JP2005208616A - Electrophotographic photoreceptor, process cartridge and electrophotographic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor for contact electrification superior in ghost suppression effect and hardly generating a ghost phenomenon even when mounted on a color electrophotographic device or an electrophotographic device having no discharge means, and to provide a process cartridge and an electrophotographic device having the electrophotographic photoreceptor for the contact electrification and a contact electrification means. <P>SOLUTION: V<SB>A</SB>, V<SB>B</SB>and d of the electrophotographic photoreceptor for the contact electrification satisfies (¾-600-V<SB>A</SB>¾-¾-600-V<SB>B</SB>¾)/d≤0.17, and V<SB>C</SB>satisfies -7≤-(-450-V<SB>C</SB>)≤2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic photosensitive member used as a member to be charged for contact charging means, a process cartridge having the electrophotographic photosensitive member and contact charging means, and an electrophotographic apparatus.

  In recent years, electrophotographic photoreceptors (organic electrophotographic photoreceptors) having a photosensitive layer containing an organic charge generating substance and a charge transporting substance have been widely used in electrophotographic apparatuses such as copying machines and printers. As such a photosensitive layer, from the viewpoint of durability, the charge generation layer containing the charge generation material from the support side, and the charge transport layer (hole transport layer) containing the charge transport material (hole transport material) in this order. The mainstream is a layered (normal layer) layer structure formed by laminating.

  Among charge generation materials, charge generation materials having sensitivity in the red or infrared region are used in electrophotographic photoreceptors mounted on laser beam printers and the like that have made remarkable progress in recent years, and the frequency of demand thereof is increasing. Known charge generation materials having high sensitivity in the infrared region include phthalocyanine pigments such as oxytitanium phthalocyanine, hydroxygallium phthalocyanine, and chlorogallium phthalocyanine, and azo pigments such as monoazo, bisazo, and trisazo.

  However, when a highly sensitive charge generating material is used, the amount of generated charge is large, and electrons after holes are injected into the hole transporting layer are likely to stay in the charge generating layer, thus causing memory. There was a problem. Specifically, in the output image, there is a so-called positive ghost in which the density is increased only in a portion irradiated with light during the previous rotation, or a so-called negative ghost in which the concentration is decreased only in a portion irradiated with light during the previous rotation. .

  As conventional techniques for suppressing such a ghost phenomenon, Japanese Patent Application Laid-Open No. 11-172142 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2002-091039 (Patent Document 2) include type II chlorogallium phthalocyanine as a charge generating substance. Japanese Laid-Open Patent Application No. 07-104495 (Patent Document 3) discloses a technique of incorporating an acceptor compound into a charge generation layer using oxytitanium phthalocyanine, and Japanese Unexamined Patent Application Publication No. 2000-292946. (Patent Document 4) and Japanese Patent Application Laid-Open No. 2002-296817 (Patent Document 5) disclose techniques for incorporating a dithiobenzyl compound into a charge generation layer using phthalocyanine. Japanese Patent No. 136860 (Patent Document 6) and Japanese Patent Laid-Open No. 02-136861 (Patent Document 7) Japanese Patent Laid-Open No. 02-146048 (Patent Document 8), Japanese Patent Laid-Open No. 02-146049 (Patent Document 9), Japanese Patent Laid-Open No. 02-146050 (Patent Document 10), Japanese Patent Laid-Open No. 05-150498 (Patent Document 11). ), Japanese Patent Laid-Open No. 06-313974 (Patent Document 12), and Japanese Patent Laid-Open No. 2000-039730 (Patent Document 13), there is a technique in which an electron transport material, an electron acceptor material, or an electron withdrawing material is contained in a charge generation layer. It is disclosed.

  Image formation by electrophotography forms an electrostatic latent image on the surface of the electrophotographic photosensitive member by charging the surface of the electrophotographic photosensitive member and irradiating the surface of the charged electrophotographic photosensitive member with exposure light. Then, the electrostatic latent image is developed with toner to form a toner image on the surface of the electrophotographic photosensitive member, and the toner image is transferred from the surface of the electrophotographic photosensitive member to a transfer material such as paper. It is common to be done.

  As a method for charging the surface of the electrophotographic photosensitive member, in recent years, a charging member arranged in contact with the surface of the electrophotographic photosensitive member, that is, a contact charging member is used, and the electrophotographic photosensitive member is applied by applying a voltage to the contact charging member. A system for charging the surface of the body, that is, a contact charging system is becoming mainstream. As the contact charging member, a roller-shaped charging member having an elastic layer composed of rubber and a conductive agent, so-called charging roller is frequently used.

The contact charging method has an advantage that the generation amount of nitrogen oxides and ozone is remarkably smaller than the corona charging method. In the corona charging method, about 80% of the current flowing through the corona charger flows to the shield and is wasted. However, the contact charging method has an advantage that it is economical because there is no waste.
Japanese Patent Laid-Open No. 11-172142 JP 2002-091039 A Japanese Patent Application Laid-Open No. 07-104495 JP 2000-292946 A JP 2002-296817 A Japanese Patent Laid-Open No. 02-136860 Japanese Patent Laid-Open No. 02-136861 Japanese Patent Laid-Open No. 02-146048 Japanese Patent Laid-Open No. 02-146049 Japanese Patent Laid-Open No. 02-146050 Japanese Patent Laid-Open No. 05-150498 Japanese Patent Laid-Open No. 06-313974 JP 2000-039730 A

  The development of today's electrophotographic technology is remarkable, and the electrophotographic photosensitive member is required to have more excellent characteristics.

  For example, conventionally, black and white images such as characters have been mainly used, but in recent years, demand for color images such as photographs has increased, and the demand for such image quality has been increasing year by year.

  The above-described ghost phenomenon is particularly likely to appear in a halftone image, and becomes a particularly important problem in a color image that is often an overlap of halftone images.

  In the case of a color image, even if the ghost level is the same as that of a monochrome image for each color, the ghost phenomenon is likely to be manifested by superimposing a plurality of colors.

  Further, as a method for suppressing the ghost phenomenon, there is a method of providing a static elimination means such as pre-exposure in the electrophotographic apparatus, but the static elimination means may be omitted from the viewpoint of cost reduction and miniaturization of the main body of the electrophotographic apparatus. It is getting more.

  The above prior art cannot be said to be sufficiently effective for such a harsh situation with a ghost phenomenon.

  An object of the present invention is to provide an electrophotographic photosensitive member that has an excellent ghost suppression effect and is less likely to cause a ghost phenomenon even when mounted on a color electrophotographic device or an electrophotographic device that does not have a charge eliminating unit, and the electrophotographic photosensitive member. To provide a process cartridge and an electrophotographic apparatus.

The present invention is used as a member to be charged in a contact charging means, and includes a support, a charge generation layer containing a charge generation material provided on the support, and a positive electrode provided on the charge generation layer. In an electrophotographic photoreceptor having a hole transport layer containing a hole transport material,
The surface potential of the electrophotographic photosensitive member to -600 [V] by 5 rotating the electrophotographic photosensitive member while charging the surface of the electrophotographic photosensitive member by the set charger to a predetermined charging condition C ₁ , then the surface potential of the electrophotographic photosensitive member to -150 [V] by the surface potential to irradiate a predetermined quantity of light E ₁ on the surface of the electrophotographic photosensitive member becomes -600 [V], The surface potential of the electrophotographic photosensitive member after the surface of the electrophotographic photosensitive member having a surface potential of −150 [V] is charged by the charging device set to the charging condition C ₁ is defined as V _A [V]. ,
The surface potential of the electrophotographic photosensitive member to -150 [V] by 5 rotating the electrophotographic photosensitive member while charging the surface of the electrophotographic photosensitive member by the set charger to a predetermined charging condition C ₂ , then the surface potential of the electrophotographic photosensitive member after charged by the surface potential is set to the surface of the electrophotographic photosensitive member becomes -150 [V] to the charging condition C ₁ under the same conditions charging device V _B [V]
When the thickness of the hole transport layer is d [μm],
V _A , V _B and d are represented by the following formula (I)
(| −600−V _A | − | −600−V _B |) /d≦0.17 (I)
Satisfied, and
The surface potential of the electrophotographic photosensitive member is set to a predetermined value V _CI [by rotating the electrophotographic photosensitive member five times while charging the surface of the electrophotographic photosensitive member with a charging device set to a predetermined charging condition C ₃ . to V], then the surface potential V _{CI [V]} since the electrophotographic photosensitive member surface to the light amount E ₁ and the surface potential of the electrophotographic photosensitive member specified by irradiating a light of the same quantity of The surface of the electrophotographic photosensitive member having the value V _CII [V] and the surface potential of V _CII [V] is charged by the charging device set to the charging condition C ₃ to thereby charge the electrophotographic photosensitive member. Of the electrophotographic photosensitive member after irradiating the surface of the electrophotographic photosensitive member having a surface potential of −600 [V] with a predetermined amount of light E ₂ . when the surface potential was _V C _[V] ( The surface potential of the electrophotographic photosensitive member to -600 [V] by 5 rotating the electrophotographic photosensitive member while charging the surface of the electrophotographic photosensitive member by being set to the charging condition C ₁ charging device, and then When the surface potential of the electrophotographic photosensitive member becomes −450 [V] by irradiating the surface of the electrophotographic photosensitive member having a surface potential of −600 [V] with predetermined light, the predetermined light Is E ₂ ).
V _C is the following formula (II)
−7 ≦ − (− 450−V _C ) ≦ 2 (II)
Is an electrophotographic photosensitive member characterized by satisfying the above.

  The present invention also provides a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member and contact charging means.

  According to the present invention, an electrophotographic photosensitive member that has an excellent ghost suppression effect and is less likely to cause a ghost phenomenon even when mounted on a color electrophotographic device or an electrophotographic device that does not have a static elimination unit, and the electrophotographic photosensitive member are provided. A process cartridge and an electrophotographic apparatus can be provided.

  Hereinafter, the present invention will be described in detail.

  The electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member (electrophotographic photosensitive member for contact charging) used as a member to be charged of the contact charging means.

  A determination method for determining whether or not the electrophotographic photosensitive member satisfies the above definition of the present invention (hereinafter also referred to as “determination method of the present invention”) will be described.

  The determination method of the present invention is performed in a normal temperature and normal humidity (23 ° C., 50% RH) environment.

  In FIG. 1, an example of schematic structure of the determination apparatus for enforcing the determination method of this invention is shown.

