JP2003248330A - Electrophotographic photosensitive member, process cartridge and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photosensitive member having a protective layer whose scratch resistance and wear resistance are improved, and which is prevented from peeling off and melt-sticking even in the case a photosensitive layer and the protective layer are formed on a small-diameter cylindrical support, and also, wherein the occurrence of noise such as a creak is prevented, and to provide a process cartridge and an electrophotographic apparatus equipped with the electrophotographic photosensitive member. <P>SOLUTION: As for the electrophotographic photosensitive member constituted by forming a the photosensitive layer and the protecting layer on the cylindrical support whose outer diameter is <30 mm in this order, the difference |α<SB>1</SB>-α<SB>2</SB>| between a thermal expansion coefficient (α<SB>1</SB>) measured from the top of the protecting layer and the thermal expansion coefficient (α<SB>2</SB>) measured after removing the protecting layer is >5.0×10<SP>-7</SP>[°C<SP>-1</SP>] and <1.0×10<SP>-4</SP>[°C<SP>-1</SP>], and the modulus of elastic deformation (We%) measured from the top of the protecting layer is >30[%] and <60[%]. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrophotographic photoreceptor,
More specifically, the present invention relates to a process cartridge having an electrophotographic photosensitive member and an electrophotographic apparatus, in which a photosensitive layer and a protective layer are provided in this order on a cylindrical support, and the outer diameter of the cylindrical support is 3
The present invention relates to an electrophotographic photosensitive member having a size of less than 0 mm, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus.

[0002]

2. Description of the Related Art With the recent trend toward higher image quality, higher speed and higher durability, organic electrophotographic photoreceptors using organic photoconductive materials are required to have further improved mechanical durability.

Further, in recent years, electrophotographic apparatuses such as printers, copiers and facsimiles using electrophotographic photosensitive members have come to be used in various fields, and stable images can be always produced in various environments. There is an even more strict requirement to provide.

Electrophotographic photoreceptors are required to have durability against electrical and mechanical external forces because they are directly applied. Specifically, it is required to have durability against abrasion and scratches on the surface due to rubbing, and deterioration of the surface layer due to attachment of active substances such as ozone and nitrogen oxides generated during charging.

Further, the electrophotographic photosensitive member is repeatedly subjected to steps such as charging, exposure, development, transfer, cleaning and charge removal. The electrostatic latent image formed by charging and exposure becomes a toner image by the toner. Further, this toner image is transferred to a transfer material such as paper by a transfer means, but not all the toner is transferred, and a part thereof remains as a residual toner on the electrophotographic photosensitive member.

If the amount of this residual toner is large, that is,
When the transfer failure occurs, the image on the transfer material is in a so-called "blurred" shape, and not only the image uniformity is lacked but also there is a problem that the toner is fused to the electrophotographic photosensitive member and filming occurs. For these problems, it is required to improve the releasability of the surface layer of the electrophotographic photosensitive member.

Attempts have been made to provide various protective layers to meet the above requirements. Among various attempts, many protective layers containing a resin (binder resin) as a main component have been proposed. For example, JP-A-57-30846 discloses a protective layer capable of controlling the volume resistivity by adding a metal oxide as conductive particles to a binder resin.

Further, Japanese Patent Publication No. 6-82223 discloses that
It has been proposed to use a curable phenol resin as the resin for the protective layer. However, in the electrophotographic photoreceptor described in this publication, carbon fluoride is dispersed in the protective layer, so that the transparency of the resin in the protective layer is lowered and the one-dot reproducibility of an image is poor.

Dispersing the metal oxide in the protective layer of the electrophotographic photosensitive member controls the volume resistivity of the protective layer itself and prevents an increase in residual potential in the electrophotographic photosensitive member due to repeated electrophotographic processes. Is the main purpose, and the preferred volume resistivity of the protective layer of the electrophotographic photosensitive member is 10 ¹⁰ to ¹⁰ 10.
It is known to be ¹⁵ Ω · cm.

However, with the volume resistivity in the above range, the volume resistivity of the protective layer is easily affected by ion conduction, and therefore the volume resistivity tends to largely change due to changes in the environment. In particular, when the metal oxide is dispersed in the protective layer, the volume of the protective layer is increased in the entire environment because the water absorption of the surface of the metal oxide is high and when the electrophotographic process is repeated. Until now, it has been very difficult to maintain the resistivity within the above range.

