JP2007334099A - Electrophotographic photoreceptor and method for manufacturing electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having high sensitivity upon exposure by uniformly dispersing a charge generating agent having excellent charge generating ability in a photosensitive layer, and to provide a method for easily manufacturing the electrophotographic photoreceptor. <P>SOLUTION: The electrophotographic photoreceptor and the method for manufacturing the photoreceptor have a photosensitive layer of a single layer structure containing at least a charge generating agent, a hole transporting agent, an electron transporting agent and a binder resin on a substrate, wherein the photosensitive layer contains a particulate quinacridone pigment as well as an oxotitanyl phthalocyanine crystal as a charge generating agent, and the average particle diameter of the quinacridone pigment is controlled within a range of 30 to 150 nm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member and a method for producing the electrophotographic photosensitive member, and particularly relates to an electrophotographic photosensitive member having excellent sensitivity and a method for producing such an electrophotographic photosensitive member.

In general, organic photoconductors are often used as electrophotographic photoconductors used in electrophotographic machines such as copying machines and laser printers due to demands for low cost and low environmental pollution.
In addition, the surface of such an organic photoreceptor is charged (main charging step) and an electrostatic latent image is formed (exposure step), and then the electrostatic latent image is applied with a developing bias voltage. An image forming process is performed in which toner development (development process) is performed, and the formed toner image is transferred to transfer paper by a reversal development method (transfer process), which is heated and fixed to form a predetermined image. ing.
The residual toner on the organic photoconductor is removed using a cleaning blade (cleaning step), and the residual charge on the organic photoconductor is erased by an LED or the like (static elimination step). .
In order to increase the speed of such image formation, the organophotoreceptor is rotated and used at a high speed, so that the sensitivity to exposure needs to be higher than in the past.

  However, a metal-free phthalocyanine crystal generally used as a charge generating agent used in a single layer type electrophotographic photosensitive member has insufficient charge generating ability and cannot achieve high sensitivity. The problem was seen.

Therefore, in place of the metal-free phthalocyanine crystal, an oxotitanyl phthalocyanine crystal, particularly, a quantum yield of 90%, and a Y-type oxo titanyl phthalocyanine crystal having more excellent charge generation ability is used as a charge generator. Attempts have been made to achieve high sensitivity (for example, Patent Documents 1 and 2).
Patent No. 3463032 (Claims) JP 2004-145284 (Claims)

However, as in Patent Documents 1 and 2, simply using a Y-type oxotitanyl phthalocyanine crystal excellent in charge generation ability as a charge generation agent has been insufficient in increasing sensitivity. This is because the Y-type oxotitanyl phthalocyanine crystal is inferior in dispersibility in an organic solvent, so that it cannot be uniformly dispersed in the photosensitive layer and cannot fully exhibit its excellent charge generation ability. Because.
In addition, since the Y-type oxotitanyl phthalocyanine crystal is inferior in dispersibility in an organic solvent, the Y-type oxotitanyl phthalocyanine crystal aggregates and precipitates when the photosensitive layer coating solution is stored for a long period of time. Also, there has been a problem that it is difficult to efficiently manufacture the electrophotographic photosensitive member.

Accordingly, the inventors of the present invention, as a result of intensive studies, have included, in a single-layer electrophotographic photoreceptor, a particulate quinacridone pigment having a predetermined average particle diameter, and an oxotitanyl phthalocyanine crystal as a charge generator. It has been found that a high-sensitivity electrophotographic photosensitive member can be easily produced by using it.
That is, an object of the present invention is to provide an electrophotographic photoreceptor having high sensitivity to exposure and an easy method for producing such an electrophotographic photoreceptor.

  According to the present invention, there is provided an electrophotographic photosensitive member having a photosensitive layer having a single layer structure including at least a charge generating agent, a hole transporting agent, an electron transporting agent, and a binder resin on a substrate, wherein the photosensitive layer comprises An electrophotographic photoreceptor comprising a particulate quinacridone pigment, an oxo titanyl phthalocyanine crystal as a charge generator, and an average particle diameter of the quinacridone pigment of 30 to 150 nm. Can be provided to solve the above-mentioned problems.

That is, the sensitivity of the electrophotographic photosensitive member to exposure can be improved by using an oxotitanyl phthalocyanine crystal having a charge generation ability superior to that of a metal-free phthalocyanine crystal generally used as a charge generator.
Further, due to the effect of the particulate quinacridone pigment having a predetermined average particle diameter, oxotitanyl phthalocyanine crystals that are inferior in dispersibility to metal-free phthalocyanine crystals can be effectively dispersed in the photosensitive layer. Excellent charge generation ability can be fully exhibited. Therefore, an electrophotographic photosensitive member having high sensitivity to exposure can be obtained.

Further, in constituting the electrophotographic photoreceptor of the present invention, the amount of the quinacridone pigment added is set to a value within the range of 50 to 200 parts by weight with respect to 100 parts by weight of the oxotitanyl phthalocyanine crystal as the charge generating agent. Is preferred.
By configuring in this way, it is possible to adjust the balance between the interaction between the quinacridone pigment and the oxotitanyl phthalocyanine crystal in the coating solution for the photosensitive layer, and the compatibility with other components in the coating solution for the photosensitive layer, It becomes easier.

In constituting the electrophotographic photosensitive member of the present invention, the ratio of the absorbance (A2) of the quinacridone pigment to light having a wavelength of 780 nm and the absorbance of the oxotitanylphthalocyanine crystal to light having a wavelength of 780 nm (A1) is as follows. It is preferable to satisfy Formula (1).
1.0 <A1 / A2 <10.0 (1)
By comprising in this way, it can suppress that the light absorption of an oxo titanyl phthalocyanine crystal is inhibited with a quinacridone pigment, and can improve the charge generation efficiency of this oxo titanyl phthalocyanine crystal. Therefore, an electrophotographic photosensitive member having high sensitivity to exposure can be obtained.

In constituting the electrophotographic photosensitive member of the present invention, the quinacridone pigment is preferably insoluble in an organic solvent.
By comprising in this way, the particle size of the particle | grains which consist of a quinacridone pigment can be hold | maintained in the value within a preferable range in the coating liquid for photosensitive layers used when manufacturing a photosensitive layer. As a result, the balance between the interaction between the quinacridone pigment and the oxotitanyl phthalocyanine crystal and the compatibility with the other components in the coating solution for the photosensitive layer becomes suitable, and the dispersibility of the oxo titanyl phthalocyanine crystal as a charge generating agent. Can be improved.

