be obtained.

[2-2. Undercoat layer]
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 or a resin in which particles such as a metal oxide are dispersed is used.

  Examples of the 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, Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium titanate and barium titanate. One kind of these particles may be used alone, or two or more kinds of particles may be mixed and used in an arbitrary combination and ratio.

Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable.
The surface of the titanium oxide particles may be treated with an inorganic material such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic material such as stearic acid, polyol, or silicone. In addition, the process performed to a titanium oxide particle may be one type, and may perform two or more types of processes by arbitrary combinations and grades.

Further, as the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. In addition, the titanium oxide particles may have only one crystal type, or two or more crystal types may be included in any combination and ratio.
In addition, various particle diameters of the metal oxide particles can be used. Among them, the average primary particle diameter is usually 10 nm or more from the viewpoint of the characteristics of the binder resin as a raw material for the undercoat layer and the stability of the liquid. Further, it is usually 100 nm or less, preferably 50 nm or less.

  The undercoat layer is preferably formed in a form in which the metal oxide particles are dispersed in a binder resin. The type of binder resin used for the undercoat layer is arbitrary, but specific examples include epoxy resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, Polycarbonate resin, polyurethane resin, polyimide resin, vinylidene chloride resin, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol resin, polyacrylic acid resin, polyacrylamide resin, polyvinyl pyrrolidone resin, polyvinyl pyridine resin, water-soluble polyester Resin, cellulose ester resin such as nitrocellulose, cellulose ether resin, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, zirconium chelate compound Zirconium alkoxide compounds such as organic zirconium compounds of titanyl chelate compounds, organic titanyl compounds such as titanyl alkoxide compounds, such as known binder resin such as a silane coupling agent can be used.

  In addition, binder resin may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. Moreover, you may use with the hardening | curing form with the hardening | curing agent. Among these, alcohol-soluble copolymerized polyamide, modified polyamide, and the like are preferable because they exhibit good dispersibility and coating properties.

  The mixing ratio of the metal oxide particles to the binder resin used in the undercoat layer can be arbitrarily selected, but it is usually preferable to use in the range of 10 wt% or more and 500 wt% or less. Usually, the undercoat layer is formed by applying a dispersion obtained by dissolving or dispersing metal oxide particles and a binder resin in an appropriate solvent or dispersion medium to the support surface, and the mixing ratio is within the above range. As a result, the stability and coating properties of the dispersion can be improved. In addition, the kind of the solvent and dispersion medium used when forming the undercoat layer is arbitrary.

Furthermore, the thickness of the undercoat layer can be arbitrarily selected, but is usually 0.01 μm or more, preferably from the viewpoint of improving the photoreceptor characteristics of the photoreceptor and the coating properties of the dispersion during production. The thickness is 1 μm or more, usually 30 μm or less, preferably 20 μm or less.
The undercoat layer may contain pigment particles, resin particles, and the like for the purpose of preventing image defects.

[2-3. Photosensitive layer]
Next, the photosensitive layer formed on the conductive support (on the undercoat layer when an undercoat layer is provided) will be described.
The photosensitive layer is a layer containing at least one of the first and second charge transport materials described above. The type may be a single layer structure in which the charge generation material and the charge transport material are present in the same layer and dispersed in a binder resin (hereinafter referred to as “single layer type” as appropriate) It has a layered structure (hereinafter referred to as “laminated type” as appropriate) in which a charge generating layer in which a generating material is dispersed in a binder resin and a charge transporting layer in which a charge transporting material is dispersed in a binder resin. May be. In addition, as the laminated photosensitive layer, a charge generation layer and a charge transport layer are laminated in this order from the conductive support side, and a charge transport layer and a charge generation layer are laminated in this order. There are reverse laminated type photosensitive layers, and any of them can be adopted.

[2-3-1. Multilayer type photosensitive layer]
[I. Charge generation layer]
In the laminated photosensitive layer, the charge generation layer contains a charge generation material, and usually contains a binder resin and other components used as necessary.
Specifically, such a charge generation layer is prepared by, for example, preparing a coating solution by dissolving or dispersing a charge generation material and a binder resin in a solvent or a dispersion medium. It can be obtained by coating and drying on a charge generation layer, or in the case of a reverse lamination type photosensitive layer, on a conductive support (or on an undercoat layer when an undercoat layer is provided).