In particular, under high humidity, the volume resistivity gradually decreases when left standing, and the active substances such as ozone and nitrogen oxides generated by electrification are repeatedly attached to the surface, resulting in electron emission. The volume resistivity of the surface layer of the photographic photosensitive member is lowered, the releasing property of the toner from the surface layer is lowered, defects such as so-called image deletion and image blur occur, and the image uniformity becomes insufficient. There was a problem.

In general, when the particles are dispersed in the protective layer, the particle diameter of the particles should be smaller than the wavelength of the incident light, in order to prevent scattering of the incident light by the dispersed particles, that is,
It is preferably 0.3 μm or less.

However, since the metal oxide particles usually tend to aggregate in the resin solution, it is difficult to uniformly disperse them, and even if they are once dispersed, secondary aggregation or precipitation easily occurs, so that the particle diameter is 0.3 μm or less. It was very difficult to stably produce a good dispersion film of such fine particles.

Further, from the viewpoint of improving the transparency and the uniformity of conductivity of the protective layer, it is preferable to disperse ultrafine particles having a particularly small particle size (primary particle size of 0.1 μm or less). Property and dispersion stability tended to become worse.

In order to make up for the above drawbacks, for example, Japanese Patent Laid-Open No.
No. 306857 discloses a fluorine atom-containing silane coupling agent, a titanate coupling agent or C ₇ F.
A protective layer containing a compound such as ₁₅ NCO is disclosed in Japanese Patent Laid-Open No.
Japanese Patent Laid-Open No. 2-50167 discloses a protective layer in which fine metal particles or fine metal oxide particles having improved dispersibility and moisture resistance are dispersed in a binder resin by water repellent treatment. Discloses a protective layer in which a titanate coupling agent, a fluorine atom-containing silane coupling agent, and metal oxide fine particles surface-treated with acetoalkoxyaluminum diisopropylate are dispersed in a binder resin.

As an example of containing a charge transporting substance having a hydroxyl group in the protective layer, Japanese Patent Laid-Open No. 10-228 is known.
No. 126 and Japanese Patent Application Laid-Open No. 10-228127.

Further, as an example in which a phenol resin is used as the binder resin used in the protective layer, there is disclosed in Japanese Patent Laid-Open No. 5-18129.
It is disclosed in Japanese Patent Publication No. 9 and the like.

However, even with these protective layers, durability against various impacts on the surface, occurrence of abrasion and scratches, and releasability so as to meet recent demands for high durability and high image quality. Is not obtained at present.

Further, the need for space saving is increasing, and the necessity of reducing the size of the main body of the electrophotographic apparatus is pressing. Therefore, it is necessary to manufacture an electrophotographic photosensitive member that matches the size of the main body, and it is essential to reduce the diameter of the electrophotographic photosensitive member.

However, in line with the above needs, it is necessary to prepare both an electrophotographic photosensitive member having a protective layer that is harder than conventional ones and has abrasion resistance, and further to reduce the diameter of the electrophotographic photosensitive member. If so, there is a very big problem.

The electrophotographic photosensitive member having a diameter generally used in the past does not pose a problem so much, but due to the reduction in the diameter, a large stress is applied to the protective layer, and the electrophotographic photosensitive member is mounted on the electrophotographic apparatus. Occasionally, a load is applied from a member such as a charging unit, a developing unit, and a transfer unit, which is in direct contact with the electrophotographic photosensitive member, resulting in a problem that the protective layer is peeled off from a small scratch formed during the process. Resulting in. This problem becomes more remarkable when a curable resin is used as the binder resin of the protective layer.

Further, since the electrophotographic photosensitive member has a small diameter, it takes more rotation than a normal electrophotographic photosensitive member to output one image, and the electrophotographic photosensitive member is further loaded. .

Further, when the elastic deformation rate of the protective layer is made small in order to relieve the stress, the external additive of the toner adhering to the protective layer rotates while dragging, which causes deep scratches. , It no longer serves as a protective layer.

Furthermore, during image output, the temperature inside the electrophotographic apparatus tends to rise, the electrophotographic photosensitive member also rises in temperature in accordance with the temperature inside the electrophotographic apparatus, and the coefficient of thermal expansion of the protective layer and the photosensitive layer. Due to the difference between the two, the adhesion between the protective layer and the photosensitive layer becomes poor. At this time, if a load is applied to the electrophotographic photosensitive member, the protective layer peels off from the photosensitive layer because of poor adhesion.