Further, in constituting the electrophotographic photosensitive member of the present invention, it is preferable that an oxo titanyl phthalocyanine crystal having the following characteristics (a) and (b) or any one of the characteristics is contained as a charge generator.
(A) In the differential scanning calorimetry, there is no peak in the range of 50 to 400 ° C. other than the peak due to vaporization of the adsorbed water. (B) In the differential scanning calorimetry, except for the peak due to vaporization of the adsorbed water. , Having no peak in the range of 50 to 200 ° C., and having one peak in the range of 200 to 400 ° C. By configuring in this way, the aging stability and dispersibility of the oxotitanyl phthalocyanine crystal can be improved. Can be improved more.

In constituting the electrophotographic photosensitive member of the present invention, it is preferable to contain an oxotitanyl phthalocyanine crystal having the following characteristics (c) as a charge generator.
(C) After immersing in an organic solvent for 24 hours, the CuKα characteristic X-ray diffraction spectrum has a maximum peak at least at Bragg angle 2θ ± 0.2 ° = 27.2 ° and a peak at 26.2 °. Preferably not.
By comprising in this way, the aging stability and dispersibility of this oxo titanyl phthalocyanine crystal can further be improved.

Another embodiment of the present invention is a method for producing an electrophotographic photoreceptor comprising a single layer type photosensitive layer containing at least a charge generator, a hole transport agent, an electron transport agent, and a binder resin on a substrate. In a binder resin solution containing a binder resin and an organic solvent, an oxotitanyl phthalocyanine crystal as a charge generator, a hole transport agent, an electron transport agent, and an average particle size within a range of 30 to 150 nm. A step of producing a photosensitive layer coating solution for forming a photosensitive layer by dispersing a particulate quinacridone pigment having a value, and coating the photosensitive layer coating solution on a substrate, followed by drying to form a photosensitive layer A process for forming an electrophotographic photosensitive member.
That is, even when the photosensitive layer coating solution is stored for a long period of time, it suppresses aggregation and precipitation of oxotitanyl phthalocyanine crystals as charge generating agents in the photosensitive layer coating solution, thereby improving the dispersibility. Can be effectively maintained.
Therefore, an electrophotographic photoreceptor having high sensitivity to exposure can be easily produced.

[First Embodiment]
The first embodiment of the present invention is an electrophotographic photosensitive member provided with a photosensitive layer having a single layer structure including at least a charge generating agent, a hole transporting agent, an electron transporting agent, and a binder resin on a substrate, The photosensitive layer contains a particulate quinacridone pigment, an oxo titanyl phthalocyanine crystal as a charge generator, and an average particle size of the quinacridone pigment of 30 to 150 nm. It is a photoreceptor.
Hereinafter, the electrophotographic photosensitive member of the first embodiment will be described separately for each component.

1. Basic Configuration As shown in FIG. 1A, a single-layer electrophotographic photosensitive member 10 is obtained by providing a single photosensitive layer 14 on a substrate (conductive substrate) 12. The photosensitive layer 14 contains a particulate quinacridone pigment having a predetermined average particle diameter, an oxotitanyl phthalocyanine crystal as a charge generator, a hole transport agent, an electron transport agent, and a binder resin in the same layer. It is characterized by.
The reason for this is that, as will be described later, the dispersion of the oxotitanyl phthalocyanine crystal by containing a quinacridone pigment having a predetermined average particle diameter and an oxo titanyl phthalocyanine crystal as a charge generator in the same photosensitive layer. This is because the photosensitivity can be improved and the sensitivity of the electrophotographic photosensitive member can be improved. In addition, by including both a hole transport agent and an electron transport agent in the same photosensitive layer, it is possible to efficiently transport charges generated from the oxotitanyl phthalocyanine crystal as a charge generating agent at the time of exposure. This is because it can.
In addition, as shown in FIG. 1B, an electrophotographic photosensitive member 10 ′ in which a barrier layer 16 is formed between the substrate 12 and the photosensitive layer 14 in a range that does not inhibit the characteristics of the electrophotographic photosensitive member may be used. . In addition, as shown in FIG. 1C, an electrophotographic photoreceptor 10 ″ having a protective layer 18 formed on the surface of the photosensitive layer 14 may be used.

2. Charge Generating Agent (1) Type As the charge generating agent used in the electrophotographic photosensitive member according to the present invention, a crystal of an oxotitanyl phthalocyanine compound represented by the following general formula (1) is used.
This is because the metal-free phthalocyanine crystal generally used as a charge generator cannot sufficiently achieve high sensitivity in an electrophotographic photoreceptor, whereas the oxo represented by the general formula (1). This is because if the crystal is a titanyl phthalocyanine compound, the quantum yield can be remarkably improved depending on the crystal type.
In addition, the compound represented by following formula (2) can be mentioned as a specific example of the oxo titanyl phthalocyanine compound represented by General formula (1).

(In the general formula (1), X ¹ , X ² , X ³ and X ⁴ are the same or different substituents, and each represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a cyano group, or a nitro group. And the repeating numbers a, b, c and d each represent an integer of 1 to 4, and may be the same or different.

Moreover, it is preferable that the crystal type in the oxo titanyl phthalocyanine crystal is a Y type.
This is because such a Y-type oxo titanyl phthalocyanine crystal improves the quantum yield in the charge generating agent, and can improve the sensitivity during exposure. That is, if the quantum yield is said to be about 90%, it is possible to efficiently generate charges according to the light irradiated by exposure, thereby sufficiently improving the sensitivity during exposure. This is because it can.

(2) Optical characteristics and thermal characteristics In addition, it is preferable to contain an oxotitanyl phthalocyanine crystal having the following characteristics (a) and (b) or one of the characteristics as a charge generator.
(A) In the differential scanning calorimetry, there is no peak in the range of 50 to 400 ° C. other than the peak due to vaporization of the adsorbed water. (B) In the differential scanning calorimetry, except for the peak due to vaporization of the adsorbed water. , Having no peak in the range of 50 to 200 ° C., and having one peak in the range of 200 to 400 ° C. This is because the aging stability of the oxotitanyl phthalocyanine crystal by this configuration This is because the dispersibility can be further improved.