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

Among the organic pigments exemplified above, the charge generating substance is particularly preferably a phthalocyanine pigment or an azo pigment, more preferably a phthalocyanine pigment, and particularly preferably oxytitanium phthalocyanine.
Further, as oxytitanium phthalocyanine, various crystal forms can be used as well as amorphous ones. In particular, a crystalline oxytitanium phthalocyanine having a diffraction peak at a Bragg angle (2θ ± 0.2 °) of 27.3 ° in an X-ray diffraction spectrum using CuKα as a radiation source has a very high charge generation efficiency. It can be used as a charge generation material more preferably.
In addition, a charge generation material may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

There is no restriction | limiting in binder resin used for a charge generation layer, Arbitrary resin can be used. Specific examples thereof include polyacrylic acid ester, polymethacrylic acid ester, polyester, polycarbonate, polyvinyl acetal, polyvinyl acetoacetal, polyvinyl propional, polyvinyl butyral, cellulose ester, cellulose ether, vinyl chloride vinyl acetate copolymer and the like. It is done.
In addition, binder resin may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  Among these, a resin containing a hydroxyl group is excellent in dispersion stability of the charge generation material and is suitable for use as a binder resin. Examples of the resin containing a hydroxyl group include polyvinyl acetal, polyvinyl acetoacetal, polyvinyl propional, polyvinyl butyral, phenoxy resin, cellulose ester, cellulose ether, vinyl chloride vinyl acetate copolymer, and the like. Among these, polyvinyl acetals are more preferable, and polyvinyl butyral resins are particularly preferably used as the binder resin for the charge generation layer.

  Moreover, there is no restriction | limiting in particular in the solvent and dispersion medium which melt | dissolve binder resin and are used for preparation of a coating liquid, Arbitrary solvents and dispersion media can be used. Specific examples thereof include 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 and methyl ethyl ketone. , Ketones such as cyclohexanone, aromatic hydrocarbons such as benzene, toluene, xylene, dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1 Chlorinated hydrocarbons such as 1,2-dichloropropane and trichloroethylene, nitrogen-containing compounds such as n-butylamine, isopropanolamine, diethylamine, triethanolamine, ethylenediamine and triethylenediamine, Lil, N- methylpyrrolidone, N, N- dimethylformamide, aprotic polar solvents such as dimethyl sulfoxide and the like. However, when the undercoat layer is provided on the electrophotographic photosensitive member, the solvent and the dispersion medium are preferably those that do not dissolve the undercoat layer. In addition, such a solvent and a dispersion medium may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

Furthermore, although the ratio of the charge generating material to the binder resin is arbitrary, it is usually 30 parts by weight or more, preferably 40 parts by weight or more, and usually 500 parts by weight or less, preferably 100 parts by weight with respect to 100 parts by weight of the binder resin. Or less.
Furthermore, although the film thickness of the charge generation layer is also arbitrary, it is usually 0.05 μm or more, preferably 0.1 μm or more, and usually 10 μm or less, preferably 5 μm or less.

  Furthermore, any method can be used for dispersing the charge generation material in the dispersion medium. For example, the charge generation material is dispersed and dissolved in an appropriate dispersion medium using a ball mill, an ultrasonic dispersion device, a paint shaker, an attritor, a sand grinder, or the like. After that, it is preferable to mix with various raw materials. During dispersion, it is effective to reduce the particle size of the charge generation material to a particle size of usually 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less.

  Further, the charge generation layer may contain other components. For example, well-known antioxidants, plasticizers, ultraviolet absorbers, electron-withdrawing compounds, leveling agents for the purpose of improving film-forming properties, flexibility, coating properties, stain resistance, gas resistance, light resistance, etc. Further, additives such as a visible light shielding agent may be contained.

[Ii. Charge transport layer]
On the other hand, the charge transport layer contains a charge transport material and usually contains a binder resin and other components used as necessary. The photoreceptor of the present invention uses the first and second charge transport materials described above as the charge transport material used here. The photoreceptor of the present invention may be used in combination with other charge transport materials in addition to the first and second charge transport materials.

  Specifically, the charge transport layer is prepared by, for example, preparing a coating solution by dissolving or dispersing a charge transport material and a binder resin in a solvent or a dispersion medium. In addition, in the case of a reverse lamination type photosensitive layer, it can be obtained by coating and drying on a conductive support (on the undercoat layer when an undercoat layer is provided). Moreover, the solvent or dispersion medium used in this case is arbitrary.

  In the charge transport layer, the binder resin is used for securing the film strength of the charge transport layer. There is no limitation on the type, and a known resin can be used arbitrarily. For example, butadiene resin, styrene resin, vinyl acetate resin, vinyl chloride resin, acrylic ester resin, methacrylic ester resin, vinyl alcohol resin, ethyl alcohol Polymers and copolymers of vinyl compounds such as vinyl ether, polyvinyl butyral resin, polyvinyl formal resin, partially modified polyvinyl acetal, polycarbonate resin, polyester resin, polyarylate resin, polyamide resin, polyurethane resin, cellulose ester resin, phenoxy resin, silicon Examples thereof include resins, silicon-alkyd resins, poly-N-vinylcarbazole resins and the like. Of these, polycarbonate resins and polyarylate resins are particularly preferable. These can also be used by crosslinking with an appropriate curing agent by heat, light or the like. Moreover, 1 type of binder resin may be used independently, and 2 or more types may be used together by arbitrary combinations and a ratio.

