JP2003005409A - Electrophotographic photoreceptor, and process cartridge and electrophotographic device having the electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having no spots or stripe images due to electrification failure in the electrification process by superimposing AC voltage on DC voltage and to apply the photoreceptor for practical use. SOLUTION: When the electrophotographic photoreceptor and an electrifying member are used to apply only DC voltage from the electrifying member on the photoreceptor to electrify the surface of the photoreceptor, the relation in the DC voltage Vdc (V) applied, the dark potential Vd (V) of the photoreceptor and the discharge inception voltage Vth (V) of the electrophotographic photoreceptor satisfy the formula of |Vdc|-|Vd|>|Vth|/2. The above photoreceptor has at least a photosensitive layer and a surface layer successively formed on a conductive supporting body. The hardness Hplast (N/mm<2> ) by plastic deformation on the surface protective layer satisfies the formula of 300<=Hplast<=600 (under the measurement conditions of 22 deg.C and 52% RH environment) and the capacitance C (pF/cm<2> ) of the photoreceptor per 1 cm<2> satisfies the formula of C>=140.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrophotographic photoreceptor,
More specifically, the present invention relates to an electrophotographic photosensitive member having a protective layer, a process cartridge for an electrophotographic device having the electrophotographic photosensitive member, and an electrophotographic apparatus.

[0002]

2. Description of the Related Art In the electrophotographic method, electrophotographic photoconductors such as selenium, cadmium sulfide, zinc oxide, amorphous silicon, organic photoconductors, etc. are basically used for charging, exposing, developing, transferring and fixing. Do the process.
Therefore, when obtaining an image, the charging process is
Conventionally, most of the metal wires have a high voltage (DC5-8kV)
Is applied, and charging is performed by the corona generated.
However, with this method, when corona occurs, ozone and NOx
However, there are problems that the surface of the photoconductor is deteriorated by corona products such as to cause image blurring and deterioration, and that wire stains affect the image quality and cause white spots and black streaks in the image.

In particular, an electrophotographic photosensitive member whose photosensitive layer is mainly composed of an organic photoconductor has lower chemical stability than other selenium photosensitive members and amorphous silicon photosensitive members and is exposed to corona products. If this happens, a chemical reaction (mainly an oxidation reaction) occurs and tends to deteriorate. Therefore, when it is repeatedly used under corona charging, image blur and sensitivity decrease due to the above-mentioned deterioration, and image density becomes low due to an increase in residual potential, so that the printing (copying) resistance life tends to be shortened.

In the case of corona charging, the electric current directed to the photosensitive member is only 5 to 30% of the electric power, and most of them flow to the shield plate and are inefficient as charging means. Furthermore, since the ozone concentration increases by repeating the electrophotographic process by corona charging, it has been a serious problem in providing a comfortable use environment.

Therefore, in order to compensate for such problems,
For example, JP 57-178267 A and JP 5
6-104351, JP-A-58-40566, JP-A-58-139156, and JP-A-58-1.
As proposed in Japanese Patent No. 50975, a method of contacting and charging without using a corona discharger has been studied. The method is a method in which a charging member such as a conductive elastic roller to which a direct current voltage of about 1 to 2 kV is applied from the outside is brought into contact with the surface of the photoconductor to charge the surface of the photoconductor to a predetermined potential. .

However, this direct charging method is more uneven in charging and direct
It is disadvantageous in that dielectric breakdown of the photoconductor occurs due to discharge when a voltage is applied. Here, due to the nonuniformity of charging, stripe-shaped charging unevenness occurs in a direction of a length of 2 to 200 mm and a width of 0.5 mm or less in a direction perpendicular to the moving direction of the surface to be charged, Image defects such as white streaks (a phenomenon in which white streaks appear in a solid black or halftone image) that occur in the case of the positive development method and black streaks that occur in the case of the reverse development method. A means for solving this problem has been proposed (JP-A-7-64302). surely,
As the electrostatic capacity of the electrophotographic photosensitive member increases, the above-mentioned problems of white lines and black lines disappear, and the image uniformity improves. However, in the electrophotographic photosensitive member having the surface protective layer on the photosensitive layer, the scraped amount is 1/2 to 1/1 as compared with the case where the normal charge transport layer is used as the surface layer.
Since it is reduced to about 00, it becomes difficult to remove the discharge damage. For this reason, the external additive of the toner and the like is likely to be adhered, and fusion occurs, and problems such as scratches due to the adhesion of paper dust and the like and abnormal noise due to rubbing with the cleaning blade and the like occur.

On the other hand, in order to improve the uniformity of charging,
A method has been proposed in which an AC voltage is superimposed on a DC voltage and applied to a charging member. (JP-A-63-149668). In this charging method, a pulsating voltage is obtained by superimposing an AC voltage (Vac) on a DC voltage (Vdc), and this is applied to perform uniform charging.

In this case, while maintaining the uniformity of charging, white spots in the positive development system, black spots in the reversal development system,
In order to prevent image defects such as fogging, it is necessary that the superimposed AC voltage has a peak-to-peak potential difference (Vpp) that is at least twice the discharge start voltage Vth according to Paschen's law.

However, in order to prevent image defects, when the AC voltage to be superimposed is increased, the maximum applied voltage of the pulsating current voltage causes a slight defect in the inside of the photoconductor.
Dielectric breakdown occurs due to discharge. In particular, when the photoconductor is an organic photoconductor having a low withstand voltage, this dielectric breakdown is remarkable. In this case, in the positive development method, the image is white in the longitudinal direction of the contact portion (in the width direction of the recording material), and in the reverse development method, black streaks occur. Further, since the discharge is generated in the minute voids, there is a problem that the damage to the photoconductor is large, the photoconductor is scraped a lot, the scratches are generated, and the durability is deteriorated.
For the purpose of improving such durability, a charge transfer type surface layer or a protective layer in which polytetrafluoroethylene particles are dispersed is put on the market, but it cannot be said to have sufficient durability characteristics. Therefore, many protective layers using a curable binder have been proposed in search of further durability characteristics.
For example, Japanese Patent Application Laid-Open No. 57-30846 describes a protective layer whose resistance can be controlled by adding a metal oxide as a conductive powder to a resin, and a curing layer containing a charge transport material. Many types of protective layers have also been disclosed.

However, as in the case of applying only DC, by providing the protective layer, the amount of abrasion is 1/2 to 1% as compared with the case where the normal charge transport layer is used as the surface layer.
Since it is reduced to about 1/100, it is difficult to remove the damage caused by the discharge, toner easily adheres, fusion occurs, and scratches due to the adhesion of paper dust and the like, cleaning blades, etc. Problems such as abnormal noise due to rubbing may occur. In addition, the peak of alternating voltage
The two-peak voltage Vpp (V) is the discharge start voltage Vth
It was also confirmed that by applying Vpp which is more than twice and as small as possible, it becomes close to the state where only DC is applied. However, under such a narrow discharge condition, the discharge tends to be unstable. In particular, under low-humidity conditions, charging failure is likely to occur, and problems such as white spot images and abnormal discharge images occur.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to have a surface protective layer having excellent durability against abrasion, and to cause abnormal noise due to fusion, scratches, rubbing against a cleaning blade, etc. Further, even under a charging discharge condition where a small alternating voltage is superposed, it is possible to stably discharge under all environments, especially in a low humidity environment, and an electrophotographic photoconductor capable of maintaining high-quality image, and this electrophotographic photoconductor. To provide a process cartridge for an electrophotographic apparatus and an electrophotographic apparatus.