More specifically, when the oxo titanyl phthalocyanine crystal has the characteristic (a), the oxo titanyl phthalocyanine crystal is a stable crystal that hardly undergoes crystal transition.
That is, even when a photosensitive layer coating solution is manufactured and used after being stored for a certain period of time, oxotitanyl phthalocyanine crystals are produced by the action of an organic solvent such as tetrahydrofuran contained in the photosensitive layer coating solution. Little crystal transition from type to α or β type occurs. Therefore, the oxo titanyl phthalocyanine crystal can maintain the Y type which is a crystal type excellent in charge generation.

Further, when the oxo titanyl phthalocyanine crystal has the characteristic (b), the aging stability and dispersibility of the oxo titanyl phthalocyanine crystal can be further improved.
More specifically, in the case of having the characteristics (b), the oxotitanyl phthalocyanine crystal can suppress crystal transition in an organic solvent and exhibits particularly excellent dispersibility in a coating solution for a photosensitive layer. can do.
That is, when producing a photosensitive layer coating solution for producing a photosensitive layer, the crystal type does not transition to α or β type, and the Y type can be maintained, and the dispersibility in the photosensitive layer coating solution is particularly high. Since it is excellent, charge generation at the time of exposure in the formed photosensitive layer can be performed very efficiently. Furthermore, the excellent dispersibility enables efficient charge transport between the oxotitanyl phthalocyanine crystal and the charge transport agent, thereby improving the sensitivity of the electrophotographic photoreceptor and increasing the sensitivity in the photosensitive layer. Generation of residual potential can be prevented and exposure memory can be effectively suppressed.
In addition, it is more preferable that one peak appearing in the range of 200 to 400 ° C. other than the peak accompanying vaporization of the adsorbed water appears in the range of 270 to 400 ° C., and the range of 300 to 400 ° C. More preferably, it appears within.

In addition, the oxo titanyl phthalocyanine crystal | crystallization which has the characteristic of (a) and (b) may be used individually, respectively, and may be used in combination.
Therefore, when the oxo titanyl phthalocyanine crystal having the characteristics of (a) and (b) is used in combination, the oxo titanyl phthalocyanine crystal having the characteristics of (a) by weight ratio: the oxo titanyl having the characteristics of (b) The phthalocyanine crystal is preferably in the range of 10/90 to 90/10, and more preferably in the range of 20/80 to 80/20.

Moreover, it is preferable to further contain another oxo titanyl phthalocyanine crystal other than the oxo titanyl phthalocyanine crystal having the characteristics (a) or (b) as the charge generating agent.
The reason for this is that the oxotitanyl phthalocyanine crystal having no characteristics of (a) or (b) may have poor stability over time and dispersibility in the coating solution for the photosensitive layer by itself. This is because the problem is remarkably improved by combining with an oxo titanyl phthalocyanine crystal having the characteristic (b).
That is, as long as a predetermined amount of the oxotitanyl phthalocyanine crystal having the characteristics (a) or (b) is used, even the conventional oxotitanyl phthalocyanine crystal not having the characteristics (a) or (b) can be suitably combined. Can be used. Therefore, by using an oxotitanyl phthalocyanine crystal having a plurality of properties as a charge generating agent in this way, it is easy to adjust the charge generating ability for exposure, and an inexpensive electrophotographic photosensitive member is provided. Can do.

Moreover, it is preferable to contain the oxo titanyl phthalocyanine crystal | crystallization which has the characteristic of the following (c) as a charge generator.
(C) After immersing in an organic solvent for 24 hours, the CuKα characteristic X-ray diffraction spectrum has a maximum peak at least at a Bragg angle 2θ ± 0.2 ° = 27.2 ° and a peak at 26.2 °. This is because, when the oxotitanyl phthalocyanine crystal has the characteristic (c), the oxo titanyl phthalocyanine crystal can control the crystal transition in the organic solvent more reliably.
That is, even when the oxo titanyl phthalocyanine crystal was actually immersed in an organic solvent such as tetrahydrofuran for 24 hours, it was confirmed that the crystal form did not transition to the α or β form and retained the Y form. This is because the crystal transition in the organic solvent can be reliably controlled.

Moreover, the thermal characteristic in an oxo titanyl phthalocyanine crystal can be measured as follows as an example.
That is, it can be measured under the following conditions using a differential scanning calorimeter (TAS-200 type, DSC8230D manufactured by Rigaku Corporation).
Sample pan: Aluminum heating rate: 20 ° C / min

Moreover, the optical characteristic in an oxo titanyl phthalocyanine crystal can be measured as follows as an example.
Specifically, 0.3 g of Y-type oxotitanyl phthalocyanine was dispersed in 5 g of tetrahydrofuran and stored in a closed system for 24 hours under conditions of a temperature of 23 ± 1 ° C. and a relative humidity of 50-60% RH. A sample holder of RINT1100 (manufactured by Rigaku Denki Co., Ltd.) is filled and measurement can be performed under the following conditions.
X-ray tube: Cu
Tube voltage: 40 kV
Tube current: 30 mA
Start angle: 3.0 °
Stop angle: 40.0 °
Scanning speed: 10 ° / min

(3) Addition amount The addition amount of the oxotitanyl phthalocyanine crystal as the charge generating agent is preferably set to a value in the range of 0.6 to 3.0% by weight with respect to the total amount of the photosensitive layer. .
The reason for this is that by making the addition amount of oxotitanyl phthalocyanine crystal within such a range, the dispersibility in the photosensitive layer becomes good, and when the electrophotographic photoreceptor is exposed, the oxo titanyl phthalocyanine is This is because the crystals can efficiently generate charges and also efficiently transport charges between the crystals and the charge transport agent.
That is, when the amount of oxotitanyl phthalocyanine added is less than 0.6% by weight, the amount of charge generation becomes insufficient, and it becomes difficult to form a predetermined electrostatic latent image on the electrophotographic photosensitive member. This is because there are cases. On the other hand, when the added amount of the charge generating agent exceeds 3% by weight, it may be difficult to uniformly disperse in the photosensitive layer coating solution.
Therefore, it is more preferable that the addition amount of the charge generating agent is set to a value within the range of 0.8 to 2.8% by weight with respect to the total amount of the photosensitive layer.