  In FIG. 1, 101 is an electrophotographic photosensitive member to be determined, 103 is a charging roller of a charging device, 104 is an exposure device including a xenon lamp, a monochromator, and an ND filter, and 104L is light (exposure light). 105 is an electrometer (potential probe) for measuring (reading) the surface potential of the electrophotographic photosensitive member. The electrophotographic photosensitive member 101 is rotationally driven in the arrow direction. FIG. 1 illustrates an electrophotographic photosensitive member having a diameter of 60 mm.

  In the determination method of the present invention, the rotation speed of the electrophotographic photosensitive member is set to a speed at which the moving speed of the surface of the electrophotographic photosensitive member becomes 30π [mm / s] (94.25 [mm / s]). .

  The charging position by the charging roller 103, the position where the light 104L is irradiated, that is, the exposure position and the potential measuring position by the electrometer 105 are 0.25 seconds between charging and light irradiation and between the light irradiation and the potential measurement. Is set to be 0.25 seconds.

In FIG. 1, since the electrophotographic photosensitive member 101 has a diameter of 60 mm,
{(30π × 0.25) / 60π} × 360 ° = 45 °
Accordingly, the angle formed between the charging position, the electrophotographic photosensitive member center, and the exposure position, and the angle formed between the exposure position, the electrophotographic photosensitive member center, and the potential measurement position are 45 ° as shown in FIG.

  FIG. 2 shows another example of a schematic configuration of a determination apparatus for carrying out the determination method of the present invention. Reference numeral 101 'denotes an electrophotographic photosensitive member to be determined, and other reference numerals are the same as those in FIG. FIG. 2 illustrates an electrophotographic photosensitive member having a diameter of 30 mm.

  As described above, in the determination method of the present invention, the rotation speed of the electrophotographic photosensitive member is such that the moving speed of the surface of the electrophotographic photosensitive member is 30π [mm / s], and the charging position, exposure The position and the potential measurement position are set so that the time between charging and light irradiation is 0.25 seconds and the time between light irradiation and potential measurement is 0.25 seconds, as shown in FIG. In addition, when the diameter of the electrophotographic photosensitive member is 30 mm, the angle formed between the charging position, the electrophotographic photosensitive member center, and the exposure position, and the angle formed between the exposure position, the electrophotographic photosensitive member center, and the potential measurement position are both 90. °.

The charging roller 103 has a low temperature and low humidity (15 ° C., 10% RH) environment, a normal temperature and normal humidity (23 ° C., 50% RH) environment, and a high temperature and high humidity (30 ° C., 80% RH) environment. A material whose resistance per 1 cm in the longitudinal direction falls within the range of 5 × 10 ^{3 to} 5 × 10 ⁴ Ω is used. This resistance is measured as follows.

  That is, the charging roller that has been left in each environment for 24 hours is brought into contact with a metal drum connected to the ground (the metal drum is pressed so that a force of 7.8 N is applied to each end of the metal drum for a total of 15.6 N, respectively. ). Next, while rotating the metal drum at a speed of 100 mm / s and rotating the charging roller by being driven, a voltage of −500 V is applied from the power source connected to the ground to the core of the charging roller to reduce the resistance value. taking measurement. The resistance of the charging roller can be calculated from the measured resistance value, the width of the contact portion at the time of measurement (nip width), and the thickness of the layer formed on the core metal of the charging roller.

  In the determination method of the present invention, when charging the surface of the electrophotographic photosensitive member, a voltage obtained by superimposing an AC voltage on a DC voltage is applied to the charging roller from a power source. Among these, the value of the DC voltage is determined according to the charging conditions described above and below. The peak-to-peak voltage of the AC voltage is 1800 V, and the frequency is 870 Hz.

  As the light 104L, monochromatic light of 780 nm obtained by separating light from a xenon lamp using a monochromator is used, and the amount of light is adjusted by an ND filter.

  Hereinafter, the determination method of the present invention will be described in more detail.

3 is a diagram for explaining the above “V _A ”, FIG. 4 is a diagram for explaining the above “V _B ”, and FIG. 5 is a diagram for explaining the above “V _C ”. . In FIG. 5, V _CII [V] is larger in absolute value than -150 [V], and V _C [V] is larger in absolute value than -450 [V]. These are all examples shown for explanation, and the present invention is not limited to these examples. In FIG 3 to 5, C1 is charged in the charging condition _{C 1,} C2 are charged in the charging condition _{C 2,} C3 is charged at charging condition _{C 3,} E1 light irradiation amount _{E 1,} E2 is the amount of light _{E 2} , D represents potential measurement.

  In the determination method of the present invention, charging the electrophotographic photosensitive member 5 times while charging the surface of the electrophotographic photosensitive member (hereinafter also referred to as “five rotation charging”) This is to eliminate them even if they remain.

Hereinafter, the charging conditions C ₁ , C ₂ and C ₃ and the light amounts E ₁ and E ₂ will be described. These charging conditions and light quantity are determined before determining whether or not the electrophotographic photosensitive member satisfies the above-mentioned regulations of the present invention.

・ Charging condition C ₁
The DC voltage value of the voltage applied to the charging roller is adjusted so that the surface potential of the electrophotographic photoconductor is -600 [V] as a result of charging the surface of the electrophotographic photoconductor to be judged five times. .

・ Light intensity E ₁
The amount of light is adjusted by the ND filter so that the surface potential (−600 [V]) of the electrophotographic photosensitive member to be determined that has been charged five times by the charging condition C ₁ is attenuated to −150 [V].

· Charging condition _{C 2}
The value of the DC voltage among the voltages applied to the charging roller is adjusted so that the surface potential of the electrophotographic photosensitive member becomes −150 [V] as a result of charging the surface of the electrophotographic photosensitive member to be judged five times. .

· Charging condition _{C 3}
The surface of the electrophotographic photosensitive member to be judged is charged five times (the surface potential is V _CI [V]), and this is irradiated with light having the same light amount as the light amount E ₁ (the surface potential is set to V _CII [V]). As a result of charging again, the value of the DC voltage among the voltages applied to the charging roller is adjusted so that the surface potential of the electrophotographic photosensitive member becomes −600 [V]. The five-rotation charging and the second charging are the same charging conditions.

・ Light intensity E ₂
As the surface potential of the 5 rotation charged determination target of the electrophotographic photosensitive member by the charging condition _{C 1} to (-600 [V]) is attenuated to -450 [V], to adjust the quantity of light by the ND filter.

  Note that “charging” and “light irradiation” in the determination method of the present invention are performed on the entire surface of the maximum image area on the surface of the electrophotographic photosensitive member.

As described above, V _A , V _B and V _{C of the} electrophotographic photosensitive member are derived.

In the above formula (I), | −600−V _A | means that the surface of an electrophotographic photosensitive member that has been exposed at the time of the previous rotation, that is, an electrophotographic photosensitive member having an exposure history, is to be charged to −600 [V]. This is an expression that means how much the actual surface potential approaches −600 [V].

As a result of experiments, the present inventors have found that the ghost level may be small even when │−600−V _A │ is large, and the ghost level may be large even when │−600−V _A │ is small. I understood.

Even if │-600-V _A │ is small, when several images are output, the negative ghost turns to a positive ghost, or even if no ghost is visible in the initial stage (first picture) After image output, positive ghosts may suddenly become apparent.

As a result of intensive studies, the present inventors have determined that the surface potential of an electrophotographic photosensitive member having no exposure history is −600 [V _A | The difference from the expression | −600−V _B | (−−600−V _A | −−−−− 600−V _B |), which means whether or not −600 [V] is approached, causes generation of ghosts, particularly generation of positive ghosts. I found out that it was influencing.

It was also found that the relationship between (| −600−V _A | − | −600−V _B |) and the ghost level differs depending on the film thickness of the hole transport layer. Specifically, the larger the thickness of the hole transport layer, the harder the positive ghost appears in the output image.

As a result of investigations based on these findings, when the film thickness of the hole transport layer is d [μm], (| −600−V _A | − | −600−V _B |) / d is 0. It was found that the ghost phenomenon can be satisfactorily suppressed if it is 17 or less, preferably 0.13 or less. When (| −600−V _A | − | −600−V _B |) / d is larger than 0.17, positive ghost is likely to occur.

Note that (| −600−V _A | − | −600−V _B |) / d is preferably 0.01 or more. If (│-600-V _A │ --- 600-V _B │) / d is smaller than 0.01, a slight negative ghost is generated in the initial stage (first sheet) or after outputting tens of thousands of images. Minor positive ghosts may occur.

In the above formula (II),-(-450-V _C ) is the surface potential of an electrophotographic photosensitive member having an exposure history by irradiating the surface with light from -600 [V] to -450 [V]. This is an expression that means how much the actual surface potential approaches -450 [V] when it is damped.

As a result of intensive studies, the present inventors have found that-(-450-V _C ) also affects the occurrence of ghost.

As a result of investigation based on this knowledge, it was found that if-(-450-V _C ) is -7 or more and 2 or less, preferably -5 or more and 2 or less, the ghost phenomenon can be satisfactorily suppressed. . When − (− 450−V _C ) is smaller than −7, negative ghost is likely to be generated from the initial stage (first sheet), and when larger than 2, the initial value is satisfied even if the above formula (I) is satisfied. Positive ghost is likely to occur from the (first sheet).

  Although details of the reason why the ghost phenomenon is suppressed by satisfying both the definition of the above formula (I) and the above formula (II) are unknown, the present inventors presume as follows: Yes.

  That is, in the case of an electrophotographic photosensitive member in which a charge generation layer and a hole transport layer are provided in this order on a support, in the portion exposed to exposure light (image exposure light), out of the charges generated in the charge generation layer, Holes are injected into the hole transport layer, and electrons should escape to the support, but the charge generation layer or the inside of the layer provided between the charge generation layer and the support and / or the interface between them If electrons stay in the hole, holes are easily injected from the support to the charge generation layer at the next charging. This causes a positive ghost.

  Further, the accumulated electrons affect the sensitivity at the time of exposure (image exposure) after the next charging, and the sensitivity increases or decreases. This causes negative ghosts or positive ghosts. In particular, the influence on the sensitivity becomes remarkable at the initial stage (first sheet).

  The ghost phenomenon occurs as a result of overlapping of these causes, and in some cases, it manifests as a positive ghost or manifests as a negative ghost. It is presumed that an electrophotographic photosensitive member satisfying both the requirements of the formula (II) can suppress the ghost phenomenon well from the initial stage (first sheet) through durability.