[0012]

SUMMARY OF THE INVENTION An electrophotographic photosensitive member and a charging member disposed in contact with the photosensitive member are provided, and by applying only a DC voltage from the charging member to the photosensitive member, When the surface is charged by discharge, the relationship between the DC applied voltage Vdc (V), the dark potential Vd (V) of the photoconductor, and the discharge start voltage Vth (V) is expressed by the following formula (1) | Vdc |-| Vd |> | Vth | / 2 (1)

[0013]

[Equation 7] An electrophotographic photosensitive member used in an electrophotographic apparatus satisfying D = L (film thickness μm of photosensitive member) / K (relative permittivity of photosensitive layer), wherein the photosensitive member is at least a photosensitive layer on a conductive support, and A surface protective layer is sequentially formed, and the value (N / mm ² ) of the hardness value Hplast of plastic deformation on the surface protective layer is given by the following formula (2): 300 N / mm ² ≤ Hplast ≤ 600 N / mm ² (2) Electrons which are satisfied and whose capacitance C (pF / cm ² ) per 1 cm ² of the photoconductor satisfies the following formula (3): capacitance C ≧ 140 pF / cm ² (3) A photographic photosensitive member, and an electrophotographic photosensitive member and a charging member disposed in contact with the photosensitive member, and a voltage obtained by superimposing an alternating voltage on a DC voltage from the charging member is applied to the photosensitive member. When the surface of the photoconductor is charged by discharge by Over click-to-peak voltage Vpp (V) is the following formula (4) 2 × Vth ≦ Vpp ≦ 2 × Vth + 400 (V) (4)

[0014]

[Equation 8] In an electrophotographic photosensitive member used in an electrophotographic apparatus satisfying D = L (film thickness μm of photosensitive member) / K (relative permittivity of photosensitive layer), the photosensitive member is at least a photosensitive layer on a conductive support, and , A surface protective layer is sequentially formed, and the value (N / mm ² ) of the hardness value Hplast of plastic deformation on the surface protective layer satisfies the above formula (2), and per 1 cm ^{2 of the} photoreceptor. Capacitance C
(PF / cm ² ) satisfies the above formula (3), and an electrophotographic apparatus process cartridge and an electrophotographic apparatus having these electrophotographic photoreceptors. It was found that the above problems can be solved by doing so.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below.

The hardness value of plastic deformation in the present invention is measured by a hardness meter (H100VP, manufactured by FISCHER Co., Ltd., Germany).
-HCU). The sample was an electrophotographic photoreceptor itself in which a photosensitive layer and a surface protective layer were sequentially formed on at least a conductive support. Usually, in order to obtain an accurate hardness value of the plastic deformation of the sample film, it is necessary to measure with a film thickness of about 10 μm or more so as not to be affected by the underlying layer. It was found that the hardness value of plastic deformation depends on the hardness value. Therefore, regarding the above-mentioned problems, it was found that it is important to satisfy the formula (2) regardless of the film thickness of the photosensitive layer and the film thickness of the protective layer. The hardness of the hardness tester is measured by applying a load with a diamond indenter with a conical angle of 136 ° at the tip of a quadrangular pyramid and pushing it into the film of the protective layer up to 1 μm, and electrically detecting the pushing depth when the load is applied. Read it.

An example of the hardness value measured by the hardness meter is shown in FIG. The horizontal axis is the indentation depth 1 (μm), and the vertical axis is the load L
(MN). Point A is the measurement start point. A → B is a curve with respect to indentation of the indenter. Point B is the point when the maximum set indentation depth (about 3 μm) is reached.
The value represented by the surface area of the indentation generated at that time is the universal hardness Hu. The curve B → C is the curve for “return” after pushing the indenter. That is, this curve corresponds to the elastic component of the measurement sample. 2 corresponding to 95% and 60% of maximum load on curve BC
When you draw a straight line that passes through the points, the slope is empirically calculated by Young's modulus E
Becomes If the intersection of the straight line and the X-axis is hr ', the hardness value Hplast of plastic deformation is the indentation depth h.
It is obtained as a hardness value at r '. That is, Hplast is shown as a plastic deformation, that is, a hardness value with scratches. Therefore, as the hardness value Hplast of the plastic deformation is increased, the scratches are less likely to occur. However, when the value of Hplast is increased to some extent, toner or the like is likely to enter, and the problem of fusion occurs from that point. The hardness value H of plastic deformation in the present invention
The measuring environment of plast is 22 ° C./52% RH.

The electrostatic capacitance C on the surface of the electrophotographic photosensitive member in the present invention is generally represented by the following formula.

C = εε ₀ × S / d ε ₀ : permittivity of free space, ε: relative permittivity S: unit area, d: unit area of distance S between electrodes is 1 cm ² and is constant in the present invention. The area is assumed and can be treated as a constant, and ε ₀ is also a constant. Therefore, the value is determined by the relative dielectric constant of the film and the film thickness. The electrophotographic photosensitive member used in the present invention has at least two layers such as a photosensitive layer and a charge injection layer, and the electrostatic capacity of the electrophotographic photosensitive member is the sum of the electrostatic capacities of the respective films. Become. The electrophotographic photosensitive member used in the present invention has a charge injection blocking layer, a charge generation layer, a charge transport layer and a charge injection layer formed in this order on an aluminum support, and the support can be treated as an electrode and other layers can be treated. The sum when the capacitances are connected in series will appear in the measured value. A sample for measuring the electrostatic capacity is cut out in a form including a support in a size that can be installed in a measuring instrument of an electrophotographic photosensitive member, and a gold sample is cut on the surface of the electrophotographic photosensitive member, in the present invention, on the charge injection layer. An electrode was formed by sputtering so as to have a size of 1 cm ² to obtain a measurement sample. However, as for the material of the electrode, the material and the method for forming the electrode are not limited to these as long as they are conductive and can be used as an electrode, and the electrode area is 1 cm.
^{Even if} it is not ^2, it can be converted into 1 cm ² by calculation, and is not limited to this. Using such a sample, an impedance measuring device (YHP 419
2A) was slightly modified so that even a sample having a curvature could be measured, and measurement was performed, and the value of 1 kHz was used as the measured value. When an electrode having an electrode area of not 1 cm ² was used, it was converted per 1 cm ² and used as the measured value.

In the present invention, the electrostatic capacity C per cm ² of the surface of the electrophotographic photosensitive member is 140 pF / cm ² or more, but 170 pF / cm ² or more is preferable, and 200 pF / cm ² or more. Is more preferable. On the other hand, the upper limit of the electrostatic capacity C per 1 cm ² of the surface of the electrophotographic photosensitive member is preferably 500 (pF / cm ² ) or less.

On the other hand, considering the charging method, in the case of ideal discharge charging with only a DC voltage, the relationship between the voltage Vdc applied to the charging member and the photosensitive member surface potential Vd is as shown in the following expression (9). . | Vd | ≈ | Vdc |-| Vth | (9)

[0022]

[Equation 9] D = L (film thickness of photoconductor μm) / K (relative permittivity of photosensitive layer) This is shown in FIG. That is, the applied voltage Vd to the charging member
No discharge occurs until c (V) reaches the discharge start voltage Vth (V), the dark potential Vd (V) of the photoconductor does not rise, and V
When dc becomes larger than Vth, the dark potential of the photoconductor increases temporarily. In addition, the discharge start voltage Vth (V)
Is almost determined by the film thickness and relative permittivity of the photoconductor. However, the dark attenuation amount of the dark potential Vd is not taken into consideration.

However, even in the case of charging only with the DC voltage, there is a case where the discharge does not occur and the charging is performed only by the injection charging. At that time, the following formula (10) is obtained. | Vd | = | Vdc | (10) Therefore, in the present invention, discharge charging is predominant, and the following formula (1) is satisfied as the definition of discharge charging. | Vdc | − | Vd | <| Vth | / 2 (1) When the surface of the photoconductor is charged by discharge by applying only a DC voltage to such a charging member, the larger the electrostatic capacity of the photoconductor is, the higher the charging becomes. Is stable, as described above, but the amount of charge required to obtain the required dark potential is large, and eventually the amount of discharge current is large and the discharge damage to the photoconductor is also large. It can be expected to be disadvantageous in terms of points. However, when a photoconductor having a hardness value of plastic deformation on the protective layer in the range of the above formula (2) is used,
Contrary to the expectation, it was found that the larger the electrostatic capacity of the photoconductor, the more the above-mentioned problems are improved. In particular, it was effective in fusing under low humidity. This is because in discharge charging in which only a DC voltage is applied to the charging member, the discharge start voltage Vth decreases as the photosensitive member capacity increases, and the voltage Vdc applied to the charging member in order to obtain the necessary dark potential is reduced. Since the value can be made small, the difference between the Vdc (V) and the photoconductor dark potential Vd (V) becomes small, and the toner, which is normally positively charged, is hardly transferred to the charging member and remains around the charging member. We anticipate that the amount will be reduced, but the real reason has not yet been clarified.