[0025]

[Patent Document 1] JP-A-57-30846

[Patent Document 2] Japanese Patent Publication No. 6-82223

[Patent Document 3] Japanese Patent Application Laid-Open No. 1-306857

[Patent Document 4] Japanese Patent Laid-Open No. 62-295066

[Patent Document 5] Japanese Unexamined Patent Publication No. 2-50167

[Patent Document 6] Japanese Patent Laid-Open No. 10-228126

[Patent Document 7] Japanese Patent Laid-Open No. 10-228127

[Patent Document 8] JP-A-5-181299

[0026]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above problems, and even if a photosensitive layer and a protective layer are formed on a cylindrical support having a small diameter, peeling or fusion of the protective layer occurs. It is an object of the present invention to provide an electrophotographic photosensitive member having a protective layer having no scratches and excellent in abrasion resistance, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus.

[0027]

As a result of intensive studies, the present inventors have found that in an electrophotographic photosensitive member having a photosensitive layer and a protective layer on a support having a small diameter, the coefficient of thermal expansion measured from above the protective layer It has been found that the above problems can be solved if the difference from the coefficient of thermal expansion measured after removing the protective layer and the elastic deformation rate measured from above the protective layer are within a specific range.

That is, the present invention provides an electrophotographic photoreceptor having a photosensitive layer and a protective layer in this order on a cylindrical support, and the outer diameter of the cylindrical support is less than 30 mm. Difference (| α ₁ −α) between the coefficient of thermal expansion (α ₁ ) measured from the above and the coefficient of thermal expansion (α ₂ ) measured after removing the protective layer.
₂ |) is larger than 5.0 × 10 ⁻⁷ [° C. ⁻¹ ] and 1.
The electron is less than 0 × 10 ⁻⁴ [° C. ⁻¹ ] and the elastic deformation rate (We%) measured from above the protective layer is greater than 30% and less than 60%. It is a photographic photoreceptor.

In the present invention, the electrophotographic photosensitive member and at least one means selected from the group consisting of charging means, developing means, transfer means and cleaning means are integrally supported and attached to and detached from the main body of the electrophotographic apparatus. A process cartridge which can be freely used, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member.

Further, the present invention is an electrophotographic apparatus having an electrophotographic photoreceptor, a charging means, an exposing means, a developing means and a transferring means, wherein the electrophotographic photoreceptor is the above electrophotographic photoreceptor. It is an electrophotographic device that does.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below.

In the present invention, the coefficient of thermal expansion was measured using TMA / SS150 manufactured by Seiko Denshi Kogyo. The TMA / SS150 is a device for examining dimensional changes due to thermal expansion and contraction of a sample, and can measure expansion coefficient / expansion coefficient, glass transition, softening, swelling, stress / strain and stress relaxation.

In measuring the coefficient of thermal expansion by TMA / SS150, taking into consideration the shape of the electrophotographic photosensitive member, the measurement in the needle penetration mode was selected, and the load was 500 mN and the needle and the photosensitive layer were 49.
A constant pressure of 03 mN was applied and the up and down movement of the needle when the sample was expanded was plotted. Further, the temperature was raised from room temperature (23 ° C.) to 170 ° C. at a rate of 5 ° C./min.

In any case, the expansion of the sample was observed as the temperature was raised, and the glass transition point (T) of the photosensitive layer (in the case of the laminated type photosensitive layer, the charge transport layer; the same applies hereinafter) was measured.
It expanded proportionally up to g). Then, when the Tg of the photosensitive layer was exceeded, the photosensitive layer softened at once and the needle entered the photosensitive layer.

For this reason, the coefficient of thermal expansion in the present invention is obtained by drawing an approximate line and obtaining the slope thereof before the Tg of the resin of the photosensitive layer, that is, before the softening point, where the resin is proportionally expanded. When measuring from above the protective layer,
The total thickness of the protective layer and the photosensitive layer at room temperature was a value obtained by dividing the thickness of the photosensitive layer at room temperature in the case of measurement after removing the protective layer.

By taking the difference between the value obtained by measuring the protective layer and the value obtained after removing the protective layer, the influence of the expansion of the layer below the support and the photosensitive layer is obtained. Can be ignored. Here, the layer below the photosensitive layer includes a charge generation layer when the photosensitive layer is a laminated type.

Further, in the present invention, mechanical peeling is employed when the protective layer is peeled off.