As the charge transport material, at least one of the first and second charge transport materials described above is used. Further, other charge transport materials used in combination therewith are not particularly limited, and known charge transport materials can be arbitrarily used.
Examples of other 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 , Indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, thiadiazole derivatives, heterocyclic compounds such as benzofuran derivatives, aniline derivatives, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives and multiple types of these compounds 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.
In addition, another charge transport substance may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios. However, it is preferable that the ratio of the first and second charge transport materials in the charge transport material to be used is larger.

  The ratio of the binder resin and the charge transport material is arbitrary, but the charge transport material is usually used at a ratio of 20 parts by weight or more with respect to 100 parts by weight of the binder resin. Among these, 30 parts by weight or more is preferable from the viewpoint of residual potential reduction, and 40 parts by weight or more is more preferable from the viewpoint of stability and charge mobility when repeatedly used. On the other hand, from the viewpoint of thermal stability of the photosensitive layer, the charge transport material is usually used at a ratio of 150 parts by weight or less. Among these, 120 parts by weight or less is preferable from the viewpoint of compatibility between the charge transport material and the binder resin, 100 parts by weight or less is more preferable from the viewpoint of printing durability, and 80 parts by weight or less is particularly preferable from the viewpoint of scratch resistance.

In the multilayer photoreceptor, the thickness of the charge transport layer is not particularly limited and is arbitrary, but from the viewpoint of long life, image stability, and further from the viewpoint of high resolution, it is usually 5 μm or more, preferably 10 μm or more. Further, it is usually 50 μm or less, preferably 45 μm or less, and more preferably 30 μm or less.
Further, the charge transport layer may contain other components. Examples of other components include the same components as those exemplified in the charge generation layer.

[2-3-2. Single-layer type photosensitive layer]
The single-layer type photosensitive layer has a structure in which a charge generating substance is further dispersed in the charge transport medium having the above-described mixing ratio. That is, the single-layer type photosensitive layer is formed using a binder resin in order to ensure film strength, in the same manner as the charge transport layer of the multilayer photoreceptor, in addition to the charge generation material and the charge transport material. Specifically, a charge generation material, a charge transport material, and various binder resins are dissolved or dispersed in a solvent or dispersion medium to prepare a coating liquid, and the coating liquid is formed on a conductive support (when an undercoat layer is provided). It can be obtained by coating and drying on the undercoat layer. However, the single-layer type photosensitive layer used in the photoreceptor of the present invention contains at least one of the first and second charge transport materials.

  The types of the charge transport material and the binder resin and the use ratios thereof are the same as those described for the charge transport layer of the multilayer photoreceptor. Therefore, in the single-layer type photosensitive layer, at least one of the first and second charge transport materials is contained, and these can be used in combination with any known charge transport material. Usually, a charge generation material is further dispersed in a charge transport medium comprising a charge transport material and a binder resin.

The charge generation material is the same as that described for the charge generation layer of the multilayer photoreceptor.
However, in the case of a photosensitive layer of a single layer type photoreceptor, the particle size of the charge generating substance is arbitrary, but it is usually desirable to make it sufficiently small. Specifically, the range is usually 1 μm or less, preferably 0.5 μm or less.

The amount of the charge generating material dispersed in the single-layer type photosensitive layer is arbitrary. However, if the amount is too small, sufficient sensitivity cannot be obtained, but if it is too large, there are problems such as a decrease in chargeability and a decrease in sensitivity. Therefore, it is desirable to use in the range of usually 0.1% by weight or more, preferably 1% by weight or more, and usually 50% by weight or less, preferably 20% by weight or less based on the whole single-layer type photosensitive layer.
The film thickness of the single-layer type photosensitive layer is arbitrary, but is usually in the range of 5 μm or more, preferably 10 μm or more, and usually 100 μm or less, preferably 50 μm or less.

Further, the use ratio of the binder resin and the charge generation material in the single-layer type photosensitive layer is not limited and is arbitrary, but the charge generation material is usually 0.1 parts by weight or more, preferably 1 with respect to 100 parts by weight of the binder resin. It is desirable that the amount is not less than part by weight, and usually not more than 30 parts by weight, preferably not more than 10 parts by weight.
Further, as in the case of the laminated photosensitive layer, the photosensitive layer may contain other components.