Further, among electrophotographic photoreceptors satisfying both the above-described formula (I) and the above-mentioned formula (II), V _X , V _AX and V _BX , defined as described later, The thickness d [μm] of the hole transport layer and m in the following approximate formula (III) consisting of the constant m and the constant n are in the range of −200 ≦ V _X ≦ −120, 1 × 10 ⁻⁴ to 2 × 10 ^An electrophotographic photoreceptor in the range of ^-3 is preferred.
(│−600−V _AX │−│−600−V _BX │) / d = m · V _X + n (III)

・ V _X and V _AX
The surface potential of the electrophotographic photosensitive member by 5 rotating the electrophotographic photosensitive member while charging the surface of the electrophotographic photosensitive member by being set to the charging condition C ₁ charging device to -600 [V], then the surface potential The surface potential of the electrophotographic photosensitive member is set to V _X [V] by irradiating light on the surface of the electrophotographic photosensitive member having a value of −600 [V], and the electrophotographic photosensitive member is set to V _X [V]. Let V _AX [V] be the surface potential of the electrophotographic photosensitive member after the surface of the photosensitive member is charged by the charging device set to the charging condition C ₁ .

・ V _X and V _BX
The surface potential of the electrophotographic photosensitive member is set to V _X [V] by rotating the electrophotographic photosensitive member 5 times while charging the surface of the electrophotographic photosensitive member with a charging device set to a predetermined charging condition C _2X . The surface potential of the electrophotographic photosensitive member after charging the surface of the electrophotographic photosensitive member having the surface potential of V _X [V] by the charging device set under the same condition as the charging condition C ₁ is _expressed as V _BX [V]. To do.

Incidentally, the same value is a _{"V X"} in _{"V X"} and the _{"V X} and _{V BX"} in the above _{"V X} and _{V AX".}

Hereinafter, the above charging condition _C2X will be described. This charging condition is also determined before determining whether or not the electrophotographic photosensitive member satisfies the above definition of the present invention.

・ Charging condition _C2X
The value of the DC voltage among the voltages applied to the charging roller is adjusted so that the surface potential of the electrophotographic photosensitive member becomes V _X [V] as a result of charging the surface of the electrophotographic photosensitive member to be judged five times. Otherwise, the charging conditions are the same as C ₁ , C ₂ and C ₃ .

  By satisfying the definition of the above formula (III), the effect of suppressing the ghost phenomenon is maintained for a longer time, and the initial (first sheet) ghost is more unlikely to occur.

When m in the above formula (III) is 2 × 10 ⁻³ or less, the present inventors have the charge generation layer, the inside of the layer provided between the charge generation layer and the support, and / or these Since the amount of electrons staying at the interface is saturated, it is presumed that the ghost phenomenon is not deteriorated by endurance use. However, if m in the above formula (III) is less than 1 × 10 ⁻⁴ , a very slight negative ghost may be seen in the initial stage (first sheet).

FIG. 6 shows an example of a graph showing the relationship between V _X and (| −600−V _AX | − | −600−V _BX |) / d. The approximate expression (III) is derived by the method of least squares.

  Next, the configuration of the electrophotographic photosensitive member of the present invention will be described.

  As described above, the electrophotographic photosensitive member of the present invention comprises a support, a charge generation layer containing a charge generation material provided on the support, and a hole transport material provided on the charge generation layer. An electrophotographic photosensitive member having a hole transport layer to be contained.

  The support may be any conductive one (conductive support), and for example, a support made of metal (alloy) such as aluminum, nickel, copper, gold, iron, aluminum alloy, and stainless steel is used. be able to. Also, the above-mentioned metal support or plastic (polyester resin, polycarbonate resin, polyimide resin, etc.) support having a layer formed of a film formed by vacuum deposition of aluminum, aluminum alloy, indium oxide-tin oxide alloy, or the like. A glass support can also be used. In addition, a support in which conductive particles such as carbon black, tin oxide particles, titanium oxide particles, and silver particles are impregnated into plastic or paper together with an appropriate binder resin, or a plastic support having a conductive binder resin, etc. Can also be used. In addition, examples of the shape of the support include a cylindrical shape and a belt shape, and a cylindrical shape is preferable.

  The surface of the support may be subjected to cutting treatment, roughening treatment (honing treatment, blasting treatment, etc.), alumite treatment, etc. for the purpose of preventing interference fringes due to scattering of laser light, etc. Chemical treatment may be performed with a solution obtained by dissolving a metal salt compound or a fluorine compound metal salt in an acidic aqueous solution mainly composed of phosphate, phosphoric acid, or tannic acid.

  The honing process includes a dry honing process and a wet honing process. The wet honing treatment is a method in which a powdery abrasive is suspended in a liquid such as water and sprayed onto the surface of the support at a high speed to roughen the surface of the support, and the surface roughness is determined by the spray pressure. , Speed, amount of abrasive, type, shape, size, hardness, specific gravity, suspension temperature and the like. The dry honing treatment is a method of roughening the surface of the support by spraying an abrasive on the surface of the support with air at a high speed, and the surface roughness can be controlled in the same manner as the wet honing treatment. As an abrasive | polishing agent used for a honing process, particles, such as a silicon carbide, an alumina, iron, a glass bead, are mentioned.

  A conductive layer may be provided between the support and the charge generation layer or an intermediate layer to be described later for the purpose of preventing interference fringes due to scattering of laser light or the like and covering the scratches on the support.

  The conductive layer can be formed by dispersing conductive particles such as carbon black, metal particles, and metal oxide particles in a binder resin. Suitable metal oxide particles include zinc oxide and titanium oxide particles. Also, barium sulfate particles can be used as the conductive particles. A conductive layer may be provided on the conductive particles.

  The volume resistivity of the conductive particles is preferably in the range of 0.1 to 1000 Ω · cm, and more preferably in the range of 1 to 1000 Ω · cm (this volume resistivity is a resistance measuring device manufactured by Mitsubishi Yuka Co., Ltd.). (This is a value obtained by measurement using Loresta AP. A measurement sample was hardened at a pressure of 49 MPa to be a coin.) The average particle diameter of the conductive particles is preferably in the range of 0.05 to 1.0 μm, more preferably in the range of 0.07 to 0.7 μm (this average particle diameter is a value measured by a centrifugal sedimentation method). .) The ratio of the conductive particles in the conductive layer is preferably in the range of 1.0 to 90% by mass, and more preferably in the range of 5.0 to 80% by mass with respect to the total mass of the conductive layer.

  Examples of the binder resin used for the conductive layer include phenol resin, polyurethane resin, polyamide resin, polyimide resin, polyamideimide resin, polyamic acid resin, polyvinyl acetal resin, epoxy resin, acrylic resin, melamine resin, and polyester resin. Can be mentioned. These can be used alone or as a mixture or copolymer of two or more. These have good adhesion to the support, improve the dispersibility of the conductive particles, and have good solvent resistance after film formation. Among these, a phenol resin, a polyurethane resin, and a polyamic acid resin are preferable.

  The thickness of the conductive layer is preferably 0.1 to 30 μm, and more preferably 0.5 to 20 μm.

The volume resistivity of the conductive layer is preferably 10 ¹³ Ω · cm or less, more preferably in the range of 10 ⁵ to 10 ¹² Ω · cm (this volume resistivity is the same as that of the conductive layer to be measured). This is a value obtained by forming a film on an aluminum plate with the same material, forming a gold thin film on this film, and measuring the current value flowing between both electrodes of the aluminum plate and the gold thin film with a pA meter. ).

  In addition, the conductive layer may contain fluorine or antimony as necessary, and a leveling agent may be added to improve the surface properties of the conductive layer.

  Further, an intermediate layer (also referred to as an undercoat layer or an adhesive layer) having a barrier function or an adhesive function may be provided between the support or the conductive layer and the charge generation layer. The intermediate layer is formed for the purpose of improving the adhesion of the photosensitive layer, improving the coating property, improving the charge injection property from the support, and protecting the photosensitive layer from electrical breakdown.

  The intermediate layer is acrylic resin, allyl resin, alkyd resin, ethyl cellulose resin, ethylene-acrylic acid copolymer, epoxy resin, casein resin, silicone resin, gelatin resin, nylon, phenol resin, butyral resin, polyacrylate resin, polyacetal resin, polyamide Imide resin, polyamide resin, polyallyl ether resin, polyimide resin, polyurethane resin, polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polysulfone resin, polyvinyl alcohol resin, polybutadiene resin, polypropylene resin, urea resin, etc. It can be formed using a material such as aluminum.

  The thickness of the intermediate layer is preferably 0.05 to 5 μm, and more preferably 0.3 to 1 μm.

  Examples of the charge generating material used in the electrophotographic photoreceptor of the present invention include azo pigments such as monoazo, disazo, and trisazo, phthalocyanine pigments such as metal phthalocyanine and nonmetal phthalocyanine, indigo pigments such as indigo and thioindigo, Perylene pigments such as perylene acid anhydride and perylene imide, polycyclic quinone pigments such as anthraquinone and pyrenequinone, squarylium dyes, pyrylium salts, thiapyrylium salts, triphenylmethane dyes, selenium, selenium-tellurium, amorphous Examples thereof include inorganic substances such as silicon, quinacridone pigments, azulenium salt pigments, cyanine dyes, xanthene dyes, quinoneimine dyes, styryl dyes, cadmium sulfide, and zinc oxide. These charge generation materials may be used alone or in combination of two or more.

  Among the various charge generation materials described above, azo pigments and phthalocyanine pigments are preferable, and phthalocyanine pigments are particularly preferable in that the ghost phenomenon is likely to occur and the present invention works more effectively while being highly sensitive.

  Among the phthalocyanine pigments, metal phthalocyanine pigments are preferable, and oxytitanium phthalocyanine, chlorogallium phthalocyanine, dichlorotin phthalocyanine, and hydroxygallium phthalocyanine are more preferable, and among these, hydroxygallium phthalocyanine is particularly preferable.

  Examples of oxytitanium phthalocyanine include crystalline oxytitanium having strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction. Phthalocyanine crystals and 9.5 °, 9.7 °, 11.7 °, 15.0 °, 23.5 °, 24.1 ° and 27 with Bragg angles 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction Crystalline oxytitanium phthalocyanine crystals having a strong peak at 3 ° are preferred.