On the other hand, in discharge charging in which an alternating voltage is superimposed on a direct current voltage on the charging member, in order to obtain stable charging,
As shown in FIG. 3, it is necessary to make the peak-to-peak voltage Vpp of the alternating voltage twice or more the discharge start voltage Vth. The larger the peak-to-peak voltage Vpp, the more stable charging can be performed. However, as Vpp is increased, the amount of discharge is increased and damage to the photoconductor is also increased. When a photosensitive layer on a conductive support and a photosensitive layer having a protective layer are used, especially when a curable resin is used as a resin for the protective layer, the scraped amount is extremely reduced, and damage due to discharge is prevented. It becomes difficult to remove.

Therefore, the peak-to-peak voltage Vpp (V) of the alternating voltage applied to the charging member is expressed by the above formula (4).
By satisfying the condition (1), the charging becomes stable and the charging can be performed with less damage due to discharge. That is, it is considered that the charging method is close to the charging method in which only the DC voltage is applied to the charging member. From that viewpoint, it is preferable that the peak-to-peak voltage Vpp (V) of the alternating voltage satisfies the following expression (5). 2 × Vth ≦ Vpp ≦ 2 × Vth + 300 (V) (5) Therefore, the hardness value Hplast (N / m) of plastic deformation on the protective layer
m ² ) to the above formula (2) and the electrostatic capacitance C of the photoconductor
It has been found that the above-mentioned problems can be similarly solved by using the above equation (3). Further, it has been found that in the discharge charging method in which an alternating voltage is superimposed on a DC voltage, increasing the electrostatic capacity of the photoconductor contributes to the stability of charging. Under the conditions represented by the formulas (4) and (5), in a photoreceptor having a capacity satisfying the formula (3), the entire environment, particularly a low humidity environment, and
A stable charging condition was obtained even after the durability test. However, under the conditions shown in the formulas (4) and (5), when an electrophotographic photosensitive member having a capacity not satisfying the formula (3) is used, white spots and poor charging due to poor charging under low humidity. Streaks sometimes occurred. In the present invention, the charge transport material used in the protective layer has at least one substituent selected from a hydroxyalkyl group and a hydroxyalkoxy group, and more preferably, it is described in structural formulas (1) to (3). As described above, the divalent hydrocarbon group represented by R _{1 to} R ₉ has 4 or less carbon atoms, and the number of hydroxyalkyl groups and hydroxyalkoxy groups is 2 or more.

[0026]

[Chemical 7] (In the formula, R ₁ , R ₂ , and R ₃ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and A, B, and D each represent a halogen atom or a substituent as a substituent. An alkyl group which may have, an alkoxy group which may have a substituent,
Represents an aryl group which may have a substituent, a benzene ring which may have one or more heterocyclic groups which may have a substituent,
a, b, d, m and n are 0 or 1. )

[0027]

[Chemical 8] (In the formula, R ₄ , R ₅ , and R ₆ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and E and F each have a halogen atom or a substituent as a substituent. Optionally substituted alkyl group, optionally substituted alkoxy group, optionally substituted aryl group, optionally substituted heterocyclic group benzene ring , E,
f and g are 0 or 1, p, q, and r are 0 or 1, and not all become 0 at the same time. Z ₁ and Z ₂ may have a halogen atom or a substituent, respectively. An alkyl group, an alkoxy group which may have a substituent, an aryl group which may have a substituent, and a heterocyclic group which may have a substituent are shown, and they may jointly form a ring. )

[0028]

[Chemical 9] (In the formula, R ₆ , R ₇ , R ₈ and R ₉ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and G, J,
K and L each have a halogen atom as a substituent, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an aryl group which may have a substituent, and a substituent. Represents a benzene ring which may have one or more heterocyclic groups, g, h, j, k, q, r and s are 0 or 1, and Z ₃ and Z ₄ are each a halogen atom or a substituent. An alkyl group which may have a group, an alkoxy group which may have a substituent, an aryl group which may have a substituent and a heterocyclic group which may have a substituent, and jointly form a ring. May be done. ) Further, the charge transport material contains at least one phenol residue.
It is a triphenylamine derivative represented by Structural Formulas (4) to (6), and the number of phenolic residues is 1 or more.

[0029]

[Chemical 10] (In the formula, R ₁ represents a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and R ₂ represents a hydrogen atom, an alkyl group which may have a substituent, or a substituent. Represents an optionally substituted aralkyl group or an optionally substituted phenyl group, and Ar ₁ and Ar ₂ each have an optionally substituted alkyl group, an optionally substituted aralkyl group, or an optionally substituted group. Optionally represents an aryl group or a heterocyclic group which may have a substituent, Ar ₃
Represents an arylene group which may have a divalent substituent, a heterocyclic group which may have a divalent substituent, m and n are each 0 or 1, and when n = 0, m = 0 and A
And D each have a halogen atom as a substituent, an alkyl group that may have a substituent, an alkoxy group that may have a substituent, an aryl group that may have a substituent, or a substituent. It represents a benzene ring which may have one or more good heterocyclic groups. )

[0030]

[Chemical 11] (In the formula, R ₃ represents a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and Ar ₄ and Ar ₅ each have an alkyl group which may have a substituent or a substituent which may have a substituent. Represents an aralkyl group which may have a substituent, an aryl group which may have a substituent, or a heterocyclic group which may have a substituent, and E and G each represent a halogen atom as a substituent or an alkyl which may have a substituent. Group, an alkoxy group which may have a substituent, an aryl group which may have a substituent, a benzene ring which may have one or more heterocyclic groups which may have a substituent, E And G may jointly form a ring via a substituent, and p is 0 or 1.)

[0031]

[Chemical 12] (In the formula, R ₄ and R ₅ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and Ar ₆ has an alkyl group which may have a substituent or a substituent which may have a substituent. Optionally represents an aralkyl group, an aryl group which may have a substituent, and a heterocyclic group which may have a substituent, and J, K, L, and M each represent a halogen atom or a substituent as a substituent. It may have one or more alkyl groups that may have, alkoxy groups that may have a substituent, aryl groups that may have a substituent, and heterocyclic groups that may have a substituent. Represents a benzene ring, and J and K, and L and M may jointly form a ring through a substituent, and q and r are 0 or 1, respectively.) Further, in the protective layer containing conductive particles. By doing so, the residual potential can be reduced. Further, both the conductive particles and the charge transport material may be added.

Further, in order to improve the water repellency of the surface, lubricating particles can be contained. As the lubricating particles, fluorine-containing resin particles, silicone particles, and
Examples thereof include silicon particles and alumina particles, but in the present invention, fluorine atom-containing resin particles are particularly preferable. The fluorine atom-containing resin particles include tetrafluoroethylene, trifluoroethylene chloride resin, hexafluoroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodichloroethylene resin and copolymers thereof. Of these, it is preferable to appropriately select one kind or two or more kinds, and particularly preferable are tetrafluoroethylene resin and vinylidene fluoride resin. The molecular weight of the resin particles and the particle size of the particles can be appropriately selected and are not particularly limited. Also, although inorganic particles such as silicon particles and alumina particles may not work as lubricity particles,
By dispersing and adding these, the surface roughness of the surface protective layer becomes large, the number of contact points becomes small with respect to the one in contact with the photoreceptor surface, and as a result, the lubricity of the charge injection layer increases. Are known by the present inventors. The term "lubricant particles" as used herein includes particles that impart lubricity.