[2-4. Other layers]
In both the multilayer type photoreceptor and the single layer type photoreceptor, other layers of the undercoat layer and the photosensitive layer (that is, the charge generation layer and the charge transport layer) may be provided.
For example, a protective layer may be provided for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to discharge products generated from a charger or the like.

The protective layer is formed by containing a conductive material in a suitable binder resin, or charge transporting ability such as a triphenylamine skeleton as described in JP-A-9-190004 and JP-A-10-252377. It can form using the copolymer using the compound which has this.
There is no restriction | limiting in the electroconductive material used for a protective layer. For example, aromatic amino compounds such as TPD (N, N′-diphenyl-N, N′-bis- (m-tolyl) benzidine), antimony oxide, indium oxide, tin oxide, titanium oxide, tin oxide-antimony oxide, Metal oxides such as aluminum oxide and zinc oxide can be used, but are not limited thereto.

  Moreover, there is no restriction | limiting also about binder resin used for a protective layer, Although arbitrary resin can be used, For example, a polyamide resin, a polyurethane resin, a polyester resin, an epoxy resin, a polyketone resin, a polycarbonate resin, a polyvinyl ketone resin, a polystyrene resin In addition, known resins such as polyacrylamide resin and siloxane resin can be used, and charge transporting ability such as triphenylamine skeleton as described in JP-A-9-190004 and JP-A-10-252377 can be used. A copolymer of the skeleton having the above resin can also be used.

Furthermore, the protective layer is preferably configured so that the electric resistance is usually 10 ⁹ Ω · cm or more and 10 ¹⁴ Ω · cm or less. If the electric resistance is higher than the above range, the residual potential may increase and an image with much fog may be formed. On the other hand, if it is lower than the above range, there is a risk that the image is blurred and the resolution is lowered. Further, it is desirable that the protective layer is configured so as not to substantially prevent transmission of light irradiated for image exposure.

  In addition, for the purpose of reducing frictional resistance and wear on the surface of the photoconductor, and increasing the transfer efficiency of toner from the photoconductor to the transfer belt and paper, the surface layer is made of fluorine resin, silicon resin, polyethylene resin, or the like. The protective layer may contain particles made of the above resin or inorganic compound particles. Alternatively, a layer containing these resins and particles may be newly formed as a surface layer.

[2-5. Formation method of each layer]
The formation method of each layer (including the photosensitive layer and the undercoat layer) constituting the above-described photoreceptor is arbitrary, but usually a coating solution obtained by dissolving or dispersing a substance to be contained in a solvent or a dispersion medium. Are formed by repeating the coating / drying step sequentially for each layer using a known coating method.
The type and amount of the solvent or dispersion medium used in this case are not particularly limited, but considering the purpose of each layer and the properties of the selected solvent / dispersion medium, the physical properties such as the solid content concentration and viscosity of the coating liquid are in a desired range. It is preferable to adjust as appropriate.

Examples of usable solvents or dispersion media include saturated aliphatic solvents such as pentane, hexane, octane and nonane, aromatic solvents such as toluene, xylene and anisole, and halogenated solvents such as chlorobenzene, dichlorobenzene and chloronaphthalene. Aromatic solvents, amide solvents such as dimethylformamide and N-methyl-2-pyrrolidone, alcohol solvents such as methanol, ethanol, isopropanol, n-butanol and benzyl alcohol, aliphatic polyhydric alcohols such as glycerin and polyethylene glycol , Chain solvents such as acetone, cyclohexanone, methyl ethyl ketone, and cyclic ketone solvents, ester solvents such as methyl formate, ethyl acetate, n-butyl acetate, halogenated hydrocarbons such as methylene chloride, chloroform, 1,2-dichloroethane Solvent Aprotic polar solvents such as chain ethers such as tilether, dimethoxyethane, tetrahydrofuran, 1,4-dioxane, methylcellosolve, ethylcellosolve, and cyclic ether solvents, acetonitrile, dimethyl sulfoxide, sulfolane, hexamethylphosphate triamide, etc. , N-butylamine, isopropanolamine, diethylamine, triethanolamine, nitrogen-containing compounds such as ethylenediamine, triethylenediamine and triethylamine, mineral oil such as ligroin, and water.
In addition, a solvent and a dispersion medium may each be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

Furthermore, the concentration and viscosity of the coating solution used for forming each layer are arbitrary, and may be determined to an appropriate value according to the layer to be formed.
For example, in the case of a single layer type photoreceptor and a charge transport layer of a laminated type photoreceptor, the solid content concentration of the coating solution is usually 5% by weight or more, preferably 10% by weight or more, and usually 40% by weight or less, Preferably it is 35 weight% or less of range. Further, the viscosity of the coating solution is usually in the range of 10 cps or more, preferably 50 cps or more, and usually 500 cps or less, preferably 400 cps or less.