3. Dispersion aid (1) type Further, the dispersion aid is characterized by containing a quinacridone pigment as a dispersion aid.
This is because the use of such a quinacridone pigment as a dispersion aid can improve the dispersibility of the oxotitanyl phthalocyanine crystal as the charge generating agent in the photosensitive layer.
That is, due to the effect of the quinacridone pigment, dispersibility in the electrophotographic photosensitive member can be improved even with an oxotitanyl phthalocyanine crystal having relatively poor dispersibility, and the excellent charge generation ability is sufficiently exhibited. Because it can. Therefore, an electrophotographic photosensitive member having high sensitivity to exposure can be obtained.

The quinacridone pigment is preferably insoluble in an organic solvent.
The reason for this is that the particle diameter of the quinacridone pigment can be kept at a value within a predetermined range, as will be described later. As a result, the balance of compatibility between the quinacridone pigment, the oxotitanyl phthalocyanine crystal, and other components in the coating solution for the photosensitive layer is in a suitable state, and the dispersibility of the oxo titanyl phthalocyanine crystal as a charge generating agent is improved. It is because it can do.
Specific examples of such organic solvents include, for example, alcohols such as methanol, ethanol, isopropanol and butanol; aliphatic hydrocarbons such as n-hexane, octane and cyclohexane; aromatic systems such as benzene, toluene and xylene. Halogenated hydrocarbons such as hydrocarbon, dichloromethane, dichloroethane, chloroform, carbon tetrachloride, chlorobenzene; ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dioxane, dioxolane; acetone, methyl ethyl ketone, cyclohexanone, etc. Ketones; esters such as ethyl acetate and methyl acetate; dimethylformaldehyde, dimethylformamide, dimethylsulfoxide, etc. It is.
Further, among the organic solvents described above, it is more preferable that the organic solvent is insoluble in ethers, and it is more preferable that the ethers are particularly insoluble in tetrahydrofuran.
The reason for this is that the oxo titanyl phthalocyanine crystal can retain its crystal structure without being dissolved by tetrahydrofuran, so that it is a good solvent for the polycarbonate, which is a binder resin usually used for forming an electrophotographic photoreceptor. This is because tetrahydrofuran that is can be used.

  In the electrophotographic photoreceptor of the present invention, specific examples of the quinacridone pigment that is insoluble in the organic solvent that is suitably used include compounds represented by the following formulas (3) to (5) (PR209, PV19). , PR122).

(2) Average particle diameter In addition, the quinacridone pigment is particulate, and the average particle diameter of the quinacridone pigment is set to a value in the range of 30 to 150 nm.
This is because the dispersibility of the oxotitanyl phthalocyanine crystal can be further improved by setting the average particle size of the particles made of the quinacridone pigment to a value in the range of 30 to 150 nm. Moreover, it is because the dispersibility of the quinacridone pigment itself can also be improved. Therefore, as a result of improving the dispersibility of each, the sensitivity of the electrophotographic photosensitive member can be improved.
That is, if the average particle size of the particles made of quinacridone pigment is less than 30 nm, the handling of the quinacridone pigment may be difficult or the production thereof may be inefficient. On the other hand, when the average particle diameter of the particles made of quinacridone pigment exceeds 150 nm, it may be difficult to sufficiently exert the effect as a dispersion aid in the dispersion of the oxotitanyl phthalocyanine crystal. .
Therefore, the average particle size of the particles made of quinacridone pigment is more preferably set to a value within the range of 35 to 120 nm, and further preferably set to a value within the range of 40 to 60 nm.

Here, the relationship between the average particle diameter of the quinacridone pigment particles and the dispersibility of the oxo titanyl phthalocyanine crystal will be described with reference to FIG.
In FIG. 2, the horizontal axis represents the average particle diameter (nm) of the particles made of quinacridone pigment, and the vertical axis represents the sedimentation time (days) of the oxotitanyl phthalocyanine crystal.
In addition, this sedimentation test was performed using the dispersion liquid obtained by adding and dispersing 0.25 g of Y-type oxo titanyl phthalocyanine crystals, 0.15 g of quinacridone pigment, and 30 g of tetrahydrofuran into a container.
As understood from the characteristic diagram, as the average particle diameter (nm) of the particles made of quinacridone pigment becomes larger, the sedimentation time (days) becomes shorter.
More specifically, in the range where the average particle diameter (nm) of the quinacridone pigment particles is 150 nm or less, the settling time (number of days) stably maintains a value of around 6 days regardless of the change of the value. is doing. On the other hand, when the average particle diameter (nm) in the particles composed of quinacridone pigment exceeds 150 nm, it is understood that the sedimentation time (days) is abruptly shortened as the value increases. More specifically, it can be seen that when the average particle diameter (nm) of the quinacridone pigment particles is 180 nm or more, the sedimentation time (days) is 1 day or less.

Further, the relationship between the average particle diameter of the particles made of quinacridone pigment and the sensitivity of the electrophotographic photosensitive member will be described with reference to FIG.
In FIG. 3, the horizontal axis represents the characteristic particle diameter (nm) of the particles made of quinacridone pigment, and the vertical axis represents the sensitivity (V) of the electrophotographic photosensitive member.
As understood from the characteristic diagram, as the average particle diameter (nm) of the particles made of quinacridone pigment increases, the value of sensitivity (V) in the electrophotographic photosensitive member increases. In addition, it means that the sensitivity with respect to exposure is excellent, so that the value of sensitivity (V) is small.
More specifically, when the average particle diameter (nm) of the quinacridone pigment particles is 150 nm or less, the sensitivity (V) value of the electrophotographic photosensitive member increases gently as the value increases. Continued to take a value of 200V or less. On the other hand, when the average particle diameter (nm) of the particles made of quinacridone pigment exceeds 150 nm, the value of sensitivity (V) in the electrophotographic photosensitive member greatly increases as the value increases. You can see that
Therefore, from FIG. 2 and FIG. 3, the dispersibility of the oxotitanyl phthalocyanine crystal and the sensitivity in the electrophotographic photosensitive member are improved by setting the average particle diameter (nm) of the particles made of quinacridone pigment to a value of 150 nm or less. I understand.