As the binder resin for the protective layer used in the present invention, a curable resin is preferably used from the viewpoint of the surface hardness and abrasion resistance of the protective layer. That is, it is a resin containing a monomer or an oligomer that is cured by heat or light.

The monomer or oligomer which is cured by heat or light has, for example, a functional group which causes a polymerization reaction at the end of the molecule by the energy of heat or light, of which the number of repeating structural units of the molecule is 2 ~
Relatively large molecules of about 20 are oligomers, and those of less than 20 are monomers. Examples of the functional group that causes the polymerization reaction include an acryloyl group, a methacryloyl group, a vinyl group,
A group having a carbon-carbon double bond such as an acetophenone group,
Examples thereof include those that cause ring-opening polymerization of a silanol group, a cyclic ether group and the like, and those that cause polymerization by reacting two or more kinds of molecules such as phenol + formaldehyde. In the present invention, a curable phenol resin is particularly preferable. Phenolic resin is a resin generally obtained by the reaction of phenols and formaldehyde. There are two types of phenolic resin, a resol type obtained by adding formaldehyde to phenols in excess and reacting with an alkali catalyst, and a novolac obtained by adding phenols to formaldehyde in excess and reacting with an acid catalyst. Divided into types.

The resol type is also soluble in alcohols and ketones and is heated to form a cured product by three-dimensionally crosslinking and polymerizing. On the other hand, the novolac type generally does not cure when heated as it is, but a cured product is produced by adding a formaldehyde source such as paraformaldehyde or hexamethylenetetramine and heating.

Generally, industrially, resole is used as a varnish for paints, adhesives, cast products and laminated products, and novolac is mainly used as a molding material and a binder.

The phenolic resin used as the binder resin in the present invention can be either of the above-mentioned resol type and novolak type, but it is cured without adding a curing agent, and it is easy to use as a paint. It is preferable to use a resol type.

Usually, the resol type phenol resin is produced by subjecting a phenol compound and an aldehyde compound to an alkali catalyst. The main phenols used include, but are not limited to, phenol, cresol, xylenol, paraalkylphenol, paraphenylphenol, resorcin and bisphenol. The aldehydes include, but are not limited to, formaldehyde, paraformaldehyde, furfural, acetaldehyde and the like.

Monomers of phenols, dimethylolphenols and trimethylolphenols, and their mixtures, or those obtained by oligomerizing them, by reacting these phenols with aldehydes under an alkaline catalyst, and Make a mixture of monomers and oligomers. Among them, a relatively large molecule having repeating structural units of 2 to 20 is an oligomer, and one is a monomer. Examples of the alkali catalyst used include metal-based alkali compounds and amine compounds, and examples of the metal-based alkali compound include NaOH and K.
Hydroxides of alkali metals and alkaline earth metals such as OH and Ca (OH) ₂ may be used as amine compounds such as ammonia, hexamethylenetetramine, trimethylamine,
Examples thereof include, but are not limited to, triethylamine and triethanolamine. In the present invention, it is preferable to use ammonia and an amine compound in consideration of the fluctuation of resistance under a high humidity environment, and it is more preferable to use an amine compound in consideration of the stability of the solution. In the present invention, these phenolic resins may be used alone or in combination of two or more,
It is also possible to use a mixture of a resole type and a novolak type.

When the protective layer in the present invention is a thermosetting type, after the protective layer is coated on the photosensitive layer, it is usually cured in a hot air drying oven or the like. The curing temperature at this time is 100 ° C.
To 300 ° C is preferable, and 120 ° C to 200 ° C is particularly preferable.

In the present invention, "the resin is cured" means that the resin is not dissolved in an alcohol solvent such as methanol or ethanol. The film thickness of the charge injection layer is preferably 0.5 μm to 10 μm, and particularly preferably 1 μm to 7 μm.

The mixing ratio of the charge transport material and the curable resin in the protective layer of the present invention is a mass transport ratio of charge transport material / curable resin = 0.1 / 10 to 20/10, and more preferably,
It is 0.5 / 10 to 10/10.

Next, the photosensitive layer will be described.

The photoreceptor of the present invention has a laminated structure. Figure 4
In the electrophotographic photosensitive member a, the charge generation layer 3 and the charge transport layer 2 are sequentially provided on the conductive support 4, and the protective layer 1 is further provided on the outermost surface.

Further, as shown in b and c of FIG.
A binding layer 5 and an undercoat layer 6 for the purpose of preventing interference fringes may be provided between the charge generation layer 3 and the charge generation layer 3.

As the conductive support 4, a support itself having conductivity such as aluminum, aluminum alloy, stainless steel, etc. may be used. In addition, aluminum, aluminum alloy, indium oxide-tin oxide alloy, etc. are vacuum-deposited. According to the above-mentioned conductive support having a film forming layer, plastic, conductive fine particles (for example, carbon black, tin oxide, titanium oxide, silver particles, etc.) impregnated in plastic or paper together with an appropriate binder resin, conductive A plastic having a binder resin or the like can be used.

A binding layer (adhesive layer) having a barrier function and an adhesive function can be provided between the conductive support and the photosensitive layer. The binder layer is for improving the adhesiveness of the photosensitive layer, improving the coating property, protecting the support, covering the defects of the support, improving the charge injection property from the support, protecting the photosensitive layer against electrical breakdown, etc. It is formed. The binder layer can be formed of casein, polyvinyl alcohol, ethyl cellulose, ethylene-acrylic acid copolymer, polyamide, modified polyamide, polyurethane, gelatin, aluminum oxide or the like. The thickness of the binder layer is preferably 5 μm or less, and 0.2 to 3
μm is more preferred.

Examples of the charge generating material used in the present invention include phthalocyanine pigments, azo pigments, indigo pigments, polycyclic quinone pigments, perylene pigments, quinacridone pigments, azurenium salt pigments, pyrylium dyes, thiopyrylium dyes, squarylium dyes, cyanines. Examples thereof include dyes, xanthene dyes, quinoneimine dyes, triphenylmethane dyes, styryl dyes, selenium, selenium-tellurium, amorphous silicon, cadmium sulfide, and zinc oxide.

The charge generating layer is formed by coating a liquid obtained by dissolving or dispersing the above charge generating material in a binder resin solution obtained by dissolving it in a solvent on a conductive support. As such a resin solution-forming solvent, for example, an organic solvent such as alcohols, sulfoxides, ketones, ethers, esters, aliphatic halogenated hydrocarbons or aromatic compounds is used. It is selected from the solubility and dispersibility of the resin and the charge generation material.

The coating solution for forming the charge generating layer comprises a homogenizer, an ultrasonic wave, a ball mill, a sand mill, an attritor, and a roll mill, together with the above-mentioned charge generating material, a binder resin in an amount of 0.3 to 4 times that of the charge generating material, and a solvent. And the like, are uniformly dispersed, coated on a support and dried to be formed. The thickness is preferably 5 μm or less, more preferably 0.01 to 1
It is in the μm range.

Typical examples of the charge transport material include hydrazone compounds, pyrazoline compounds, styryl compounds, oxazole compounds, thiazole compounds, triarylmethane compounds, polyarylalkane compounds and the like.

The charge transport layer is generally formed by dissolving the above charge transport material and the binder resin in a solvent and applying the solution.
The mixing ratio of the charge transport material and the binder resin is a mass ratio,
It is about 2: 1 to 1: 2. Examples of the solvent include ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, chlorobenzene and chloroform,
Chlorine hydrocarbons such as carbon tetrachloride are used. When applying this solution, for example, dip coating method,
A coating method such as a spray coating method or a spinner coating method can be used, and the drying is performed at 10 ° C to
It can be carried out at a temperature in the range of 200 ° C., preferably 20 ° C. to 150 ° C. for 5 minutes to 5 hours, preferably 10 minutes to 2 hours under blast drying or static drying.