  In the case of a charge generating layer of a multilayer photoreceptor, the solid content concentration of the coating solution is usually 0.1% by weight or more, preferably 1% by weight or more, and usually 15% by weight or less, preferably 10% by weight. % Or less. The viscosity of the coating solution is usually 0.01 cps or more, preferably 0.1 cps or more, and usually 20 cps or less, preferably 10 cps or less.

  Further, the ratio of the solvent in the coating solution for forming the charge generation layer of the multilayer photoreceptor is arbitrary, but is usually 0.2% by weight or more, preferably from the viewpoint of the effect of reducing the potential remaining on the photoreceptor surface. Is preferably 0.5% by weight or more, more preferably 2% by weight or more. Further, from the viewpoint of not extremely reducing the drying rate after coating, it is usually 40% by weight or less, preferably 20% by weight or less, more preferably 10% by weight or less.

  Moreover, there is no restriction | limiting in the coating method of a coating liquid, A well-known coating method can be used arbitrarily. Specific examples include dip coating, spray coating, spinner coating, bead coating, wire bar coating, blade coating, roller coating, air knife coating, curtain coating, etc. A known coating method can also be used. In addition, application | coating may be made to perform said application | coating method independently, and may be made to combine two or more types of application | coating methods.

  Furthermore, the drying method of the coating solution is also arbitrary. For example, after touch-drying at room temperature, it is usually dried in a temperature range of 30 ° C. or higher and usually 200 ° C. or lower for 1 minute to 2 hours with no wind or air blowing. Can be dried. The heating temperature may be constant or the heating may be performed while changing the temperature during drying.

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

  As shown in FIG. 1, the image forming apparatus includes an electrophotographic photosensitive member 1, a charging device (charging unit) 2, an exposure device (exposure unit) 3, and a developing device (developing unit) 4. Accordingly, a transfer device 5, a cleaning device 6, and a fixing device 7 are provided.

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

  The charging device 2 charges the electrophotographic photosensitive member 1 and uniformly charges the surface of the electrophotographic photosensitive member 1 to a predetermined potential. In FIG. 1, a roller-type charging device (charging roller) is shown as an example of the charging device 2, but other corona charging devices such as 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 cartridges having both of them (the electrophotographic photosensitive member cartridge of the present invention; hereinafter referred to as “photosensitive cartridge” as appropriate), and the main body of the image forming apparatus. Designed to be removable from. For example, when the electrophotographic photoreceptor 1 or the charging device 2 deteriorates, the photoreceptor cartridge can be removed from the image forming apparatus main body, and another new photosensitive cartridge can be mounted on the image forming apparatus main body. ing. Also, toner (developer), which will be described later, is often stored in a toner cartridge and designed to be removable from the main body of the image forming apparatus, and when the toner in the toner cartridge used is exhausted, The toner cartridge is removed from the main body of the image forming apparatus, and another new toner cartridge can be mounted. Further, a cartridge equipped with all of the electrophotographic photosensitive member 1, the charging device 2, and the toner may be used.

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

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

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

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

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

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

  The type of the toner T is arbitrary, and besides the pulverized toner, a polymerized toner using a suspension polymerization method, an emulsion polymerization method, or the like can be used. In particular, when a polymerized toner is used, a toner having a small particle diameter of about 4 μm to 8 μm is preferable, and the toner particles can be used in a variety of shapes from a nearly spherical shape to a shape outside 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 the toner image formed on the electrophotographic photosensitive member 1 to a recording paper (paper, medium) P. Is.

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

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

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

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

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

  The developing device 4 thins the toner T supplied by the supply roller 43 with a regulating member (developing blade) 45 and has a predetermined polarity (here, the same polarity as the charging potential of the electrophotographic photosensitive member 1). Negatively charged) and conveyed while being carried on the developing roller 44 and brought into contact with the surface of the electrophotographic photosensitive member 1.

When the charged toner T carried on the developing roller 44 contacts the surface of the electrophotographic photoreceptor 1, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the electrophotographic photoreceptor 1. This toner image is transferred onto the recording paper P by the transfer device 5. Thereafter, the toner remaining on the photosensitive surface of the electrophotographic photosensitive member 1 without being transferred is removed by the cleaning device 6.
After the transfer of the toner image onto the recording paper P, the final image is obtained by passing the fixing device 7 and thermally fixing the toner image onto the recording paper P.