  As chlorogallium phthalocyanine, a crystalline form of chlorogallium having strong peaks at 7.4 °, 16.6 °, 25.5 ° and 28.2 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction Phthalocyanine crystals and crystal forms of chlorogallium phthalocyanine crystals having strong peaks at 6.8 °, 17.3 °, 23.6 ° and 26.9 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction In addition, it has strong peaks at 8.7 to 9.2 °, 17.6 °, 24.0 °, 27.4 ° and 28.8 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction. Crystalline chlorogallium phthalocyanine crystals are preferred.

  As dichlorotin phthalocyanine, Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction is 8.3 °, 12.2 °, 13.7 °, 15.9 °, 18.9 ° and 28.2 °. Crystalline dichlorotin phthalocyanine crystal having strong peaks, and strong peaks at 8.5, 11.2 °, 14.5 ° and 27.2 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction Dichlorotin phthalocyanine crystals having a crystal form of 8.7 °, 9.9 °, 10.9 °, 13.1 °, 15.2 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction , 16.3 °, 17.4 °, 21.9 °, and 25.5 ° in the form of dichlorotin phthalocyanine crystals having a strong peak, or 9 with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction .2 °, 12.2 °, 13. °, 14.6 °, preferably crystalline form of dichlorotin phthalocyanine crystal having strong diffraction peaks at 17.0 ° and 25.3 °.

  Examples of hydroxygallium phthalocyanine include a hydroxygallium phthalocyanine crystal having a crystal form having strong peaks at 7.3 °, 24.9 °, and 28.1 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction, and CuKα Strong against 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 ° and 28.3 ° with Bragg angle 2θ ± 0.2 ° in characteristic X-ray diffraction Crystalline hydroxygallium phthalocyanine crystals having a peak are preferred.

  The particle size of the charge generation material is preferably 0.5 μm or less, more preferably 0.3 μm or less, and still more preferably 0.01 to 0.2 μm.

  Examples of the binder resin used for the charge generation layer include acrylic resin, allyl resin, alkyd resin, epoxy resin, diallyl phthalate resin, silicone resin, styrene-butadiene copolymer, cellulose resin, nylon, phenol resin, butyral resin, benzal. Resin, Melamine resin, Polyacrylate resin, Polyacetal resin, Polyamideimide resin, Polyamide resin, Polyallyl ether resin, Polyarylate resin, Polyimide resin, Polyurethane resin, Polyester resin, Polyethylene resin, Polycarbonate resin, Polystyrene resin, Polysulfone resin, Polyvinyl Acetal resin, polyvinyl methacrylate resin, polyvinyl acrylate resin, polybutadiene resin, polypropylene resin, methacrylic resin, urea resin Vinyl chloride - vinyl acetate copolymer, vinyl acetate resins, and vinyl chloride resins. In particular, a butyral resin is preferable. These can be used alone or as a mixture or copolymer of two or more.

  As one of methods for producing an electrophotographic photosensitive member satisfying the above-mentioned formulas (I) and (II), and further the formula (III), there is a method in which an electron transport material is contained in the charge generation layer. Can be mentioned.

  Examples of the electron transport material include fluorenone compounds such as trinitrofluorenone, imide compounds such as pyromellitic imide and naphthylimide, quinone compounds such as benzoquinone, diphenoquinone, diiminoquinone, naphthoquinone, stilbenequinone, and anthraquinone, fluorenylidene aniline, fluorene Examples include fluorenylidene compounds such as oleylidenemalononitrile, carboxylic acid anhydrides such as phthalic anhydride, cyclic sulfone compounds such as thiopyran dioxide, oxadiazole compounds, and triazole compounds. Among these, an imide compound is preferable, and a naphthalenetetracarboxylic acid diimide compound having a structure represented by the following formula (1) is particularly preferable.

In the formula (1), R ¹⁰¹ and R ¹⁰⁴ are each independently a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkyl group interrupted by an ether group, a substituted or unsubstituted alkenyl group, or an ether group. Or a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group, or a monovalent substituted or unsubstituted heterocyclic group. R ¹⁰² and R ¹⁰³ each independently represent a hydrogen atom, a halogen atom, a nitro group, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted alkoxy group.

  Examples of the alkyl group include chain alkyl groups such as a methyl group, an ethyl group, and a propyl group, and cyclic alkyl groups such as a cyclohexyl group and a cycloheptyl group. Examples of the alkenyl group include a vinyl group and an allyl group. Examples of the aryl group include a phenyl group, a naphthyl group, and an anthryl group. Examples of the aralkyl group include a benzyl group and a phenethyl group. Examples of the monovalent heterocyclic group include a hydridyl group and a fural group. Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group.

  Examples of the substituent that each of the above groups may have include an alkyl group such as a methyl group, an ethyl group, a propyl group, a cyclohexyl group, and a cycloheptyl group, an alkenyl group such as a vinyl group and an allyl group, a nitro group, Halogen atoms such as fluorine, chlorine and bromine; halogenated alkyl groups such as perfluoroalkyl groups; aryl groups such as phenyl, naphthyl and anthryl groups; aralkyl groups such as benzyl and phenethyl groups; , Alkoxy groups such as methoxy group, ethoxy group and propoxy group.

Among the naphthalenetetracarboxylic acid diimide compounds having the structure represented by the above formula (1), at least one of R ¹⁰¹ and R ¹⁰⁴ is a substituted or unsubstituted linear alkyl group or a substituted aryl group Is preferred. Among the substituted or unsubstituted linear alkyl groups, a halogen atom-substituted linear alkyl group is preferable, and among the substituted aryl groups, a halogen atom-substituted aryl group, an alkyl group-substituted aryl group, or A halogenated alkyl group-substituted aryl group is preferred. The naphthalenetetracarboxylic acid diimide compound having the structure represented by the above formula (1) has an asymmetric structure from the viewpoint of solubility in a solvent (for example, R ¹⁰¹ and R ¹⁰⁴ are different groups). ) Is preferred.

  As the electron transport material to be contained in the charge generation layer, those having a reduction potential (reduction potential by a saturated calomel electrode) in the range of −0.80 to 0.00V are preferable, and in particular, −0.65 to −0. What is in the range of 25V is more preferable, and what is in the range of -0.60--0.25V is still more preferable.

  Specific examples of the naphthalenetetracarboxylic acid diimide compound having the structure represented by the above formula (1) are given below, but the present invention is not limited to these.

The reduction potentials of the naphthalenetetracarboxylic acid diimide compounds having the structures represented by the above formulas (1-1) to (1-13) are as follows.
(1-1): -0.59V
(1-2): -0.51V
(1-3): -0.58V
(1-4): -0.46V
(1-5): -0.48V
(1-6): -0.47V
(1-7): -0.58V
(1-8): -0.58V
(1-9): -0.57V
(1-10): -0.49V
(1-11): -0.59V
(1-12): -0.45V
(1-13): -0.59V

  The ratio of the electron transport material in the charge generation layer is preferably 10 to 60% by mass, and more preferably 21 to 40% by mass with respect to the charge generation material in the charge generation layer.

  The charge generation layer can be formed by applying a charge generation layer and, if necessary, a charge generation layer coating solution obtained by dispersing an electron transport material together with a binder resin and a solvent, and drying the coating solution. Examples of the dispersion method include a method using a homogenizer, an ultrasonic disperser, a ball mill, a sand mill, a roll mill, a vibration mill, an attritor, a liquid collision type high-speed disperser, and the like. The ratio between the charge generating material and the binder resin is preferably in the range of 1: 0.5 to 1: 4 (mass ratio).

  The solvent used in the coating solution for the charge generation layer is selected from the solubility and dispersion stability of the binder resin and charge generation material to be used. As the organic solvent, alcohol, sulfoxide, ketone, ether, ester, aliphatic Examples thereof include halogenated hydrocarbons and aromatic compounds.

  The film thickness of the charge generation layer is preferably 5 μm or less, more preferably 0.01 to 2 μm, even more preferably 0.05 to 0.3 μm.

  In addition, various sensitizers, antioxidants, ultraviolet absorbers, plasticizers, and the like can be added to the charge generation layer as necessary.

  Examples of the hole transport material used in the electrophotographic photosensitive member of the present invention include triarylamine compounds, hydrazone compounds, styryl compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, triarylmethane compounds and the like. . These hole transport materials may be used alone or in combination of two or more.

  Examples of the binder resin used for the hole transport layer include acrylic resin, acrylonitrile resin, allyl resin, alkyd resin, epoxy resin, silicone resin, nylon, phenol resin, phenoxy resin, butyral resin, polyacrylamide resin, and polyacetal resin. , Polyamideimide resin, polyamide resin, polyallyl ether resin, polyarylate resin, polyimide resin, polyurethane resin, polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polystyrene resin, polysulfone resin, polyvinyl butyral resin, polyphenylene oxide resin, polybutadiene Examples thereof include resins, polypropylene resins, methacrylic resins, urea resins, vinyl chloride resins, and vinyl acetate resins. In particular, polyarylate resin, polycarbonate resin and the like are preferable. These can be used alone or as a mixture or copolymer of two or more.

  The hole transport layer can be formed by applying a hole transport layer coating solution obtained by dissolving a hole transport material and a binder resin in a solvent, and drying it. The ratio of the hole transport material and the binder resin is preferably in the range of 2: 1 to 1: 2 (mass ratio).

  Solvents used in the coating solution for the hole transport layer include ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, ethers such as 1,4-dioxane and tetrahydrofuran. , Hydrocarbons substituted with halogen atoms such as chlorobenzene, chloroform and carbon tetrachloride are used.

  The thickness of the hole transport layer is preferably 1 to 50 μm, and more preferably 3 to 30 μm.

  In addition, an antioxidant, an ultraviolet absorber, a plasticizer, and the like can be added to the hole transport layer as necessary.

  A protective layer intended to protect the hole transport layer may be provided on the hole transport layer. The protective layer can be formed by applying a protective layer coating solution obtained by dissolving a binder resin in a solvent and drying the coating solution. Alternatively, the protective layer may be formed by applying a protective layer coating solution obtained by dissolving a binder resin monomer / oligomer in a solvent and then curing and / or drying. For curing, light, heat, or radiation (such as an electron beam) can be used.

  The various resins described above can be used as the binder resin for the protective layer.

  The thickness of the protective layer is preferably 0.5 to 10 μm, and particularly preferably 1 to 5 μm.

  When applying the coating liquid for each of the above layers, for example, a coating method such as a dip coating method (dip coating method), a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, a blade coating method, or the like should be used. Can do.