The binder resin used to form the charge transport layer includes acrylic resin, styrene resin, polyester, polycarbonate resin, polyarylate, polysulfone, polyphenylene oxide, epoxy resin, polyurethane resin, alkyd resin, and A resin selected from saturated resins and the like is preferable. As a particularly preferred resin,
Polymethylmethacrylate, polystyrene, styrene-
An acrylonitrile copolymer, a polycarbonate resin or a diallyl phthalate resin may be used. The thickness of the charge transport layer is preferably 5 to 40 μm, more preferably 10
˜30 μm.

Further, the charge generation layer or the charge transport layer may contain various additives such as an antioxidant, an ultraviolet absorber and a lubricant. Furthermore, on the photosensitive layer,
The protective layer is applied and cured to form a film.

Further, the protective layer can be applied and cured to form a film on a photosensitive layer containing both a charge generating material and a charge transporting material, that is, a so-called single-layer photosensitive layer.

FIG. 5 shows a specific example of an electrophotographic apparatus using the electrophotographic photosensitive member of the present invention. This apparatus comprises a primary belt means 1 on the peripheral surface of an electrophotographic photosensitive member (hereinafter referred to as a photosensitive member) 11.
3, an image exposure unit 14, a developing unit 15, and a transfer unit 16 are arranged.

In the image forming method, first, a voltage is applied to the primary charging means 13 arranged in contact with the photosensitive member 11,
The surface of the photoconductor 11 is charged, and an image corresponding to a document is exposed on the surface of the photoconductor 11 by the image exposure means 14 to form an electrostatic latent image. Next, the toner in the developing means 15 is removed from the photosensitive member 11.
The electrostatic latent image on the photoconductor 11 is developed (visualized) by being attached to. Further, the transfer means 1 is transferred onto the transfer material 17 such as paper to which the toner image formed on the photoconductor 11 is supplied.
The residual toner remaining on the photoconductor 11 without being transferred to the transfer material is collected by a cleaner or the like. In recent years, cleanerless systems have also been studied, and residual toner can be collected by a developing device or the like.

In the present invention, the above-mentioned photoconductor 11, primary charging means 13, developing means 15 and cleaning means 1 are used.
Of the 9 and other components, a plurality of components are housed in a container and integrally combined as a process cartridge, and the process cartridge is configured to be detachable from the main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. You may. For example, at least one of the primary charging unit 13, the developing unit 15, and the cleaning unit 19 is integrally supported with the photoconductor 11 to form a cartridge, and the cartridge is detachably attached to the apparatus main body by using a guide unit such as a rail of the apparatus main body. It can be a cartridge.

In this image forming apparatus, the image exposure means 1
As the light source of 4, a halogen light, a fluorescent lamp, a laser light, an LED, or the like can be used. Also, other auxiliary processes may be added if necessary.

The electrophotographic photosensitive member of the present invention can be used not only in an electrophotographic copying machine but also in a laser beam printer,
It can be widely used in electrophotographic application fields such as CRT printers, LED printers, liquid crystal printers, and laser plate making.

[0061]

EXAMPLES The present invention will be described in more detail with reference to specific examples. In addition, "part" and "%" in the examples
Indicates parts by mass and% by mass.

(Example 1) 30 mmφ × 260.5 mm
The aluminum cylinder as a support was used as a support, and a 5% by mass methanol solution of a polyamide resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) was applied onto the aluminum cylinder by a dipping method to form an undercoat layer having a thickness of 0.5 μm. It is provided. Next, the Bragg angle (2
θ ± 0.2 °) 9.0, 14.2, 23.9 and 27.1
Where it has a strong peak at

[0063]

[Chemical 13] 4 parts of titanyl oxophthalocyanine pigment (parts by mass, the same applies hereinafter), polyvinyl butyral resin (trade name: BX-
2 parts of Sekisui Chemical Co., Ltd., and 80 parts of cyclohexanone were dispersed for about 4 hours with a sand mill containing 1 mmφ glass beads to prepare a dispersion liquid for the charge generation layer. This was applied by a dipping method to form a charge generation layer having a film thickness of 0.3 μm.

Then, the following structural formula

[0065]

[Chemical 14] Compound of 10 parts and bisphenol Z type polycarbonate (trade name: Z-200, manufactured by Mitsubishi Gas Chemical Co., Inc.)
10 parts were dissolved in 100 parts monochlorobenzene. This solution was applied onto the charge generation layer and dried in hot air at 105 ° C. for 1 hour to form a 17 μm charge transport layer.

Next, as a protective layer, polytetrafluoroethylene fine particles (average particle size 0.1
20 parts of 8 μm) were added and dispersed by a sand mill. Then, 70 parts of the charge transport material represented by the following structural formula was dissolved.

[0067]

[Chemical 15] Further, as a curable resin, 100 parts of a thermosetting resol type phenol resin (trade name: PL-4852, using an amine compound catalyst, manufactured by Gunei Chemical Industry Co., Ltd.) was dissolved to prepare a preparation liquid.

Using this prepared solution, a film was formed on the above charge transport layer by a dip coating method, and the film was formed at a temperature of 145 ° C.
It was dried with hot air for a period of time to obtain a protective layer. At this time, the thickness of the obtained protective layer was 2 μm. Further, the dispersibility of the protective layer preparation liquid was good, and the film surface was a uniform and even surface.

First, Hewlett-Packard Co., Ltd. is used so that the voltage can be applied to the primary charging roller by an external power source.
The Laserjet 4000 manufactured was modified. With this device, only the DC voltage is applied, and the dark potential of the photoconductor is -600.
The evaluation was performed by setting so as to be (V). At this time,
The voltage applied to the charging member was -1180 (V). Using this electrophotographic apparatus, a halftone image (1 dot 2 spaces) was evaluated in an environment of 23 ° C./50% RH. Further, in a 15 ° C./10% RH environment, evaluation was performed on the initial halftone image and the halftone image after the endurance of 5,000 sheets.

Further, the hardness value Hplas of plastic deformation on the protective layer
The value of t is the hardness tester (H1 manufactured by Germany FISCHER Co., Ltd.).
00VP-HCU) under the environment of 22 ° C / 52% RH under the above-mentioned conditions.

Further, the electrostatic capacity C of the photoconductor is measured by cutting the electrophotographic photoconductor into a certain size (1.5c).
m × 1.5 cm), a certain size (1
cm × 1 cm) to form an electrode by vapor deposition of gold.
A conductive support was used as the counter electrode, and this was used as a sample using an impedance measuring device (YHP-4192A, manufactured by Yokogawa Hewlett-Packard Co., Ltd.). If the sample has a large curvature and cannot be installed in the measuring device, it is necessary to modify the sample holder slightly. Further, the sample does not depend on the size, and if the size of the electrode can be accurately measured, it can be converted into the capacitance per 1 cm ² , so that there is no problem with any size.

The results are shown in Table 1.

(Examples 2 to 7) In Example 1, the thickness of the charge transport layer was 13 μm, 11 μm, 8 μm, 5 μm.
The procedure was exactly the same as in Example 1 except that the thickness was 3 μm and 2 μm, and the voltage applied to the charging member was changed so that the photoconductor dark potential was −600 (V). At this time, the applied voltages applied to the charging member are -1150 (V) and -1130, respectively.
(V), -1100 (V), -1070 (V), -10
It was 40 (V) and -1030 (V).

Comparative Examples 1 to 3 The procedure of Example 1 was repeated except that the thickness of the charge transport layer was changed to 21 μm, 23 μm and 30 μm. At this time, in order to set the dark potential of the photoconductor to -600 (V), the voltage applied to the charging member is -1210 (V), -1230 (V),
It was -1280 (V).