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

The image forming apparatus may be further modified. For example, the image forming apparatus may be configured to perform a pre-exposure process, an auxiliary charging process, or the like, or may be configured to perform offset printing. A full-color tandem system configuration using toner may be used.
However, an image forming apparatus using reversal development is particularly effective in the characteristics of the photoreceptor of the present invention.

  In this embodiment, the electrophotographic photosensitive member cartridge of the present invention has been described by exemplifying the photosensitive member cartridge including the electrophotographic photosensitive member 1 and the charging device 2. However, the electrophotographic photosensitive member cartridge of the present invention is electrophotographic. If the photosensitive member 1 includes at least one of a charging device (charging unit) 2, an exposure device (exposure unit) 3, a developing device (developing unit) 4, and a cleaning device (cleaning unit) 6. Good. Specifically, for example, the electrophotographic photosensitive member cartridge of the present invention includes an electrophotographic photosensitive member 1, a charging device (charging unit) 2, an exposure device (exposure unit) 3, a developing device (developing unit) 4, and a cleaning device ( You may comprise as a cartridge provided with all the cleaning parts 6).

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the following examples are shown to explain the present invention in detail, and the present invention can be arbitrarily modified without departing from the gist thereof. Can be implemented. The photoreceptors produced in Examples 1 to 13 and Comparative Examples 1 to 14 are referred to as photoreceptors A-1 to A-13 and photoreceptors P-1 to P-14, respectively.

[Examples 1-8, Comparative Examples 1-9]
<Production of electrophotographic photoreceptor>
Using a conductive support in which an aluminum vapor-deposited layer (thickness 70 nm) is formed on the surface of a biaxially stretched polyethylene terephthalate resin film (thickness 75 μm), the following undercoat layer dispersion is formed on the aluminum vapor-deposited layer of the conductive support The liquid was applied by a bar coater so that the film thickness after drying was 1.25 μm and dried to form an undercoat layer.

  The undercoat layer dispersion was produced as follows. That is, a slurry obtained by mixing 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 with respect to the titanium oxide in a ball mill. After drying, the hydrophobic treated titanium oxide obtained by further washing with methanol and drying was dispersed by a ball mill in a mixed solvent of methanol / 1-propanol to obtain a hydrophobized titanium oxide dispersed slurry. The dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam [following formula (A)] / bis (4-amino-3-methylcyclohexyl) methane [following formula (B)] / hexa The composition molar ratio of methylenediamine [following formula (C)] / decamethylene dicarboxylic acid [following formula (D)] / octadecamethylene dicarboxylic acid [following formula (E)] is 75% / 9.5% / 3%. /9.5%/3% copolymerized polyamide pellets with heating and stirring and mixing to dissolve the polyamide pellets, followed by ultrasonic dispersion treatment to give methanol / 1-propanol / toluene. A dispersion for an undercoat layer having a solid content concentration of 18.0% by weight and containing a hydrophobically treated titanium oxide / copolymerized polyamide in a weight ratio of 3/1 at a weight ratio of 7/1/2. .

  Separately, 10 parts by weight of D-type oxytitanium phthalocyanine {showing a diffraction peak at 27.3 ° at a Bragg angle (2θ ± 0.2 °) in an X-ray diffraction spectrum for CuKa characteristic X-ray} -Methylpentanone-2 In addition to 150 parts by weight, the mixture was pulverized and dispersed in a sand grind mill for 1 hour. Thereafter, 100 parts by weight of a 5 wt% 1,2-dimethoxyethane solution of polyvinyl butyral (“Denkabutyral # 6000C” manufactured by Denki Kagaku Kogyo Co., Ltd.) as a binder resin, and phenoxy resin (“PKHH” manufactured by Union Carbide) A coating solution for a charge generation layer was prepared by adding 100 parts by weight of a 5 wt% 1,2-dimethoxyethane solution. The charge generation layer coating solution was applied onto the undercoat layer of the conductive support with a bar coater so that the film thickness after drying was 0.4 μm, and dried to form a charge generation layer. .

  Separately, charge transport materials shown in Table 2-1 and Table 2-2 below (that is, hydrazone compounds and benzidine derivatives shown in Table 2-1 in Examples 1 to 8, Table 2 in Comparative Examples 1 to 9) -2 hydrazone compound and / or benzidine derivative) shown in Tables 2-1 and 2-2 below, 100 parts by weight of binder resin, and 0.03 part by weight of silicone oil as a leveling agent, A charge transport layer coating solution was prepared by dissolving in 640 parts by weight of a tetrahydrofuran / toluene (weight ratio 8/2) mixed solvent. Here, as the binder resin, 51 mol% of a repeating unit having 2,2-bis (4-hydroxy-3-methylphenyl) propane as an aromatic diol component shown below and 1,1-bis (4-hydroxy) are used. A polycarbonate resin (viscosity average molecular weight 30000) having a terminal structure derived from p-tert-butylphenol, comprising 49 mol% of repeating units having phenyl) -1-phenylethane as an aromatic diol component.