(3) Absorbance Further, the ratio of the absorbance (A2) of the quinacridone pigment with respect to light having a wavelength of 780 nm and the absorbance of the oxotitanylphthalocyanine crystal with respect to light having a wavelength of 780 nm (A1) satisfies the following relational expression (1). Is preferred.
1.0 <A1 / A2 <10.0 (1)
This is because the ratio of the absorbance (A2) of the quinacridone pigment to light having a wavelength of 780 nm and the absorbance of the oxotitanyl phthalocyanine crystal to light having a wavelength of 780 nm (A1) satisfies the relational expression (1). This is because it is possible to suppress the light absorption of the oxotitanyl phthalocyanine crystal and to favorably maintain the charge generation efficiency of the oxo titanyl phthalocyanine crystal.
That is, the ratio (A1 / A2) between the absorbance (A2) of the quinacridone pigment with respect to light having a wavelength of 780 nm and the absorbance (A1) of light having a wavelength of 780 nm with respect to oxotitanylphthalocyanine crystal is less than 1.0. This is because the quinacridone pigment may reduce the charge generation efficiency of the oxo titanyl phthalocyanine crystal. As a result, it may be difficult to obtain excellent sensitivity in the electrophotographic photosensitive member. On the other hand, when the value (A1 / A2) exceeds 10.0, the adsorption of the quinacridone particles to the oxotitanyl phthalocyanine crystal becomes insufficient, and the dispersibility thereof decreases, resulting in the oxotitanyl phthalocyanine crystal. This is because there is a case where the charge generation ability is not fully exhibited.
Therefore, the ratio (A1 / A2) between the absorbance (A2) of the quinacridone pigment with respect to the light having a wavelength of 780 nm and the absorbance (A1) of the oxotitanyl phthalocyanine crystal with respect to the light with a wavelength of 780 nm is 2.0 to 8.0. It is more preferable to set it as the value within the range, and it is still more preferable to set it as the value within the range of 3.0-5.0.

(4) Addition amount The addition amount of the quinacridone pigment is preferably set to a value in the range of 50 to 200 parts by weight with respect to 100 parts by weight of the oxotitanyl phthalocyanine crystal as the charge generating agent.
This is because the amount of quinacridone pigment added is set to a value within the range of 50 to 200 parts by weight with respect to 100 parts by weight of oxotitanyl dirocyanine crystals as a charge generating agent, whereby the quinacridone pigment in the coating solution for the photosensitive layer is used. This is because the interaction between oxotitanyl phthalocyanine crystals can be easily controlled. In addition, it is easy to adjust the compatibility with components in the coating solution for the photosensitive layer other than the oxotitanyl phthalocyanine crystal. As a result, the dispersibility of the oxotitanyl phthalocyanine crystal can be further improved by adjusting the balance between the two.
That is, when the amount of the quinacridone pigment added is less than 50 parts by weight with respect to 100 parts by weight of the oxotitanyl phthalocyanine crystal as the charge generating agent, the dispersibility improvement effect by the quinacridone pigment may not be exhibited. On the other hand, when this value exceeds 200 parts by weight, the quinacridone pigment itself may physically inhibit the dispersion of oxotitanyl phthalocyanine crystals.
Therefore, the amount of quinacridone pigment added is more preferably set to a value in the range of 60 to 180 parts by weight with respect to 100 parts by weight of the oxotitanyl phthalocyanine crystal as the charge generating agent, and in the range of 70 to 150 parts by weight. More preferably, it is a value.

4). Type of hole transport agent (1) The hole transport agent used in the present invention is not particularly limited, and any of various conventionally known hole transport compounds can be used. In particular, benzidine compounds, phenylenediamine compounds, naphthylenediamine compounds, phenanthrylenediamine compounds, oxadiazole compounds [for example, 2,5-di (4-methylaminophenyl) -1,3,4-oxa Diazole etc.], styryl compounds [eg 9- (4-diethylaminostyryl) anthracene etc.], carbazole compounds [eg poly-N-vinylcarbazole etc.], organic polysilane compounds, pyrazoline compounds [eg 1-phenyl-3 -(P-dimethylaminophenyl) pyrazoline etc.], hydrazone compounds, triphenylamine compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazols Compounds, triazole compounds, butadiene compounds, pyrene-hydrazone compounds, acrolein compounds, carbazole-hydrazone compounds, quinoline-hydrazone compounds, stilbene compounds, stilbene-hydrazone compounds, diphenylenediamine compounds, etc. Are preferably used. These may be used alone or in combination of two or more.
In particular, the hole transport agents (HTM-A to E) represented by the following formulas (6) to (10) are all compatible with the above-described oxotitanyl phthalocyanine crystal and have a positive hole. It is preferably used as a hole transport agent having excellent transport ability.

(2) Mobility Further, the mobility of the hole transport agent is set to 5.0 × 10 ⁻⁶ to 5.0 × 10 ⁻⁴ cm ² / V / sec (concentration 30% by weight, electric field strength 3.0 × 10 ^5. It is preferable to set the value within the range (under the condition of V / cm).
This is because charge is generated by using a hole transporting agent having a mobility within the range of 5.0 × 10 ⁻⁶ to 5.0 × 10 ⁻⁴ cm ² / V / sec under such conditions. This is because the charge generated from the agent can be transported more efficiently, and the sensitivity to exposure can be further improved.
That is, if the mobility under such conditions is less than 5.0 × 10 ⁻⁶ cm ² / V / sec, the charge generated from the charge generating agent may not be able to be fully transported. . On the other hand, when the mobility under such conditions is a value exceeding 5.0 × 10 ⁻⁴ cm ² / V / sec, it is preferable to improve the sensitivity, but it is possible to obtain such a high-performance hole transport agent. This is because it may be technically and costly difficult. Further, the balance with the electron transporting ability of the electron transporting agent is lost, so that charges may remain in the photosensitive layer.
Therefore, the mobility under such conditions is more preferably set to a value within the range of 8.0 × 10 ^{−6 to} 5.0 × 10 ⁻⁵ cm ² / V / sec, and 1.0 × 10 ⁻⁵ to More preferably, the value is within the range of 2.0 × 10 ⁻⁵ cm ² / V / sec.

(3) Addition amount The addition amount of the hole transport agent is preferably set to a value within the range of 20 to 500 parts by weight with respect to 100 parts by weight of the binder resin.
This is because when the amount of the hole transporting agent added is less than 20 parts by weight, the hole transporting function in the photosensitive layer is lowered, which may adversely affect image characteristics. On the other hand, when the added amount of the hole transport agent exceeds 500 parts by weight, the dispersibility is lowered and crystallization is likely to occur.
Therefore, the amount of the hole transport agent added is more preferably set to a value within a range of 30 to 200 parts by weight, and a value within a range of 40 to 100 parts by weight with respect to 100 parts by weight of the binder resin. Is more preferable.