  FIG. 7 shows an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.

  In FIG. 7, reference numeral 1 denotes a cylindrical electrophotographic photosensitive member, which is driven to rotate about a shaft 2 in the direction of an arrow at a predetermined peripheral speed.

  The surface of the electrophotographic photosensitive member 1 to be rotated is uniformly charged to a predetermined positive or negative potential by contact charging means 3 having a contact charging member (charging roller or the like), and then subjected to slit exposure or laser beam scanning exposure. The exposure light (image exposure light) 4 output from exposure means (not shown) such as is received. In this way, electrostatic latent images corresponding to the target image are sequentially formed on the surface of the electrophotographic photosensitive member 1.

  The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is developed with toner contained in the developer of the developing means 5 to become a toner image. Next, the toner image formed and supported on the surface of the electrophotographic photoreceptor 1 is transferred from a transfer material supply means (not shown) to the electrophotographic photoreceptor 1 and the transfer means by a transfer bias from a transfer means (transfer roller or the like) 6. 6 (contact portion) is sequentially transferred onto a transfer material (paper or the like) P taken out and fed in synchronization with the rotation of the electrophotographic photosensitive member 1.

  The transfer material P that has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member 1 and introduced into the fixing means 8 to receive the image fixing, and is printed out as an image formed product (print, copy). Is done.

  The surface of the electrophotographic photosensitive member 1 after the transfer of the toner image is cleaned by a cleaning means (cleaning blade or the like) 7 to remove the developer (toner) remaining after transfer, and further from a pre-exposure means (not shown). After being subjected to charge removal processing by pre-exposure light (not shown), it is repeatedly used for image formation. In addition, when the charging unit is a contact charging unit as in the present invention, pre-exposure is not always necessary.

  The above-described electrophotographic photosensitive member 1 and contact charging means 3 are housed in a container and integrally coupled as a process cartridge, and the process cartridge is detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. It may be configured. In FIG. 7, the electrophotographic photosensitive member 1, the contact charging means 3, the developing means 5 and the cleaning means 7 are integrally supported to form a cartridge, and the electrophotographic apparatus is electrophotographic using a guide means 10 such as a rail of the electrophotographic apparatus main body. The process cartridge 9 is detachable from the apparatus main body.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to these. In the examples, “part” means “part by mass”.

(Example 1)
The surface of an aluminum cylinder having a diameter of 46.7 mm and a length of 260.5 mm was subjected to a wet honing treatment and subjected to ultrasonic water cleaning as a support.

  Next, an intermediate layer coating solution was prepared by dissolving 5 parts of N-methoxymethylated 6 nylon in 95 parts of methanol.

  This intermediate layer coating solution was dip-coated on a support and dried at 100 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.5 μm.

  Next, Bragg angles 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction of 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 ° and 28. 10 parts of crystalline hydroxygallium phthalocyanine crystal (charge generation material) having a strong peak at 3 °, 0.1 part of a compound having a structure represented by the following formula (2),

5 parts of polyvinyl butyral resin (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 250 parts of cyclohexanone are dispersed in a sand mill using glass beads having a diameter of 1 mm for 4 hours. 3 parts of a compound having the structure represented by (3) (electron transport material, reduction potential: −0.47 V)

Then, 250 parts of ethyl acetate was added to prepare a charge generation layer coating solution.

  This charge generation layer coating solution was dip coated on the intermediate layer and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.16 μm.

  Next, 10 parts of a compound (hole transport material) having a structure represented by the following formula (4),

And 10 parts of a polyarylate resin having a repeating structural unit represented by the following formula (5) (weight average molecular weight: 115000, molar ratio of terephthalic acid skeleton to isophthalic acid skeleton: terephthalic acid skeleton / isophthalic acid skeleton = 50/50)

Was dissolved in a mixed solvent of 50 parts of monochlorobenzene / 30 parts of dichloromethane to prepare a coating solution for a hole transport layer.

  This hole transport layer coating solution was dip coated on the charge generation layer and dried at 120 ° C. for 1 hour to form a hole transport layer having a thickness of 17 μm.

  Thus, an electrophotographic photosensitive member having a support, an intermediate layer, a charge generation layer, and a hole transport layer in this order, and the hole transport layer being a surface layer was produced.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photosensitive member was mounted on the following evaluation apparatus, and an image was output under the conditions of dark part potential −600V and light part potential −150V, and the output image was evaluated.

Evaluation Device The evaluation device used in Example 1 is a laser beam printer “manufactured by Hewlett-Packard Co., Ltd.” that does not have a charge removal device at a position upstream of the charging device and downstream of the transfer device in the rotation direction of the electrophotographic photosensitive member. Color laser jet 2500 "(process speed: 117.2 mm / s). The charging means of this laser beam printer is a contact charging means having a charging roller, and a voltage obtained by superimposing an AC voltage on a DC voltage is applied to the charging roller. As a modification, the amount of exposure light (image exposure light) was made variable.

-Image pattern for evaluation As an image pattern for evaluation, solid white and a ghost pattern shown in FIG. 8 were prepared. In FIG. 8, the portion 801 (black rectangle) is solid black, the portion 802 is solid white, the portion 803 is a portion where a ghost attributed to the solid black 801 may appear, and the portion 804 is a halftone (one dot Keima pattern). It is a part of.

-Initial evaluation First, one solid white image was output, and then 12 images of a ghost pattern were output. Of the 12 images of the ghost pattern, the first and twelfth images were evaluated. For evaluation of the ghost, a spectral densitometer X-Rite 504/508 manufactured by X-Rite was used. In the image of the ghost pattern, the density obtained by subtracting the density of the halftone portion 804 from the density of the portion 803 where the ghost can appear was measured, and this measurement was performed 10 points to obtain an average value of 10 points. When the sign of the value is +, it means a positive ghost, and when it is-, it means a negative ghost. The evaluation results are shown in Table 2.

-Evaluation after durability After the initial evaluation, 10,000 images having a density of 10% were output, and then the same evaluation as described above was performed again. The evaluation results are shown in Table 2.

  The initial evaluation and the post-endurance evaluation were performed under two environments: a normal temperature and normal humidity (23 ° C., 50% RH) environment and a low sound low humidity (15 ° C., 10% RH) environment.

(Example 2)
In Example 1, 3 parts of the compound (electron transport material) having the structure represented by the above formula (3) used in the charge generation layer was replaced with the compound having the structure represented by the following formula (6) (electron transport material, reduction potential). : -0.49V) 3 parts

An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the above was changed.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 3)
In Example 1, 3 parts of the compound (electron transport material) having the structure represented by the above formula (3) used in the charge generation layer was replaced with the compound having the structure represented by the following formula (7) (electron transport material, reduction potential). : -0.51V) 3 parts

An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the above was changed.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

Example 4
An aluminum cylinder having a diameter of 46.7 mm and a length of 260.5 mm was used as a support.

  Next, 50 parts of titanium oxide particles coated with tin oxide containing 10% by mass of antimony oxide, 25 parts of resol type phenol resin, 30 parts of methoxypropanol, 30 parts of methanol and silicone oil (polydimethylsiloxane polyoxyalkylene copolymer) , Weight average molecular weight: 3000) 0.002 part was dispersed in a sand mill using glass beads having a diameter of 1 mm for 2 hours to prepare a coating solution for a conductive layer.

  This conductive layer coating solution was dip-coated on a support and cured at 140 ° C. for 20 minutes to form a conductive layer having a thickness of 20 μm.

  Next, an intermediate layer coating solution was prepared by dissolving 5 parts of N-methoxymethylated 6 nylon in 95 parts of methanol.

  This intermediate layer coating solution was dip coated on the conductive layer and dried at 100 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.5 μm.

  Next, the Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction is 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 ° and 28. 10 parts of a crystalline hydroxygallium phthalocyanine crystal (charge generating substance) having a strong peak at 3 °, 0.1 part of a compound having a structure represented by the above formula (2), polyvinyl butyral resin (trade name: ESREC BX-1) 5 parts of Sekisui Chemical Co., Ltd.) and 250 parts of cyclohexanone were dispersed for 4 hours in a sand mill using glass beads having a diameter of 1 mm, and a compound having a structure represented by the following formula (8) ( Electron transport material, reduction potential: -0.52 V) 3 parts

Then, 250 parts of ethyl acetate was added to prepare a charge generation layer coating solution.

  This charge generation layer coating solution was dip coated on the intermediate layer and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.16 μm.

  Next, 10 parts of a compound (hole transport material) having a structure represented by the above formula (4) and 10 parts of a polycarbonate resin (weight average molecular weight: 20000) having a repeating structural unit represented by the following formula (9)

Was dissolved in a mixed solvent of 50 parts of monochlorobenzene / 30 parts of dichloromethane to prepare a coating solution for a hole transport layer.

  This hole transport layer coating solution was dip coated on the charge generation layer and dried at 120 ° C. for 1 hour to form a hole transport layer having a thickness of 20 μm.