  The prepared charge transport layer coating solution is applied onto the charge generation layer with a film applicator so that the film thickness after drying is 25 μm, and dried to form a charge transport layer. Electrophotographic photoreceptors A-1 to A-8 and P-1 to P-9 having the same were produced.

<Evaluation of electrical characteristics of electrophotographic photoreceptor>
The electrophotographic characteristics of the obtained electrophotographic photoreceptors A-1 to A-8, P-1 to P-9 were measured by the following methods.
Photoreceptors A-1 to A-8 are prepared in an electrophotographic characteristic evaluation apparatus produced in accordance with the standard of the Electrophotographic Society (“Continued Electrophotographic Technology Fundamentals and Applications” edited by the Electrophotographic Society, published by Corona, pages 404-405). , P-1 to P-9 were mounted, and electrical characteristics were evaluated by a cycle of charging, exposure, potential measurement, and static elimination. At this time, the charged photosensitive member is charged so that the initial surface potential becomes −700 V, and the light of the halogen lamp is irradiated with monochromatic light of 780 nm by the interference filter, and irradiation is performed when the surface potential becomes −350 V. Energy (μJ / cm ² ) was measured as sensitivity. Further, the 660 nm LED light was used as the static elimination light, and the residual potential Vr (−V) after the irradiation was measured.

The evaluation results for each of the photoreceptors A-1 to A-8 are shown in Table 2-1, and the evaluation results for each of the photoreceptors P-1 to P-9 are shown in Table 2-2.
However, in the photoconductors P-4 and P-5 produced in Comparative Examples 4 and 5, since the crystal was generated on the surface of the photoconductor after the application of the coating solution for the charge transport layer, the residual potential Vr and the irradiation energy can be measured. There wasn't.

  As can be seen from Tables 2-1 and 2-2, the photoreceptors A-1 to A-8 have a smaller residual potential Vr than the photoreceptors P-1 to P-9, and the surface potential is set to -350V. The value of the irradiation energy required for this is also small. Therefore, it was confirmed that the photoreceptors A-1 to A-8 as examples of the present invention had a smaller residual potential and higher sensitivity than the photoreceptors P-1 to P-9 as comparative examples. .

[Examples 9 to 13, Comparative Examples 10 to 14]
No subbing layer was formed, and instead of D-type oxytitanium phthalocyanine, A-type oxytitanium phthalocyanine {CuKa characteristic X-ray diffraction spectrum for X-ray diffraction with a Bragg angle (2θ ± 0.2 °) of 9.3 °, Further, the charge transport materials and the amounts used thereof are as shown in Tables 3-1 and 3-2 below (that is, Examples 9 to 13). In Table 3, the hydrazone compound and / or the benzidine derivative shown in Table 3-1 were used only in parts by weight shown in Table 3-1, and in Comparative Examples 10 to 14, the hydrazone compound and / or the benzidine derivative shown in Table 3-2 were used. 2), and the electrophotographic photoreceptors A-9 to A-13, P-10 to P- are the same as in Example 1 except that the thickness of the charge transport layer is 20 μm. 14 It was manufactured.

The electrophotographic characteristics of each of the obtained electrophotographic photoreceptors A-9 to A-13 and P-10 to P-14 are each measured in a static manner using a photoreceptor evaluation apparatus (Cynthia 55, manufactured by Gentec Corporation). Measurement was performed as follows.
First, the electrophotographic photosensitive member is discharged with a scorotron charger in a dark place so that the surface potential is about −700 V, and the electrophotographic photosensitive member is charged at a constant speed (125 mm / sec) and charged. The voltage was measured to determine the initial voltage V0.

Thereafter, the potential drop DD when allowed to stand for 2.5 seconds was measured. Next, irradiation with 780 nm monochromatic light having an intensity of 1.0 (μW / cm ² ) was performed, and the half-exposure energy E _1/2 (μJ / cm ²⁾ required until the photoreceptor surface potential changed from −550 V to −275 V. ) And the residual potential Vr (−V) 10 seconds after irradiation.
The evaluation results for each of the photoreceptors A-9 to A-13 are shown in Table 3-1, and the evaluation results for each of the photoreceptors P-10 to P-14 are shown in Table 3-2.
However, in the photoconductors P-12 and P-13 produced in Comparative Examples 12 and 13, since crystals were generated on the surface of the photoconductor after application of the coating solution for the charge transport layer, the residual potential Vr and the half exposure energy were measured. I could not do it.