(Example 8) In Example 3, the resol type phenol resin was replaced with methylphenyl polysiloxane (K
F-50500CS: manufactured by Shin-Etsu Silicone Co., Ltd., except that the procedure was the same as in Example 3.

Example 9 In Example 3, 50 parts of xylene as a solvent was added, the resole-type phenol resin was changed to acrylic polyol (GR4026, Kansai Paint Co., Ltd.), and hexamethylene diisocyanate was used as a curing agent. Example 3 was repeated except that 5 parts of was added.

(Comparative Example 4) The procedure of Example 8 was repeated, except that the amount of methylphenylpolysiloxane added was changed to 50 parts.

Comparative Example 5 The procedure of Example 9 was repeated, except that the amount of acrylic polyol added was changed to 170 parts and the amount of hexamethylene diisocyanate was changed to 7 parts.

(Examples 10 and 11) In Example 8,
Except that the thickness of the protective layer was changed to 4 μm and 6 μm,
Completely the same as in Example 8. At that time, in order to set the dark potential of the photoconductor to -600 (V), the voltage applied to the charging member was set to -1150 (V) and -1170 (V).

(Comparative Example 6) The procedure of Example 8 was repeated except that the thickness of the protective layer was changed to 0.5 μm. At that time, set the dark potential of the photoconductor to -600 (V).
In order to make the
(V).

Comparative Example 7 The same procedure as in Example 9 was carried out except that the thickness of the protective layer was changed to 8 μm. At that time, in order to set the dark potential of the photoconductor to -600 (V), the voltage applied to the charging member was set to -1170 (V).

(Examples 12 to 14) In Example 1,
As for the voltage to be applied to the charging member for the primary charging, the alternating voltage is superimposed on the direct current voltage -600 (V) from the application of only the direct current voltage, and the peak-to-peak voltage Vpp of the alternating voltage.
(V) is 1150 (V) (2 × Vth = 2 × 572 = 1
144 (V)) 1440 (V) and 1540
Except for setting to (V), the same operation as in Example 1 was performed.

(Comparative Examples 8 and 9) In Examples 12 to 14, the peak-to-peak voltage Vpp (V) of the alternating voltage was obtained.
Was carried out in exactly the same manner as in Examples 12 to 14 except that the temperature was set to 1100 (V) and 1600 (V).

(Examples 15 to 17) In Example 2,
As for the voltage to be applied to the charging member for the primary charging, the alternating voltage is superimposed on the direct current voltage -600 (V) from the application of only the direct current voltage, and the peak-to-peak voltage Vpp of the alternating voltage.
(V) to 1100 (V) (2 × Vth = 2 × 540 = 1
080 (V)) 1350 (V) and 1450
Except for setting to (V), the same operation as in Example 2 was performed.

(Comparative Examples 10 and 11) In Examples 15 to 17, the peak-to-peak voltage Vpp of the alternating voltage was obtained.
Except for changing (V) to 1000 (V) and 1500 (V), the same operation as in Examples 15 to 17 was performed.

(Examples 18 to 20) In Example 4,
As for the voltage to be applied to the charging member for the primary charging, the alternating voltage is superimposed on the direct current voltage -600 (V) from the application of only the direct current voltage, and the peak-to-peak voltage Vpp of the alternating voltage.
(V) is 1000 (V) (2 × Vth = 2 × 493 = 9
86 (V)), 1250 (V), and 1350
Except for setting to (V), the same operation as in Example 4 was performed.

(Comparative Examples 12 and 13) In Examples 18 to 20, the peak-to-peak voltage Vpp of the alternating voltage was obtained.
Except for changing (V) to 950 (V) and 1450 (V), the same procedure as in Examples 18 to 20 was performed.

Comparative Examples 14 and 15 In Examples 12 to 14, the thickness of the charge transport layer was set to 21 μm, and the peak-to-peak voltage Vpp (V) of the alternating voltage of the voltage applied to the primary charging member was set. 1250 (V) (2 × Vth =
2 × 605 = 1210 (V)) and 1450
Except for setting to (V), the same procedure as in Examples 12 to 14 was performed.

(Comparative Examples 16 and 17) In Examples 12 to 14, the thickness of the charge transport layer was 23 μm, and the peak-to-peak voltage Vpp (V) of the alternating voltage of the voltage applied to the primary charging member. 1300 (V) (2 × Vth =
2 × 620 = 1240 (V)), and 1500
Except for setting to (V), the same procedure as in Examples 12 to 14 was performed.

(Embodiment 21) In Embodiment 8, the voltage applied to the charging member for primary charging is changed from the application of only the DC voltage to the DC voltage −600 (V) by superimposing the alternating voltage, and the peak of the alternating voltage.・ Two peak voltage Vpp (V) is 1
300 (V) (2 × Vth = 2 × 575 = 1150
Except for setting to (V)), the same operation as in Example 8 was performed.

(Comparative Example 18) In Example 21, the addition amount of methylphenylpolysiloxane used in the protective layer was changed to 5
The same procedure as in Example 21 was repeated except that the content was changed to 0 part.

(Embodiment 22) In Embodiment 9, the voltage applied to the charging member for the primary charging is changed from the application of only the DC voltage to the DC voltage of -600 (V) and the alternating voltage is superimposed, and the peak of the alternating voltage is obtained.・ Two peak voltage Vpp (V) is 1
300 (V) (2 × Vth = 2 × 575 = 1150
Except for setting to (V)), the same operation as in Example 9 was performed.

Comparative Example 19 Example 2 was repeated except that the amount of acrylic polyol added was changed to 170 parts and hexamethylene diisocyanate was changed to 7 parts.
Completely the same as 2.

(Comparative Example 20) The same operation as in Example 21 was carried out except that the thickness of the protective layer was changed to 0.5 μm.

(Comparative Example 21) The same operation as in Example 22 was carried out except that the thickness of the protective layer was changed to 8 μm.

(Examples 23 and 24) Examples 23 to 24 were carried out in the same manner as Examples 12 to 14 except that the charge transporting material used for the protective layer was changed to the following compound.

[0097]

[Chemical 16] (Examples 25 to 30) In Examples 23 and 24, the thickness of the charge transport layer was 13 μm, 11 μm, 8 μm, 5 μm, 3 μm.
m to 2 μm, and the peak-to-peak voltage Vpp (V) of the alternating voltage of the voltage applied to the primary charging member
1100 (V) (each greater than 2 × Vth,
Except for setting to 2 × Vth + 400 (V)), the same operation as in Examples 23 and 24 was performed.

(Comparative Examples 22 and 23) In Examples 23 and 24, the thickness of the charge transport layer was changed to 21 μm and 23 μm, and the peak-to-peak alternating voltage of the voltage applied to the primary charging member was changed. Voltage Vpp (V) is 1450
(V) (each greater than 2 × Vth, 2 × Vth
Except for setting it to +400 (V), the same procedure as in Examples 23 and 24 was performed.

[0099]

[Table 1]

[0100]

[Table 2]

[0101]

[Table 3]

[0102]

As shown in Tables 1 to 3, according to the present invention, excellent durability against abrasion, stable primary charging, fusion, scratches, cleaning blade, etc. It was possible to provide an electrophotographic photosensitive member capable of maintaining a high-quality image without any abnormal noise caused by rubbing, and an electrophotographic apparatus and a process cartridge having the electrophotographic photosensitive member.

[0103]

[Brief description of drawings]

FIG. 1 is a diagram showing an example of hardness values as a result of measurement by a Fischer hardness meter.

FIG. 2 is a diagram showing a difference between discharge charging and injection charging when only a DC voltage is applied as a voltage for primary charging.

FIG. 3 is a diagram showing a difference between discharge charging and injection charging when an alternating voltage is superimposed on a DC voltage as an applied voltage of primary charging.

FIG. 4 is a diagram showing a layer structure of a photoconductor.

FIG. 5 is a diagram showing a specific example of an electrophotographic apparatus.