  Thus, an electrophotographic photosensitive member having a support, a conductive layer, an intermediate layer, a charge generation layer, and a hole transport layer in this order, and the hole transport layer being a surface layer was produced.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 5)
In Example 4, 3 parts of the compound (electron transport material) having the structure represented by the above formula (8) used for the charge generation layer was replaced with the compound having the structure represented by the following formula (10) (electron transport material, reduction potential). : -0.52V) 3 parts

An electrophotographic photosensitive member was produced in the same manner as in Example 4 except that the above was changed.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 6)
In Example 1, 3 parts of the compound (electron transport material) having the structure represented by the above formula (3) used in the charge generation layer was replaced with the compound having the structure represented by the following formula (11) (electron transport material, reduction potential). : -0.60V) 3 parts

The electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the film thickness of the hole transport layer was changed from 17 μm to 20 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 7)
In Example 1, 3 parts of the compound (electron transport material) having the structure represented by the above formula (3) used for the charge generation layer was replaced with the compound having the structure represented by the following formula (12) (electron transport material, reduction potential). : -0.60V) 3 parts

The electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the film thickness of the hole transport layer was changed from 17 μm to 20 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 8)
In Example 1, 3 parts of the compound (electron transport material) having the structure represented by the above formula (3) used in the charge generation layer was replaced with the compound having the structure represented by the following formula (13) (electron transport material, reduction potential). : -0.25V) 2.2 parts

The electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the film thickness of the hole transport layer was changed from 17 μm to 20 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

Example 9
In Example 1, 3 parts of the compound (electron transport material) having the structure represented by the above formula (3) used in the charge generation layer was replaced with the compound having the structure represented by the following formula (14) (electron transport material, reduction potential). : -0.54V) 2.2 parts

The electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the film thickness of the hole transport layer was changed from 17 μm to 20 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 10)
In Example 1, the amount of the compound (electron transporting material) having the structure represented by the above formula (3) used in the charge generation layer was changed from 3 parts to 2.5 parts, and the above used in the hole transporting layer. 10 parts of the polyarylate resin having a repeating structural unit represented by the formula (5) is changed to 10 parts of a polycarbonate resin having a repeating structural unit represented by the above formula (9), and the film thickness of the hole transport layer is changed from 17 μm to 20 μm. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the above was changed.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 11)
In Example 1, the amount of the compound (electron transport material) having the structure represented by the above formula (3) used for the charge generation layer was changed from 3 parts to 4 parts, and the above formula ( 5 parts of polyarylate resin having the repeating structural unit shown in 5) is changed to 10 parts of polycarbonate resin having the repeating structural unit shown in the above formula (9), and the film thickness of the hole transport layer is changed from 17 μm to 20 μm. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 12)
In Example 1, the amount of the compound (electron transport material) having the structure represented by the above formula (3) used for the charge generation layer was changed from 3 parts to 6 parts, and the above formula ( 5 parts of polyarylate resin having the repeating structural unit shown in 5) is changed to 10 parts of polycarbonate resin having the repeating structural unit shown in the above formula (9), and the film thickness of the hole transport layer is changed from 17 μm to 20 μm. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 13)
In Example 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the film thickness of the charge generation layer was changed from 0.16 μm to 0.12 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 14)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the thickness of the charge generation layer was changed from 0.16 μm to 0.20 μm in Example 1.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 15)
In Example 4, the electrophotographic photosensitive layer was changed in the same manner as in Example 4 except that the thickness of the charge generation layer was changed from 0.16 μm to 0.18 μm and the thickness of the hole transport layer was changed from 20 μm to 13 μm. The body was made.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 16)
In Example 4, an electrophotographic photosensitive member was produced in the same manner as in Example 4 except that the thickness of the charge generation layer was changed from 0.16 μm to 0.08 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 17)
An electrophotographic photosensitive member was produced in the same manner as in Example 4 except that the thickness of the charge generation layer was changed from 0.16 μm to 0.20 μm in Example 4.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 18)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the film thickness of the hole transport layer was changed from 17 μm to 14 μm in Example 1.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 19)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the film thickness of the hole transport layer was changed from 17 μm to 25 μm in Example 1.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 20)
In Example 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the intermediate layer was formed as follows.

  That is, 10 parts of a resin having a repeating structural unit represented by the following formula (15) (weight average molecular weight: 12000),

An intermediate layer coating solution was prepared by dissolving 50 parts of N, N-dimethylacetamide in 50 parts of tetrahydrofuran.

  This intermediate layer coating solution was dip-coated on a support and dried at 180 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.8 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 21)
In Example 2, an electrophotographic photosensitive member was produced in the same manner as in Example 2 except that the intermediate layer was formed as follows.

  That is, by applying 10 parts of a resin having a repeating structural unit represented by the above formula (15) (weight average molecular weight: 12000) and 50 parts of N, N-dimethylacetamide in 50 parts of tetrahydrofuran, coating for an intermediate layer is performed. A liquid was prepared.

  This intermediate layer coating solution was dip-coated on a support and dried at 180 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.8 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 22)
In Example 3, an electrophotographic photosensitive member was produced in the same manner as in Example 3 except that the intermediate layer was formed as follows.

  That is, by applying 10 parts of a resin having a repeating structural unit represented by the above formula (15) (weight average molecular weight: 12000) and 50 parts of N, N-dimethylacetamide in 50 parts of tetrahydrofuran, coating for an intermediate layer is performed. A liquid was prepared.

  This intermediate layer coating solution was dip-coated on a support and dried at 180 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.8 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 23)
In Example 10, an electrophotographic photosensitive member was produced in the same manner as in Example 10 except that the intermediate layer was formed as follows.

  That is, by applying 10 parts of a resin having a repeating structural unit represented by the above formula (15) (weight average molecular weight: 12000) and 50 parts of N, N-dimethylacetamide in 50 parts of tetrahydrofuran, coating for an intermediate layer is performed. A liquid was prepared.

  This intermediate layer coating solution was dip-coated on a support and dried at 180 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.8 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 24)
In Example 11, an electrophotographic photosensitive member was produced in the same manner as in Example 11 except that the intermediate layer was formed as follows.

  That is, by applying 10 parts of a resin having a repeating structural unit represented by the above formula (15) (weight average molecular weight: 12000) and 50 parts of N, N-dimethylacetamide in 50 parts of tetrahydrofuran, coating for an intermediate layer is performed. A liquid was prepared.

  This intermediate layer coating solution was dip-coated on a support and dried at 180 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.8 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 25)
In Example 12, an electrophotographic photosensitive member was produced in the same manner as in Example 12 except that the intermediate layer was formed as follows.

  That is, by applying 10 parts of a resin having a repeating structural unit represented by the above formula (15) (weight average molecular weight: 12000) and 50 parts of N, N-dimethylacetamide in 50 parts of tetrahydrofuran, coating for an intermediate layer is performed. A liquid was prepared.

  This intermediate layer coating solution was dip-coated on a support and dried at 180 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.8 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 26)
In Example 13, an electrophotographic photosensitive member was produced in the same manner as in Example 13 except that the intermediate layer was formed as follows.

  That is, by applying 10 parts of a resin having a repeating structural unit represented by the above formula (15) (weight average molecular weight: 12000) and 50 parts of N, N-dimethylacetamide in 50 parts of tetrahydrofuran, coating for an intermediate layer is performed. A liquid was prepared.

  This intermediate layer coating solution was dip-coated on a support and dried at 180 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.8 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 27)
In Example 14, an electrophotographic photosensitive member was produced in the same manner as in Example 14 except that the intermediate layer was formed as follows.

  That is, by applying 10 parts of a resin having a repeating structural unit represented by the above formula (15) (weight average molecular weight: 12000) and 50 parts of N, N-dimethylacetamide in 50 parts of tetrahydrofuran, coating for an intermediate layer is performed. A liquid was prepared.

  This intermediate layer coating solution was dip-coated on a support and dried at 180 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.8 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 28)
In Example 5, the intermediate layer was formed as follows, the thickness of the charge generation layer was changed from 0.16 μm to 0.12 μm, and the thickness of the hole transport layer was changed from 20 μm to 8 μm. An electrophotographic photoreceptor was produced in the same manner as Example 5 except for the above.

  That is, by applying 10 parts of a resin having a repeating structural unit represented by the above formula (15) (weight average molecular weight: 12000) and 50 parts of N, N-dimethylacetamide in 50 parts of tetrahydrofuran, coating for an intermediate layer is performed. A liquid was prepared.

  This intermediate layer coating solution was dip coated on the conductive layer and dried at 180 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.8 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 29)
In Example 6, an electrophotographic photosensitive member was produced in the same manner as in Example 6 except that the charge generation layer was formed as follows.

  That is, a crystalline oxytitanium phthalocyanine crystal having a strong peak at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction (charge) (Generating substances) 12 parts, polyvinyl butyral resin (trade name: S-REC BM-2, manufactured by Sekisui Chemical Co., Ltd.) and 80 parts of cyclohexanone are dispersed for 4 hours in a sand mill using glass beads with a diameter of 1 mm. Then, 3 parts of a compound (electron transport material) having the structure represented by the above formula (3) was dissolved therein, and then 300 parts of methyl ethyl ketone was added to prepare a coating solution for charge generation layer.

  This charge generation layer coating solution was dip coated on the intermediate layer and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.16 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Example 30)
In Example 1, the surface of an aluminum cylinder having a diameter of 30.0 mm and a length of 260.5 mm was changed to the one obtained by wet honing treatment and ultrasonic water cleaning. A photographic photoreceptor was prepared.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. However, the evaluation apparatus used in Example 1 was changed to the following, and at the time of image output, the dark part potential was set to -500 V and the light part potential was set to -150 V. The evaluation results are shown in Table 2.

Evaluation Device The evaluation device used in Example 30 is a laser beam printer “manufactured by Hewlett-Packard Co., Ltd.” that does not have a charge removal device at a position upstream of the charging device and downstream of the transfer device in the rotation direction of the electrophotographic photosensitive member. This is a modified machine (process speed: 94.2 mm / s) of “Color Laser Jet 4600”. The charging means of this laser beam printer is a contact charging means provided with a charging roller, and a voltage of only DC voltage is applied to the charging roller. As a modification, the amount of exposure light (image exposure light) was made variable.

(Example 31)
In Example 2, the surface of an aluminum cylinder having a diameter of 30.0 mm and a length of 260.5 mm was changed to the one that was wet-honed and washed with ultrasonic water in the same manner as in Example 2. A photographic photoreceptor was prepared.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 30. The evaluation results are shown in Table 2.

(Example 32)
In Example 3, the surface of an aluminum cylinder having a diameter of 30.0 mm and a length of 260.5 mm was changed to the one obtained by wet honing treatment and ultrasonic cleaning with water, and then the electron was changed in the same manner as in Example 3. A photographic photoreceptor was prepared.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) to (III) were determined as described above. Values are shown in Table 1.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 30. The evaluation results are shown in Table 2.

(Comparative Example 1)
In Example 10, an electrophotographic photosensitive member was produced in the same manner as in Example 10 except that the compound (electron transport material) having the structure represented by the above formula (3) was not contained in the charge generation layer.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) and (II) were determined as described above. Values are shown in Table 3.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.

(Comparative Example 2)
An aluminum cylinder having a diameter of 46.7 mm and a length of 260.5 mm was used as a support.

  Next, 50 parts of titanium oxide particles coated with tin oxide containing 10% by mass of antimony oxide, 25 parts of resol type phenol resin, 30 parts of methoxypropanol, 30 parts of methanol and silicone oil (polydimethylsiloxane polyoxyalkylene copolymer) , Weight average molecular weight: 3000) 0.002 part was dispersed in a sand mill using glass beads having a diameter of 1 mm for 2 hours to prepare a coating solution for a conductive layer.

  The conductive layer coating solution was dip-coated on a support and cured at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 20 μm.