As can be seen from Tables 3-1 and 3-2, when the photoreceptors A-9 to A-11, which are photoreceptors using the same kind of hydrazone compound, are compared with the photoreceptor P-10, the photoreceptor A-9. -A-11 has lower residual potential Vr and half-exposure energy than the photoreceptor P-10. Further, even when the photoconductors A-12 and A-13, which are photoconductors using the same kind of hydrazone compound, are compared with the photoconductor P-11, the photoconductors A-12 and A-13 are the photoconductor P-. The residual potential Vr and the half exposure energy are smaller than 11. Further, in the photoreceptors A-12 and P-13 using only the benzidine derivative, crystals were deposited on the photoreceptor surface and image formation could not be performed. Further, even when a hydrazone compound and a benzidine derivative are used in combination, in the photoreceptor P-14 that uses a combination other than those specified in the present invention, the photoreceptor A-12, which is a photoreceptor using the same kind of hydrazone compound. The residual potential Vr and half-exposure energy are larger than those of A-13.
From the above, it was confirmed that the photoreceptor of the present invention has high sensitivity and can reduce the residual potential.

[Example 14]
<Image formation test and photoreceptor stability / durability test>
On the aluminum tube having a diameter of 3 cm and a length of 25.4 cm, the surface of which was anodized and sealed, a charge generation layer and charge transport layer coating solution prepared in the same manner as the electrophotographic photoreceptor A-2 was prepared. The electrophotographic photosensitive drum having a charge generation layer of 0.3 μm and a charge transport layer of 20 μm was prepared by sequentially applying and drying by a dip coating method.

When this electrophotographic photosensitive drum was mounted on a laser printer manufactured by Hewlett-Packard Co., Ltd. and a laser jet 4 (LJ4) modified machine, an image test was performed, and a good image free from image defects and noise was obtained.
Subsequently, 10,000 sheets were continuously printed, but the image was not deteriorated such as ghost, fog and black spots, and was stable.

[Comparative Example 15]
An electrophotographic photosensitive member was prepared in the same manner as in Example 14 except that the material used in the electrophotographic photosensitive member P-2 was used instead of the electrophotographic photosensitive member A-2. Stability and durability tests were conducted.
As a result, the image density was low from the beginning, and fogging was observed in the repetition.

  From Example 14 and Comparative Example 15, it is confirmed that if an image forming apparatus using a photoconductor as an example of the present invention is used, an image with higher image quality can be formed than an image forming apparatus using a conventional photoconductor. did it.

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

FIG. 1 illustrates an embodiment of the present invention, and is a schematic diagram illustrating a main configuration of an image forming apparatus using the electrophotographic photosensitive member of the present invention.

Explanation of symbols

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

Claims (5)

An electrophotographic photoreceptor comprising a photosensitive layer containing a hydrazone compound of the following formula (1) and a benzidine derivative of the following formula (2).

{In Formula (1), R ¹ and R ² each independently represents an organic group. Ar ¹ and Ar ² each independently represents an aryl group. Ar ³ represents an arylene group. M and n represent integers satisfying 0 ≦ m ≦ 5, 0 ≦ n ≦ 5, and 1 ≦ m + n, respectively. }

{In Formula (2), Ar ^{4 to} Ar ⁷ each independently represents an aryl group. } An electrophotographic photoreceptor comprising a photosensitive layer containing a hydrazone compound of the following formula (3) and a tetraphenylbenzidine derivative having 4 or more substituents.

{In Formula (3), Ar < ⁸ > -Ar < ¹¹ > represents an aryl group each independently. Ar ¹² represents an arylene group. } The electron according to claim 1 or 2, characterized in that it contains oxytitanium phthalocyanine having a diffraction peak at 27.3 ° in a Bragg angle (2θ ± 0.2 °) in CuKα characteristic X-ray diffraction. Photoconductor. The electrophotographic photosensitive member according to any one of claims 1 to 3,
A charging unit for charging the electrophotographic photosensitive member, an exposure unit for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image, and a developing unit for developing the electrostatic latent image formed on the electrophotographic photosensitive member An electrophotographic photosensitive member cartridge comprising: at least one of a cleaning unit that removes the developer from the electrophotographic photosensitive member. The electrophotographic photosensitive member according to any one of claims 1 to 3,
A charging unit for charging the electrophotographic photosensitive member;
Exposing the charged electrophotographic photoreceptor to form an electrostatic latent image; and
An image forming apparatus comprising: a developing unit that develops an electrostatic latent image formed on the electrophotographic photosensitive member.

Images