[Explanation of symbols]

1: Surface protection layer 2: Charge transport layer 3: Charge generation layer 4: Conductive support 5: Tie layer 6: Undercoat layer 11: Electrophotographic photoreceptor 12: Photoconductor rotating shaft 13: Primary charging means 14: Image exposure means 15: developing means 16: Transfer means 17: Transfer material 18: Fixing means 19: Cleaning means 20: Pre-exposure means 21: Cartridge frame 22: Guide rail

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/02 101 G03G 15/02 101 102 102 (72) Inventor Kimihiro Yoshimura 3-30 Shimomaruko, Ota-ku, Tokyo No. 2 In Canon Inc. (72) Inventor Tatsuya Ikezue 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Daisuke Tanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Non-Co., Ltd. F term (reference) 2H068 AA03 AA05 AA06 AA08 AA28 BA12 BB31 BB33 BB35 BB58 CA05 CA33 FA01 FA15 FA19 FA27 FC01 2H200 FA16 GA17 GA28 HA03 HA28 HB12 HB23 HB45 HB46 HB48 MA04 MB01 NA02 NA06 NA09

Claims (31)

[Claims] 1. An electrophotographic photosensitive member and a charging member disposed in contact with the photosensitive member, and by applying only a DC voltage from the charging member to the photosensitive member, the surface of the photosensitive member is discharged. DC charging voltage Vdc (V) when charging,
Dark potential Vd (V) of the photoconductor and discharge start voltage Vth
The relationship of (V) is expressed by the following expression (1) | Vdc |-| Vd |> | Vth | / 2 (1) In an electrophotographic photosensitive member used in an electrophotographic apparatus that satisfies D = L (film thickness of photosensitive member μm) / K (relative permittivity of photosensitive layer), the photosensitive member includes at least a photosensitive layer on a conductive support, A surface protective layer is sequentially formed, and the hardness value Hplast (N / mm ² ) of plastic deformation of the surface protective layer satisfies the following formula (2): 300 N / mm ² ≤ Hplast ≤ 600 N / mm ² (2) And an electrostatic capacity C (pF / cm ² ) per 1 cm ² of the photoconductor satisfies the following formula (3): electrostatic capacity C ≧ 140 pF / cm ² (3). Photoconductor. 2. An electrophotographic photosensitive member and a charging member disposed in contact with the photosensitive member, and by applying a voltage obtained by superimposing an alternating voltage on a DC voltage from the charging member to the photosensitive member. When the surface of the photoconductor is charged by discharge, the peak-to-peak voltage Vpp (V) of the alternating voltage is expressed by the following formula (4) 2 × Vth ≦ Vpp ≦ 2 × Vth + 400 (V) (4) An electrophotographic photosensitive member used in an electrophotographic apparatus satisfying D = L (photosensitive member film thickness μm) / K (relative permittivity of photosensitive layer), wherein the photosensitive member is at least a photosensitive layer on a conductive support, and ,
Surface protection layers are sequentially formed, and the hardness value Hplast (N / mm ² ) of plastic deformation on the surface protection layer is expressed by the following formula (2) 300 N / mm ² ≤ Hplast ≤ 600 N / mm ² (2) Electrons which are satisfied and whose capacitance C (pF / cm ² ) per 1 cm ² of the photoconductor satisfies the following formula (3): capacitance C ≧ 140 pF / cm ² (3) Photoreceptor. 3. The electrophotographic photosensitive member according to claim 2, wherein the peak-to-peak voltage Vpp (V) of the alternating voltage satisfies the following expression (5). 2 × Vth ≦ Vpp ≦ 2 × Vth + 300 (V) (5) 4. The electrostatic capacity C (pF / cm ² ) per 1 cm ^{2 of the} electrophotographic photosensitive member satisfies the following formula (6): electrostatic capacity C ≧ 170 pF / cm ² (6). The electrophotographic photosensitive member according to item 3. 5. The electrostatic capacity C (pF / cm ² ) per 1 cm ^{2 of the} electrophotographic photosensitive member satisfies the following formula (7): electrostatic capacity C ≧ 200 pF / cm ² (7). The electrophotographic photosensitive member according to item 3. 6. The capacitance C (pF / cm ² ) per 1 cm ^{2 of the} electrophotographic photosensitive member satisfies the following formula (8): capacitance C ≦ 500 pF / cm ² (8). 5. The electrophotographic photosensitive member according to any one of 5 above. 7. The electrophotographic photosensitive member according to claim 1, wherein the surface protective layer contains a resin and contains at least one of a charge transport material and conductive particles. . 8. The electrophotographic photoreceptor according to claim 7, wherein the charge transport material in the surface protective layer contains at least one substituent selected from the group consisting of hydroxyalkyl groups and hydroxyalkoxy groups. 9. The electrophotographic photoreceptor according to claim 7, wherein the charge transport material in the surface protective layer contains at least one phenolic residue. 10. A charge transport material having at least one substituent selected from the group consisting of a hydroxyalkyl group and a hydroxyalkoxy group, having the following structural formula (1):
~ (3) [Chemical formula 1] (In the formula, R ₁ , R ₂ , and R ₃ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and A, B, and D each represent a halogen atom or a substituent as a substituent. An alkyl group which may have, an alkoxy group which may have a substituent,
Represents an aryl group which may have a substituent, a benzene ring which may have one or more heterocyclic groups which may have a substituent,
a, b, d, m and n are 0 or 1. ) [Chemical 2] (In the formula, R ₄ , R ₅ , and R ₆ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and E and F each have a halogen atom or a substituent as a substituent. Optionally substituted alkyl group, optionally substituted alkoxy group, optionally substituted aryl group, optionally substituted heterocyclic group benzene ring , E,
f and g are 0 or 1, p, q, and r are 0 or 1, and not all become 0 at the same time. Z ₁ and Z ₂ may have a halogen atom or a substituent, respectively. An alkyl group, an alkoxy group which may have a substituent, an aryl group which may have a substituent, and a heterocyclic group which may have a substituent are shown, and they may jointly form a ring. ) [Chemical 3] (In the formula, R ₆ , R ₇ , R ₈ and R ₉ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and G, J,
K and L each have a halogen atom as a substituent, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an aryl group which may have a substituent, and a substituent. Represents a benzene ring which may have one or more heterocyclic groups, g, h, j, k, q, r and s are 0 or 1, and Z ₃ and Z ₄ are each a halogen atom or a substituent. An alkyl group which may have a group, an alkoxy group which may have a substituent, an aryl group which may have a substituent and a heterocyclic group which may have a substituent, and jointly form a ring. May be done. The electrophotographic photosensitive member according to claim 8, which is represented by any one of (1) to (9). 11. The phenolic residue is at least 1
The charge transporting material possessed by one of the following structural formulas (4) to (6): (In the formula, R ₁ represents a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and R ₂ represents a hydrogen atom, an alkyl group which may have a substituent, or a substituent. Represents an optionally substituted aralkyl group or an optionally substituted phenyl group, and Ar ₁ and Ar ₂ each have an optionally substituted alkyl group, an optionally substituted aralkyl group, or an optionally substituted group. Optionally represents an aryl group or a heterocyclic group which may have a substituent, Ar ₃
Represents an arylene group which may have a divalent substituent, a heterocyclic group which may have a divalent substituent, m and n are each 0 or 1, and when n = 0, m = 0 and A