  Next, an intermediate layer coating solution was prepared by dissolving 10 parts of N-methoxymethylated 6 nylon in 200 parts of methanol.

  This intermediate layer coating solution was dip coated on the conductive layer and dried at 90 ° C. for 10 minutes to form an intermediate layer having a thickness of 0.7 μm.

  Next, a crystalline oxytitanium phthalocyanine crystal having strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction ( 10 parts of charge generation material), 5% by mass (polyvinyl butyral resin concentration) solution in which polyvinyl butyral resin (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) is dissolved in cyclohexanone, and 97 parts of cyclohexanone / 3 parts of water mixed solvent is dispersed for 4 hours in a sand mill using glass beads having a diameter of 1 mm, and then 203.7 parts of cyclohexanone / 6.3 parts of water and 260 parts of cyclohexanone are added. Thus, a charge generation layer coating solution was prepared.

  This charge generation layer coating solution was dip coated on the intermediate layer and dried at 80 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

  Next, 9 parts of a compound (hole transport material) having a structure represented by the following formula (16),

1 part of a compound (hole transport material) having a structure represented by the above formula (4) and 10 parts of a polycarbonate resin (weight average molecular weight: 20000) having a repeating structural unit represented by the above formula (9) A hole transport layer coating solution was prepared by dissolving in a mixed solvent of 60 parts of chlorobenzene / 40 parts of dichloromethane.

  This hole transport layer coating solution was dip coated on the charge generation layer and dried at 115 ° C. for 1 hour to form a hole transport layer having a thickness of 22 μm.

  Thus, an electrophotographic photosensitive member having a support, a conductive layer, an intermediate layer, a charge generation layer, and a hole transport layer in this order, and the hole transport layer being a surface layer was produced.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) and (II) were determined as described above. Values are shown in Table 3.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.

(Comparative Example 3)
The surface of an aluminum cylinder having a diameter of 46.7 mm and a length of 260.5 mm was subjected to a wet honing treatment and subjected to ultrasonic water cleaning as a support.

  Next, an intermediate layer coating solution was prepared by dissolving 5 parts of N-methoxymethylated 6 nylon in 95 parts of methanol.

  This intermediate layer coating solution was dip coated on a support and dried at 100 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.6 μm.

  Next, a crystalline oxytitanium phthalocyanine crystal having strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction ( 3 parts of charge generation material), 2 parts of polyvinyl butyral resin (trade name: S-REC BM-2, manufactured by Sekisui Chemical Co., Ltd.), compound having the structure represented by the following formula (17) (electron transport material, reduction potential: -0.50V) 0.03 part,

In addition, 80 parts of cyclohexanone was dispersed in a sand mill apparatus using glass beads having a diameter of 1 mm for 4 hours, and then 115 parts of methyl ethyl ketone was added to prepare a coating solution for a charge generation layer.

  This charge generation layer coating solution was dip-coated on the intermediate layer and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.20 μm.

  Next, 10 parts of a compound (hole transport material) having a structure represented by the above formula (4) and 10 parts of a polycarbonate resin (weight average molecular weight: 20000) having a repeating structural unit represented by the above formula (9) Was dissolved in a mixed solvent of 50 parts of monochlorobenzene / 10 parts of dichloromethane to prepare a coating solution for a hole transport layer.

  This hole transport layer coating solution was dip coated on the charge generation layer and dried at 110 ° C. for 1 hour to form a hole transport layer having a thickness of 20 μm.

  Thus, an electrophotographic photosensitive member having a support, an intermediate layer, a charge generation layer, and a hole transport layer in this order, and the hole transport layer being a surface layer was produced.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) and (II) were determined as described above. Values are shown in Table 3.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.

(Comparative Example 4)
In Comparative Example 3, 0.03 part of the compound (electron transport material) having the structure represented by the above formula (17) used for the charge generation layer was replaced with the compound having the structure represented by the following formula (18) (electron transport material, Reduction potential: -0.50 V) 0.03 part

An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 3 except that the above was changed.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) and (II) were determined as described above. Values are shown in Table 3.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.

(Comparative Example 5)
In Comparative Example 3, an electrophotographic photosensitive member was produced in the same manner as in Comparative Example 3 except that the charge generation layer did not contain the compound having the structure represented by the above formula (17) (electron transport material).

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) and (II) were determined as described above. Values are shown in Table 3.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.

(Comparative Example 6)
The surface of an aluminum cylinder having a diameter of 46.7 mm and a length of 260.5 mm was subjected to a wet honing treatment and subjected to ultrasonic water cleaning as a support.

  Next, an intermediate layer coating solution was prepared by dissolving 5 parts of N-methoxymethylated 6 nylon in 95 parts of methanol.

  This intermediate layer coating solution was dip coated on a support and dried at 100 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.6 μm.

  Next, 20 parts of a bisazo pigment (charge generation material) having a structure represented by the following formula (19),

10 parts of a polycarbonate having a repeating structural unit represented by the above formula (9), 5 parts of a compound having a structure represented by the following formula (20) (electron transport material, reduction potential: −0.37 V),

Then, 150 parts of tetrahydrofuran was dispersed in a sand mill apparatus using glass beads having a diameter of 1 mm for 4 hours to prepare a charge generation layer coating solution.

  This charge generation layer coating solution was dip coated on the intermediate layer and dried at 110 ° C. for 30 minutes to form a charge generation layer having a thickness of 0.5 μm.

  Next, 10 parts of a compound having a structure represented by the following formula (21),

And the coating liquid for positive hole transport layers was prepared by dissolving 10 parts of polycarbonate which has a repeating structural unit shown by the said Formula (9) in 10 parts of tetrahydrofuran.

  This hole transport layer coating solution was dip-coated on the charge generation layer and dried at 110 ° C. for 30 minutes to form a hole transport layer having a thickness of 20 μm.

  Thus, an electrophotographic photosensitive member having a support, an intermediate layer, a charge generation layer, and a hole transport layer in this order, and the hole transport layer being a surface layer was produced.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) and (II) were determined as described above. Values are shown in Table 3.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.

(Comparative Example 7)
The surface of an aluminum cylinder having a diameter of 46.7 mm and a length of 260.5 mm was subjected to a wet honing treatment and subjected to ultrasonic water cleaning as a support.

  Next, an intermediate layer coating solution was prepared by dissolving 5 parts of N-methoxymethylated 6 nylon in 95 parts of methanol.

  This intermediate layer coating solution was dip coated on a support and dried at 100 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.6 μm.

  Next, a crystalline oxytitanium phthalocyanine crystal having strong peaks at 9.0 °, 14.2 °, 23.9 ° and 27.1 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction ( (Charge generating substance) 10 parts, compound having a structure represented by the following formula (22) (singlet oxygen quenching agent) 0.3 part,

10 parts of polyvinyl butyral resin (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 400 parts of cyclohexanone are dispersed for 5 hours in a sand mill using 1 mm diameter glass beads (400 parts). Thereafter, 400 parts of ethyl acetate was added to prepare a charge generation layer coating solution.

  This charge generation layer coating solution was dip-coated on the intermediate layer and dried at 80 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

  Next, 10 parts of a compound (hole transport material) having a structure represented by the above formula (4) and 10 parts of a polycarbonate having a repeating structural unit represented by the above formula (9) are mixed with 50 parts of monochlorobenzene / dichloromethane. A coating solution for a hole transport layer was prepared by dissolving in 10 parts of a mixed solvent.

  This hole transport layer coating solution was dip coated on the charge generation layer and dried at 110 ° C. for 1 hour to form a hole transport layer having a thickness of 20 μm.

  Thus, an electrophotographic photosensitive member having a support, an intermediate layer, a charge generation layer, and a hole transport layer in this order, and the hole transport layer being a surface layer was produced.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) and (II) were determined as described above. Values are shown in Table 3.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.

(Comparative Example 8)
The surface of an aluminum cylinder having a diameter of 46.7 mm and a length of 260.5 mm was subjected to a wet honing treatment and subjected to ultrasonic water cleaning as a support.

  Next, 8 parts of polyvinyl butyral resin (trade name: ESREC BM-2, manufactured by Sekisui Chemical Co., Ltd.) was dissolved in 152 parts of n-butyl alcohol. Next, 100 parts of a toluene solution containing 50% by mass of tributoxyzirconium acetylacetonate (trade name: ZC-540, Matsumoto Kosho), γ-aminopropyltriethoxysilane (trade name A1100, manufactured by Nippon Unicar Co., Ltd.) A solution in which 10 parts and 130 parts of n-butyl alcohol were mixed was added to a solution obtained by dissolving the polyvinyl butyral resin in n-butyl alcohol, followed by stirring to prepare an intermediate layer coating solution.

  This intermediate layer coating solution was dip-coated on a support and dried at 150 ° C. for 10 minutes to form an intermediate layer having a thickness of 1.0 μm.

  Next, chlorogallium phthalocyanine crystals having a strong peak at 7.4 °, 16.6 °, 25.5 and 28.2 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction (charges) (Generating material) 4 parts, 4 parts of vinyl chloride-vinyl acetate-maleic acid copolymer (manufactured by Union Carbide), and 100 parts of acetic acid-n-butyl in a dynomill apparatus using glass beads having a diameter of 1 mm for 12 hours By dispersing, a coating solution for a charge generation layer was prepared.

  This charge generation layer coating solution was dip-coated on the intermediate layer and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.25 μm.

  Next, 4 parts of N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (hole transport material), and the above A coating solution for a hole transport layer was prepared by dissolving 6 parts of a polycarbonate resin having a repeating structural unit represented by the formula (9) in 40 parts of monochlorobenzene.

  This hole transport layer coating solution was dip-coated on the charge generation layer and dried at 120 ° C. for 40 minutes to form a hole transport layer having a thickness of 20 μm.

  Thus, an electrophotographic photosensitive member having a support, an intermediate layer, a charge generation layer, and a hole transport layer in this order, and the hole transport layer being a surface layer was produced.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) and (II) were determined as described above. Values are shown in Table 3.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.

(Comparative Example 9)
The surface of an aluminum cylinder having a diameter of 46.7 mm and a length of 260.5 mm was subjected to a wet honing treatment and subjected to ultrasonic water cleaning as a support.

  Next, an intermediate layer coating solution was prepared by dissolving 5 parts of N-methoxymethylated 6 nylon in 95 parts of methanol.

  This intermediate layer coating solution was dip coated on a support and dried at 100 ° C. for 20 minutes to form an intermediate layer having a thickness of 0.6 μm.