5). Electron Transfer Agent (1) Type As the electron transfer agent, any of various conventionally known electron transfer compounds can be used. Fluoronone compounds such as benzoquinone compounds, diphenoquinone compounds, naphthoquinone compounds, malononitrile, thiopyran compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone, such as 2,4,7-trinitro-9-fluorenone , Dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, succinic anhydride, maleic anhydride, dibromomaleic anhydride, 2,4,7-trinitrofluorenone imine compound, ethylated nitrofluorenone imine compound, tryptoanthrin Compounds, tryptoanthrinimine compounds, azafluorenone compounds, dinitropyridoquinazoline compounds, thioxanthene compounds, 2-phenyl-1,4-benzoquinone compounds, Electron-withdrawing compounds such as nyl-1,4-naphthoquinone compounds, 5,12-naphthacenequinone compounds, α-cyanostilbene compounds, nitrostilbene compounds, and salts of anion radicals and cations of benzoquinone compounds Preferably used. These may be used alone or in combination of two or more.

  Specific examples of the electron transport agent described above include electron transport agents (ETM-A to G) represented by the following formulas (11) to (17).

(2) Addition amount The addition amount of the electron transfer agent is preferably set to a value within the range of 20 to 500 parts by weight with respect to 100 parts by weight of the binder resin.
This is because, when the amount of the electron transfer agent added is less than 20 parts by weight, the sensitivity is lowered and a practical problem may occur. On the other hand, when the added amount of the electron transport agent exceeds 500 parts by weight, the electron transport agent is easily crystallized, and it may be difficult to form an appropriate film as the photosensitive layer. Therefore, it is more preferable that the addition amount of the electron transport agent is a value within a range of 30 to 200 parts by weight, and a value within a range of 40 to 100 parts by weight with respect to 100 parts by weight of the binder resin. Is more preferable.

6). Binder resin As the binder resin, for example, styrene polymer, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic polymer, styrene-acrylic copolymer, Polyethylene, ethylene-vinyl acetate copolymer, chlorinated polyethylene, polyvinyl chloride, polypropylene, vinyl chloride-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, ketone Thermoplastic resins such as resins, polyvinyl butyral resins, and polyether resins, silicone resins, epoxy resins, phenol resins, urea resins, melamine resins, and other crosslinkable thermosetting resins, and epoxy-acrylates, and Examples thereof include a photocurable resin such as urethane-acrylate. These binder resins can be used alone or in combination of two or more.
In constituting the electrophotographic photosensitive member of the present invention, a preferred binder resin is a Z-type polycarbonate resin (Resin-A) containing a structural unit represented by the following formula (18).

7). Additives In addition to the above-described components, various additives such as sensitizers, fluorene compounds, ultraviolet absorbers, plasticizers, surfactants, and leveling agents are added to the photosensitive layer. You can also. In order to improve the sensitivity of the electrophotographic photoreceptor, a sensitizer such as terphenyl, halonaphthoquinones, and acenaphthylene may be used in combination with the charge generator.

8). Thickness The thickness of the photosensitive layer is preferably set to a value in the range of 5.0 to 100 μm.
This is because, when the thickness of the photosensitive layer is less than 5.0 μm, the mechanical strength as an electrophotographic photosensitive member may be insufficient. On the other hand, when the thickness of the photosensitive layer exceeds 100 μm, it may be easily peeled off from the substrate or may be difficult to form uniformly. Accordingly, the thickness of the photosensitive layer is more preferably set to a value within the range of 10 to 80 μm, and further preferably set to a value within the range of 20 to 40 μm.

9. Substrate As the substrate on which the above-described photosensitive layer is formed, various conductive materials can be used. For example, a conductive substrate formed of a metal such as iron, aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, and brass; Examples include a substrate made of a plastic material on which a metal is deposited or laminated, or a glass substrate coated with aluminum iodide, tin oxide, indium oxide, or the like.
That is, it is only necessary that the substrate itself has conductivity or the surface of the substrate has conductivity. Further, it is preferable that the substrate has sufficient mechanical strength when used.
The shape of the substrate may be any of a sheet shape and a drum shape according to the structure of the image forming apparatus to be used.

10. Image Forming Apparatus As an image forming apparatus equipped with the electrophotographic photosensitive member according to the present invention, a structure such as the image forming apparatus 100 shown in FIG. 4 is preferably used.
Here, FIG. 4 is a schematic diagram showing the overall configuration of the image forming apparatus. Hereinafter, the operation will be described in order.
First, the electrophotographic photosensitive member 111 of the image forming apparatus 100 is rotated at a predetermined process speed (peripheral speed) in the direction indicated by the arrow A, and then the surface is charged to a predetermined potential by the charging unit 112.
Next, the exposure unit 113 exposes the surface of the electrophotographic photosensitive member 111 through a reflection mirror or the like while being light-modulated according to image information. By this exposure, an electrostatic latent image is formed on the surface of the electrophotographic photosensitive member 111.
Next, based on the electrostatic latent image, latent image development is performed by the developing unit 114. The developing means 114 stores toner, and the toner adheres corresponding to the electrostatic latent image on the surface of the electrophotographic photosensitive member 111 to form a toner image.
The recording paper 120 is conveyed to the lower part of the electrophotographic photosensitive member along a predetermined transfer conveyance path. At this time, the toner image can be transferred onto the recording material 120 by applying a predetermined transfer bias between the electrophotographic photoreceptor 111 and the transfer means 115.

Next, the recording paper 120 to which the toner image has been transferred is separated from the surface of the electrophotographic photosensitive member 111 by a separating means (not shown) and conveyed to a fixing device by a conveying belt. Next, the toner image is fixed on the surface by being heated and pressed by the fixing device, and then discharged to the outside of the image forming apparatus 100 by a discharge roller.
On the other hand, the electrophotographic photosensitive member 111 after the transfer of the toner image continues to rotate, and residual toner (adhered matter) that has not been transferred to the recording paper 120 at the time of transfer is transferred from the surface of the electrophotographic photosensitive member 111 to the cleaning device 117 of the present invention. Removed by.
In addition, in order to make the image forming apparatus compact, it is also preferable that the image forming apparatus has no neutralization unit and does not have a neutralization unit.