And D each have a halogen atom as a substituent, an alkyl group that may have a substituent, an alkoxy group that may have a substituent, an aryl group that may have a substituent, or a substituent. It represents a benzene ring which may have one or more good heterocyclic groups. ) [Chemical 5] (In the formula, R ₃ represents a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and Ar ₄ and Ar ₅ each have an alkyl group which may have a substituent or a substituent which may have a substituent. Represents an aralkyl group which may have a substituent, an aryl group which may have a substituent, or a heterocyclic group which may have a substituent, and E and G each represent a halogen atom as a substituent or an alkyl which may have a substituent. Group, an alkoxy group which may have a substituent, an aryl group which may have a substituent, a benzene ring which may have one or more heterocyclic groups which may have a substituent, E And G may jointly form a ring via a substituent, and p is 0 or 1.) (In the formula, R ₄ and R ₅ each represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched, and Ar ₆ has an alkyl group which may have a substituent or a substituent which may have a substituent. Optionally represents an aralkyl group, an aryl group which may have a substituent, and a heterocyclic group which may have a substituent, and J, K, L, and M each represent a halogen atom or a substituent as a substituent. It may have one or more alkyl groups that may have, alkoxy groups that may have a substituent, aryl groups that may have a substituent, and heterocyclic groups that may have a substituent. Represents a benzene ring, J and K, and L and M may jointly form a ring via a substituent, and q and r are each 0 or 1). The electrophotographic photosensitive member according to claim 9. 12. The electrophotographic photosensitive member according to claim 7, wherein the resin is a curable resin. 13. The electrophotographic photosensitive member according to claim 12, wherein the curable resin is a phenol resin. 14. The electrophotographic photosensitive member according to claim 13, wherein the phenol resin is a resol-type phenol resin. 15. The electrophotographic photosensitive member according to claim 14, wherein the resol-type phenol resin is a resin synthesized by using an amine compound. 16. The electrophotographic photosensitive member according to claim 14, wherein the resol-type phenol resin is a resin synthesized by using an amine compound except ammonia. 17. The electrophotographic photosensitive member according to claim 7, wherein the curable resin is a thermosetting resin that is cured by heat. 18. The electrophotographic photosensitive member according to claim 1, wherein the surface protective layer contains lubricating particles. 19. The electrophotographic photosensitive member according to claim 18, wherein the lubricating particles are at least one selected from the group consisting of fluorine atom-containing resin particles, silicone particles, silicon particles and alumina particles. 20. An electrophotographic photosensitive member and a charging member disposed in contact with the photosensitive member, and the surface of the photosensitive member is charged by discharging by applying only direct current to the photosensitive member from the charging member. When applied, the DC applied voltage Vdc (V), the dark potential Vd (V) of the photoconductor, and the discharge start voltage Vth
The relationship of (V) is expressed by the following formula (1) | Vdc |-| Vd |> | Vth | / 2 (1) In a process cartridge for an electrophotographic apparatus satisfying D = L (film thickness μm of photoconductor) / K (relative permittivity of photoconductive layer), the photoconductor is a photoconductive layer at least on a conductive support, and a surface protective layer. And the hardness value Hplast of plastic deformation on the surface protective layer (N / mm ² ) satisfies the following formula (2) 300 N / mm ² ≤ Hplast ≤ 600 N / mm ² (2), The process cartridge, wherein the electrostatic capacity C (pF / cm ² ) per 1 cm ² of the photoconductor satisfies the following formula (3): electrostatic capacity C ≧ 140 pF / cm ² (3). 21. An electrophotographic photosensitive member and a charging member disposed in contact with the photosensitive member, and the surface of the photosensitive member is charged by discharging by applying only direct current from the charging member to the photosensitive member. When applied, the DC applied voltage Vdc (V), the dark potential Vd (V) of the photoconductor, and the discharge start voltage Vth
The relationship of (V) is expressed by the following equation (1) | Vdc |-| Vd |> | Vth | / 2 (1) In an electrophotographic apparatus satisfying D = L (photosensitive member film thickness μm) / K (photosensitive layer relative dielectric constant), the photosensitive member sequentially forms a photosensitive layer and a surface protective layer on at least a conductive support. The value (N / mm ² ) of the plastic deformation hardness value Hplast on the surface protective layer satisfies the following formula (2): 300 N / mm ² ≤ Hplast ≤ 600 N / mm ² (2), and An electrophotographic apparatus, wherein the electrostatic capacity C (pF / cm ² ) per 1 cm ^{2 of the} photoconductor satisfies the following formula (3): electrostatic capacity C ≧ 140 pF / cm ² (3). 22. An electrophotographic photosensitive member and a charging member disposed in contact with the photosensitive member, and by applying a voltage obtained by superposing an alternating voltage to a DC voltage from the charging member to the photosensitive member, When the surface of the photoconductor is charged by discharge, the peak-to-peak voltage Vpp (V) of the alternating voltage is expressed by the following formula (4) 2 × Vth ≦ Vpp ≦ 2 × Vth + 400 (V) (4) D = L (photoconductor film thickness μm) / K (photosensitive layer dielectric constant)
In the process cartridge for an electrophotographic apparatus, the photosensitive member has a photosensitive layer and a surface protective layer sequentially formed on at least a conductive support, and a value of hardness value Hplast of plastic deformation on the surface protective layer. (N / mm ² ) satisfies the following formula (2) 300 N / mm ² ≤ Hplast ≤ 600 N / mm ² (2), and the electrostatic capacitance C (pF / cm ² ) per 1 cm ² of the photoconductor is Satisfies the following formula (3): electrostatic capacitance C ≧ 140 pF / cm ² (3). 23. An electrophotographic photosensitive member and a charging member disposed in contact with the photosensitive member, wherein a voltage obtained by applying an alternating voltage to a DC voltage is applied from the charging member to the photosensitive member. When the surface of the photoconductor is charged by discharge, the peak-to-peak voltage Vpp (V) of the alternating voltage is expressed by the following equation (4) 2 × Vth ≦ Vpp ≦ 2 × Vth + 400 (V) (4) In an electrophotographic apparatus satisfying D = L (film thickness μm of photosensitive member) / K (relative permittivity of photosensitive layer), the photosensitive member is at least a photosensitive layer on a conductive support, and
A surface protective layer is sequentially formed, and the value (N / mm ² ) of the hardness value Hplast of plastic deformation on the surface protective layer is given by the following formula (2): 300 N / mm ² ≤ Hplast ≤ 600 N / mm ² (2) Electrons which are satisfied and whose capacitance C (pF / cm ² ) per 1 cm ² of the photoconductor satisfies the following formula (3): capacitance C ≧ 140 pF / cm ² (3) Photographic equipment. 24. The peak-to-peak voltage Vpp (V) of the alternating voltage satisfies the following expression (5).
The process cartridge described in 1. 2 × Vth ≦ Vpp ≦ 2 × Vth + 300 (V) (5) 25. The peak-to-peak voltage Vpp (V) of the alternating voltage satisfies the following expression (5).
The electrophotographic apparatus according to 1. 2 × Vth ≦ Vpp ≦ 2 × Vth + 300 (V) (5) 26. The electrostatic capacitance C (p
The process cartridge according to claim 20, 22 or 24, wherein F / cm ² ) satisfies the following formula (6): capacitance C ≧ 170 pF / cm ² (6). 27. The electrostatic capacitance C (p
The electrophotographic apparatus according to claim 21, 23 or 25, wherein F / cm ² ) satisfies the following formula (6): capacitance C ≧ 170 pF / cm ² (6). 28. The electrostatic capacitance C (p
The process cartridge according to claim 20, 22 or 24, wherein F / cm ² ) satisfies the following formula (7): capacitance C ≧ 200 pF / cm ² (7). 29. The electrostatic capacitance C (p
The electrophotographic apparatus according to claim 21, 23 or 25, wherein F / cm ² ) satisfies the following formula (7): capacitance C ≧ 200 pF / cm ² (7). 30. The electrostatic capacitance C (p
The process cartridge according to any one of claims 20, 22, 24, 26 and 28, wherein F / cm ² ) satisfies the following formula (8): capacitance C ≤ 500 pF / cm ² (8). 31. The electrostatic capacitance C (p of the electrophotographic photosensitive member
The electrophotographic apparatus according to any one of claims 21, 23, 25, 27 and 29, wherein F / cm ² ) satisfies the following formula (8): capacitance C ≤ 500 pF / cm ² (8).