  Next, chlorogallium phthalocyanine crystals having a strong peak at 7.4 °, 16.6 °, 25.5 and 28.2 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction (charges) (Generating material) 10 parts, 10 parts of vinyl chloride-vinyl acetate copolymer (manufactured by Union Carbide) and 200 parts of acetic acid-n-butyl were dispersed in a sand mill using glass beads having a diameter of 1 mm for 3 hours. 1 part of a compound having a structure represented by the following formula (23) (hole transport material)

Was added and dispersed for 1 hour to prepare a coating solution for charge generation layer.

  This charge generation layer coating solution was dip-coated on the intermediate layer and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

  Next, 10 parts of a compound (hole transport material) having a structure represented by the above formula (23) and 10 parts of a polycarbonate having a repeating structural unit represented by the above formula (9) are dissolved in 60 parts of monochlorobenzene. By doing so, the coating liquid for positive hole transport layers was prepared.

  This hole transport layer coating solution was dip-coated on the charge generation layer and dried at 110 ° C. for 1 hour to form a hole transport layer having a thickness of 25 μm.

  Thus, an electrophotographic photosensitive member having a support, an intermediate layer, a charge generation layer, and a hole transport layer in this order, and the hole transport layer being a surface layer was produced.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) and (II) were determined as described above. Values are shown in Table 3.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.

(Comparative Example 10)
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 1 except that the thickness of the charge generation layer was changed from 0.16 μm to 0.3 μm in Comparative Example 1.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) and (II) were determined as described above. Values are shown in Table 3.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.

(Comparative Example 11)
In Example 7, an electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the thickness of the charge generation layer was changed from 0.16 μm to 0.12 μm.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) and (II) were determined as described above. Values are shown in Table 3.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.

(Comparative Example 12)
An electrophotographic photosensitive member was produced in the same manner as in Example 6.

  With respect to the produced electrophotographic photoreceptor, the parameters according to the above formulas (I) and (II) were determined as described above. Values are shown in Table 3.

  The produced electrophotographic photoreceptor was evaluated in the same manner as in Example 1. However, the evaluation apparatus used in Example 1 was changed to the following, and at the time of image output, the dark part potential was set to -500 V and the light part potential was set to -150 V. The evaluation results are shown in Table 4.

Evaluation Device The evaluation device used in Comparative Example 12 is a laser beam printer “manufactured by Hewlett-Packard Co., Ltd.” that does not have a charge removal device at a position upstream of the charging device and downstream of the transfer device in the rotation direction of the electrophotographic photosensitive member. Color laser jet 2500 "(process speed: 117.2 mm / s). As a modification, the charging means was changed to a corona charging means equipped with a corona discharger, and the amount of exposure light (image exposure light) was variable.

  When the 10-point average value of the density obtained by subtracting the density of the halftone part 804 from the density of the part 803 where the ghost can appear is determined to be not sufficient, the effect of the present invention is not sufficiently obtained. .

As is apparent from Tables 2 and 4, Comparative Examples 1, 8 to 10 have (| −600−V _A | − | −600−V _B |) / d larger than 0.17, so that the ghost after durability The level is bad. In Comparative Examples 2 to 5 and 7,-(-450-V _C ) is smaller than -7, so negative ghost is generated on the first sheet. In Comparative Example 6, since-(-450-V _C ) is larger than 2, positive ghost tends to occur. When Example 6 and Comparative Example 9 are compared, it can be seen that, even if _VA is an equivalent value, positive ghosts are generated after the endurance in the comparative example.

  Further, comparing Example 6 with Comparative Example 12, it can be seen that the use of contact charging means as charging means is effective in suppressing ghosts.

It is a figure which shows an example of schematic structure of the determination apparatus for enforcing the determination method of this invention. It is a figure which shows another example of schematic structure of the determination apparatus for enforcing the determination method of this invention. It is a figure for _{demonstrating} " _VA ". It is a figure for _{demonstrating} " _VB ". It is a figure for _{demonstrating} " _VC ". It is a diagram showing an example of a graph showing the relationship between V _X and _{(│-600-V AX │} -│-600-V BX │) / d. 1 is a diagram illustrating an example of a schematic configuration of an electrophotographic apparatus including a process cartridge having the electrophotographic photosensitive member of the present invention. It is an image pattern for evaluation.

Explanation of symbols

101 Electrophotographic photoreceptor (diameter 60mm)
101 'electrophotographic photosensitive member (diameter is 30 mm)
103 Charging roller 104 Exposure device 104L Light (exposure light)
105 Electrometer (potential probe)
DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Axis 3 Contact charging means 4 Exposure light (image exposure light)
DESCRIPTION OF SYMBOLS 5 Developing means 6 Transfer means 7 Cleaning means 8 Fixing means 9 Process cartridge 10 Guide means P Transfer material 801 Solid black 802 Solid white 803 Portion where ghost due to solid black 801 may appear 804 Halftone (1 dot Keima pattern)

Claims (9)

A support, a charge generation layer containing a charge generation material provided on the support, and a hole transport material provided on the charge generation layer; In an electrophotographic photoreceptor having a hole transport layer containing,
The surface potential of the electrophotographic photosensitive member to -600 [V] by 5 rotating the electrophotographic photosensitive member while charging the surface of the electrophotographic photosensitive member by the set charger to a predetermined charging condition C ₁ , then the surface potential of the electrophotographic photosensitive member to -150 [V] by the surface potential to irradiate a predetermined quantity of light E ₁ on the surface of the electrophotographic photosensitive member becomes -600 [V], The surface potential of the electrophotographic photosensitive member after the surface of the electrophotographic photosensitive member having a surface potential of −150 [V] is charged by the charging device set to the charging condition C ₁ is defined as V _A [V]. ,
The surface potential of the electrophotographic photosensitive member to -150 [V] by 5 rotating the electrophotographic photosensitive member while charging the surface of the electrophotographic photosensitive member by the set charger to a predetermined charging condition C ₂ , then the surface potential of the electrophotographic photosensitive member after charged by the surface potential is set to the surface of the electrophotographic photosensitive member becomes -150 [V] to the charging condition C ₁ under the same conditions charging device V _B [V]
When the thickness of the hole transport layer is d [μm],
V _A , V _B and d are represented by the following formula (I)
(| −600−V _A | − | −600−V _B |) /d≦0.17 (I)
Satisfied, and
The surface potential of the electrophotographic photosensitive member is set to a predetermined value V _CI [by rotating the electrophotographic photosensitive member five times while charging the surface of the electrophotographic photosensitive member with a charging device set to a predetermined charging condition C ₃ . to V], then the surface potential V _{CI [V]} since the electrophotographic photosensitive member surface to the light amount E ₁ and the surface potential of the electrophotographic photosensitive member specified by irradiating a light of the same quantity of the value V _{CII [V],} then the electrophotographic photosensitive member by the surface potential is charged by the set charger to the surface of the electrophotographic photosensitive member becomes V _{CII [V]} to the charging condition C ₃ Of the electrophotographic photosensitive member after irradiating the surface of the electrophotographic photosensitive member having a surface potential of −600 [V] with a predetermined amount of light E ₂ . when the surface potential was _V C _[V] ( The surface potential of the electrophotographic photosensitive member to -600 [V] by 5 rotating the electrophotographic photosensitive member while charging the surface of the electrophotographic photosensitive member by being set to the charging condition C ₁ charging device, and then When the surface potential of the electrophotographic photosensitive member becomes −450 [V] by irradiating the surface of the electrophotographic photosensitive member having a surface potential of −600 [V] with predetermined light, the predetermined light Is E ₂ ).
V _C is the following formula (II)
−7 ≦ − (− 450−V _C ) ≦ 2 (II)
An electrophotographic photoreceptor characterized by satisfying Wherein the surface potential of the electrophotographic photosensitive member to -600 [V] by 5 rotating said electrophotographic photosensitive member while charging the surface of the electrophotographic photosensitive member by being set to the charging condition C ₁ charging device, then, the surface potential of the electrophotographic photosensitive member to V _{X [V]} by applying light to the surface of the electrophotographic photosensitive member surface potential becomes -600 [V], the surface potential V _{X [V} The surface potential of the electrophotographic photosensitive member after charging the surface of the electrophotographic photosensitive member with the charging condition C ₁ set to V _AX [V],
The surface potential of the electrophotographic photosensitive member is set to V _X [V] by rotating the electrophotographic photosensitive member five times while charging the surface of the electrophotographic photosensitive member with a charging device set to a predetermined charging condition C _2X. Then, the surface potential of the electrophotographic photosensitive member after the surface of the electrophotographic photosensitive member having a surface potential of V _X [V] is charged by a charging device set under the same condition as the charging condition C ₁ is expressed as follows. When V _BX [V],
In the range of −200 ≦ V _X ≦ −120, V _X , V _AX , V _BX and the thickness d [μm] of the hole transport layer, and the following approximate formula (III) consisting of constant m and constant n
(│−600−V _AX │−│−600−V _BX │) / d = m · V _X + n (III)
The electrophotographic photosensitive member according to claim 1, wherein m is in the range of 1 × 10 ⁻⁴ to 2 × 10 ⁻³ . Said V _A , said V _B and said d are represented by the following formula (I) ′
(| −600−V _A | − | −600−V _B |) /d≦0.13 (I) ′
Satisfied, and the _{V C} is represented by the following formula (II) '
−5 ≦ − (− 450−V _C ) ≦ 2 (II) ′
The electrophotographic photosensitive member according to claim 1, wherein the electrophotographic photoreceptor is satisfied.   The electrophotographic photosensitive member according to claim 1, wherein the charge generation layer contains at least hydroxygallium phthalocyanine as the charge generation material.   The electrophotographic photosensitive member according to claim 1, wherein the charge generation layer contains an electron transport material.   The electrophotographic photosensitive member according to claim 5, wherein the electron transport material is a naphthalenecarboxylic acid diimide compound.   7. A process cartridge which integrally supports the electrophotographic photosensitive member according to claim 1 and a contact charging means and is detachable from an electrophotographic apparatus main body.   An electrophotographic apparatus comprising: the electrophotographic photosensitive member according to claim 1; and a contact charging unit, an exposing unit, a developing unit, and a transferring unit disposed around the electrophotographic photosensitive member. apparatus.   9. The electrophotographic apparatus according to claim 8, wherein there is no static elimination unit at a position upstream of the charging unit and downstream of the transfer unit.

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