In the present invention, the above-described electrophotographic photosensitive member 111 includes an electron including a photosensitive layer having a single layer structure including at least a charge generating agent, a hole transporting agent, an electron transporting agent, and a binder resin on a substrate. In the photographic photoreceptor, the photosensitive layer contains a particulate quinacridone pigment represented by the above-described formulas (3) to (5) and the like, and having an average particle size in the range of 30 to 150 nm. And oxo titanyl phthalocyanine crystal as a charge generating agent.
Therefore, as described above, the electrophotographic photoreceptor 111 can exhibit excellent sensitivity to exposure.
Therefore, the image forming apparatus 100 according to the present invention can form a sufficient electrostatic latent image on the surface of the electrophotographic photosensitive member even when the electrophotographic photosensitive member 111 is rotated at a high speed. Formation is possible.

[Second Embodiment]
In the second embodiment of the present invention, an electrophotographic photoreceptor comprising a single layer photosensitive layer containing at least a charge generating agent, a hole transporting agent, an electron transporting agent, and a binder resin on a substrate. A production method, wherein a binder resin solution containing a binder resin and an organic solvent has an oxotitanyl phthalocyanine crystal as a charge generator, a hole transport agent, an electron transport agent, and an average particle size in the range of 30 to 150 nm. A step of producing a photosensitive layer coating solution for forming a photosensitive layer by dispersing particulate quinacridone pigment having a value within the range, and applying the photosensitive layer coating solution on a substrate, followed by drying, Forming a photosensitive layer, and a method for producing an electrophotographic photoreceptor.
Hereinafter, the contents already described in the first embodiment will be omitted, and the second embodiment will be described focusing on differences from the first embodiment.

1. Coating liquid preparation step A binder resin, an oxo titanyl phthalocyanine crystal as a charge generating agent, an electron transport agent, a hole transport agent, and a particulate quinacridone pigment having a predetermined average particle diameter are added to a solvent. For example, it is preferable to disperse and mix using a roll mill, a ball mill, an attritor, a paint shaker, an ultrasonic disperser or the like to obtain a coating solution.
More specifically, it is preferable to prepare a coating solution having a solid content concentration of 1 to 7% by weight. This is because when the solid content concentration of the coating liquid is less than 1% by weight, film defects may occur. On the other hand, when the solid content concentration of the coating liquid exceeds 7% by weight, layer unevenness occurs. This is because it tends to occur and it may be difficult to form a thin film having a uniform thickness as an electrophotographic photosensitive member.

Moreover, various organic solvents can be used as the solvent for preparing the coating liquid. For example, alcohols such as methanol, ethanol, isopropanol and butanol; aliphatic hydrocarbons such as n-hexane, octane and cyclohexane; aromatic hydrocarbons such as benzene, toluene and xylene, dichloromethane, dichloroethane, chloroform and tetrachloride Halogenated hydrocarbons such as carbon and chlorobenzene; ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dioxane and dioxolane; ketones such as acetone, methyl ethyl ketone and cyclohexanone; esters such as ethyl acetate and methyl acetate Class, dimethylformaldehyde, dimethylformamide, dimethylsulfoxide, etc., alone or in combination of two or more. That.
Furthermore, in order to improve the dispersibility of the electron transporting agent, the charge generating agent and the like and the smoothness on the surface of the photosensitive layer, it is also preferable to add a surfactant, a leveling agent or the like when preparing the coating solution.

2. Application Step In carrying out the application step, it is also preferable to apply the application liquid directly on the conductive substrate, or to apply it indirectly via a barrier layer.
As a coating method, it is preferable to use, for example, a spin coater, an applicator, a spray coater, a bar coater, a dip coater, a doctor blade or the like in order to form a photosensitive layer having a uniform thickness.

3. Drying process Moreover, it is preferable to dry at a drying temperature of, for example, 60 ° C. to 150 ° C. using a high-temperature dryer or a vacuum dryer in the drying step after the coating step. This is because when the drying temperature is less than 60 ° C., the drying time becomes excessively long, and it may be difficult to efficiently form a photosensitive layer having a uniform thickness. . On the other hand, if the drying temperature exceeds 150 ° C., the photosensitive layer may be thermally decomposed.

Further, in the above-described method for producing an electrophotographic photoreceptor, even when the coating solution for the photosensitive layer is stored for a long period of time, the aggregation of oxotitanyl phthalocyanine crystals as a charge generating agent in the coating solution for the photosensitive layer In addition, the dispersibility can be effectively maintained by suppressing precipitation and the like.
Therefore, since it becomes possible to manufacture the coating liquid for photosensitive layers in large quantities at once, simplification of a manufacturing process, reduction of manufacturing cost, etc. are realizable.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these description content.

[Example 1]
1. Production of electrophotographic photoreceptor 5 parts by weight of a Y-type oxotitanyl phthalocyanine crystal composed of an oxo titanyl phthalocyanine compound represented by formula (2), and a quinacridone pigment (PR209 which is insoluble in an organic solvent represented by formula (3)) 3 parts by weight of particles having an average particle size of 120 nm, 45 parts by weight of a hole transport agent (HTM-A) represented by formula (6), and an electron transport agent (ETM-) represented by formula (11) A) 30 parts by weight and 100 parts by weight of Z-type polycarbonate (Resin-A) represented by the formula (18) having a viscosity average molecular weight of 20,000 as a binder resin (TS2020 made by Teijin Chemicals Ltd.) A coating solution for the photosensitive layer was prepared by mixing and dispersing together with 800 parts by weight of tetrahydrofuran using a ball mill for 50 hours.
Next, this photosensitive layer coating solution was applied by dip coating to an aluminum drum-shaped support substrate having a diameter of 30 mm and a total length of 254 mm as a substrate. Subsequently, it was dried with hot air at 100 ° C. for 40 minutes to prepare an electrophotographic photosensitive member having a single-layer type photosensitive layer having a film thickness of 25 μm.

2. Evaluation of Electrophotographic Photoreceptor (1) Precipitation Test Further, when preparing the above-described photosensitive layer coating solution, a sedimentation test of oxotitanyl phthalocyanine crystals as a charge generating agent was performed.
That is, 0.25 g of Y-type oxotitanyl phthalocyanine crystal, 0.15 g of quinacridone pigment, and 30 g of tetrahydrofuran were weighed in a sample bottle (manufactured by Nidec Rika Glass Co., Ltd., SV50A), and a tabletop ultrasonic cleaner (Branson Co., Ltd., A dispersion was obtained by dispersing for 1 hour using Bransonic 1200). Subsequently, in this dispersion liquid, time (days) until both a Y-type oxo titanyl phthalocyanine crystal and a quinacridone pigment settle completely was measured. The obtained results are shown in Table 1.

(2) Sensitivity measurement Moreover, the sensitivity measurement of the obtained electrophotographic photoreceptor was measured under the following conditions.
That is, using a drum sensitivity tester (produced by GENTEC Co., Ltd.), the surface potential of the electrophotographic photosensitive member is charged to +800 V, and the wavelength of 780 nm is extracted from the white light of the halogen lamp using a bandpass filter. Monochromatic light (half-width 20 nm, light intensity 0.6 μJ / cm ² ) was irradiated to the electrophotographic photoreceptor surface for 50 msec. Next, the surface potential at the time when 0.35 seconds passed from the start of exposure was measured as sensitivity. Further, the measurement results were evaluated according to the following criteria. The obtained results are shown in Table 1.
A: The value of sensitivity is less than 165 (V).
A: The sensitivity value is 165 (V) or more and less than 200 (V).
X: The value of sensitivity is 200 (V) or more.

[Examples 2 to 5]
In Examples 2 to 5, as shown in Table 1, the types of particles composed of the quinacridone pigment used in producing the electrophotographic photosensitive member are compounds represented by formulas (4) and (5) (PV19, PR122). The electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the average particle diameter was changed as shown in Table 1. The obtained results are shown in Table 1.

[Comparative Example 1]
In Comparative Example 1, an electrophotographic photoreceptor was produced and evaluated in the same manner as in Example 1 except that the quinacridone pigment was not added when producing the electrophotographic photoreceptor. The obtained results are shown in Table 1.

[Comparative Examples 2-3]
In Comparative Examples 2-3, the types of particles composed of the quinacridone pigment used in the production of the electrophotographic photosensitive member are compounds represented by the formulas (3) and (4) (PR209, PV19), respectively. An electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the average particle size was changed as shown in Table 1. The obtained results are shown in Table 1.

According to the electrophotographic photosensitive member and the method for producing the same according to the present invention, the monolayer type electrophotographic photosensitive member contains a particulate quinacridone pigment having a predetermined average particle size, and an oxotitanyl phthalocyanine crystal as a charge generating agent. By using this, it has become possible to easily produce a highly sensitive electrophotographic photosensitive member.
Therefore, the electrophotographic photosensitive member of the present invention and the image forming apparatus using the same are expected to contribute to higher speed, higher image quality, and reduced manufacturing cost in the image forming apparatus.

(A)-(c) is a figure provided in order to demonstrate the structure of a single layer type electrophotographic photoreceptor. It is a figure provided in order to demonstrate the relationship between the average particle diameter of the particle | grains which consist of a quinacridone pigment, and the dispersibility of an oxo titanyl phthalocyanine crystal. It is a figure provided in order to demonstrate the relationship between the average particle diameter of the particle | grains which consist of a quinacridone pigment, and the sensitivity in an electrophotographic photoreceptor. 1 is a diagram for explaining a schematic configuration of an image forming apparatus including an electrophotographic photosensitive member according to the present invention.

Explanation of symbols

10: Single layer type electrophotographic photosensitive member 10 ': Single layer type electrophotographic photosensitive member 10 ": Single layer type electrophotographic photosensitive member 12: Base 14: Photosensitive layer 16: Barrier layer 18: Protective layer 100: Image forming apparatus 111: Electrophotographic photosensitive member 112: Charging means 113: Exposure means 114: Development means 115: Transfer means 117: Cleaning device 120: Recording paper

Claims (7)

An electrophotographic photosensitive member provided with a photosensitive layer having a single layer structure including at least a charge generating agent, a hole transporting agent, an electron transporting agent, and a binder resin on a substrate,
The photosensitive layer includes a particulate quinacridone pigment, includes an oxotitanyl phthalocyanine crystal as the charge generator, and has an average particle diameter of 30 to 150 nm in the quinacridone pigment. An electrophotographic photoreceptor.   2. The electrophotographic image according to claim 1, wherein the addition amount of the quinacridone pigment is set to a value within a range of 50 to 200 parts by weight with respect to 100 parts by weight of the oxotitanyl phthalocyanine crystal as the charge generating agent. Photoconductor. The ratio of the absorbance (A2) of the quinacridone pigment to light having a wavelength of 780 nm and the absorbance (A1) of light of the oxotitanyl phthalocyanine crystal to light having a wavelength of 780 nm satisfies the following relational expression (1). The electrophotographic photosensitive member according to claim 1.
1.0 <A1 / A2 <10.0 (1)   The electrophotographic photosensitive member according to claim 1, wherein the quinacridone pigment is insoluble in an organic solvent. The oxo titanyl phthalocyanine crystal having the following characteristics (a) and (b) or any one of the characteristics is contained as the charge generating agent. Electrophotographic photoreceptor.
(A) In the differential scanning calorimetry, there is no peak in the range of 50 to 400 ° C. other than the peak due to vaporization of the adsorbed water. (B) In the differential scanning calorimetry, except for the peak due to vaporization of the adsorbed water. , Have no peak in the range of 50-200 ° C, but have one peak in the range of 200-400 ° C The electrophotographic photosensitive member according to claim 1, wherein the charge generating agent contains an oxo titanyl phthalocyanine crystal having the following characteristics (c):
(C) After immersing in an organic solvent for 24 hours, the CuKα characteristic X-ray diffraction spectrum has a maximum peak at least at Bragg angle 2θ ± 0.2 ° = 27.2 ° and a peak at 26.2 °. Not to do A method for producing an electrophotographic photosensitive member comprising a photosensitive layer having a single layer structure including at least a charge generating agent, a hole transporting agent, an electron transporting agent, and a binder resin on a substrate,
In a binder resin solution containing the binder resin and an organic solvent, an oxotitanyl phthalocyanine crystal as the charge generator, the hole transport agent, the electron transport agent, and an average particle size within a range of 30 to 150 nm. Dispersing a particulate quinacridone pigment having a value to produce a photosensitive layer coating solution for forming the photosensitive layer; and
Applying the photosensitive layer coating solution on the substrate and then drying to form the photosensitive layer; and
A process for producing an electrophotographic photosensitive member, comprising:

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