As described above, in the electrophotographic photosensitive member of the present invention, the difference between the coefficient of thermal expansion (α ₁ ) measured from above the protective layer and the coefficient of thermal expansion (α ₂ ) measured after removing the protective layer. (|
α ₁ -α ₂ |) is a larger 1.0 × less than ^{10 -4} [℃ ^-1] than ^{5.0 × 10 -7 [℃ -1]} .

The difference in coefficient of thermal expansion is 5.0 × 10
^{In the case of -7} [° C. ^-1 ] or less, when a member that comes into contact with the electrophotographic photosensitive member during image output, for example, the cleaning blade is in contact, the sound of the cleaning blade and the electrophotographic photosensitive member rubbing, so-called "squeaking" Grows larger.

Although the details of this problem have not been clarified yet,
Since the difference in the coefficient of thermal expansion between the protective layer and the photosensitive layer is small, even if the temperature inside the electrophotographic apparatus equipped with the electrophotographic photosensitive member rises, the protective layer and the photosensitive layer are too closely attached to each other, so that the contact member I think that it is because the power received from etc. is not well distributed.

On the other hand, the difference in coefficient of thermal expansion is 1.0 × 10.
^-4 [° C. ^-1 ] or more, when the temperature inside the machine rises to a certain temperature, the adhesion between the protective layer and the photosensitive layer deteriorates due to the difference in the coefficient of thermal expansion, and the curvature of the support of the electrophotographic photosensitive member decreases. Is large (the outer diameter of the support is small), the stress cannot be resisted and the protective layer is peeled off from the photosensitive layer.

The difference (| α ₁ -α ₂ |) between the coefficient of thermal expansion (α ₁ ) measured from above the protective layer and the coefficient of thermal expansion (α ₂ ) measured after removing the protective layer is 1.0 x 10
^-6 [℃ ^{- 1]} greater than 7.0 × ^{10 -5} [℃ ^-1]
It is preferably less than.

In the present invention, the elastic deformation rate is measured by a hardness meter Fischerscope H manufactured by Fischer GmbH, Germany.
100 was used. Hereinafter, this is called a Fischer hardness meter.

The measurement environment was 23 ° C./55% RH in all.

The elastic deformation rate measuring method adopted by the Fischer hardness meter is as in the conventional micro-Vickers method, in which an indenter is pushed into the surface of the sample and the residual dent after unloading is measured with a microscope to obtain the hardness. Instead of the method, when pushing the set load on the indenter stepwise and pushing it into the film,
In this method, the indentation depth under load is electrically detected and read to obtain continuous hardness.

Specifically, the elastic deformation rate was measured as follows.

A load is applied to the film to 1 μm by applying a load with a diamond indenter having a face-to-face angle of 136 ° with a quadrangular pyramid, and then the load is reduced to measure the indentation depth and the load until the load becomes zero.

Using the above Fischer hardness tester, 3 μm
FIG. 4 shows an example of measurement at the indentation depth of.

Point A is a measurement start point, and A → B is a curve corresponding to the pushing of the indenter. A point B is a point when the maximum set indentation depth is reached, and a curve B → C is a curve corresponding to “return” after the indenter is pushed. At this time, the elastic deformation work We (nJ) is C-in the figure.
It is represented by the area enclosed by B-D-C, and the work amount Wr (nJ) of plastic deformation is represented by the area enclosed by A-B-C-A in the figure.

The elastic deformation rate (We%) in the present invention is
It is calculated by the following formula.

We% = We / (We + Wr) × 100 In general, elasticity is a property in which an object strained (deformed) by an external force tries to restore the strain, and the object has an elastic limit. Even after removing the external force due to super or other effects, it remains as part of the strain,
It is a plastic component. That is, it means that the larger the value of We%, the larger the amount of elastic deformation, and the smaller the value of We%, the larger the amount of plastic deformation.

As described above, in the electrophotographic photosensitive member of the present invention, the elastic deformation rate (We%) measured from above the protective layer is
It is more than 30% and less than 60%.

When We% is 30% or less, it means that the elastic component in the protective layer is insufficient, the protective layer is brittle, and external additives of toner are pressed against the photosensitive layer during the image output process. , Cause scratches.

On the other hand, when We% is 60% or more, filming occurs under high humidity.

Although the details have not been clarified, if the elastic deformation is too large, various fine particles are embedded in the protective layer, and the plastic content is small, so that the fine particles cannot be removed well, and filming occurs from this position as a starting point. Is expected to exist.

The elastic deformation rate (We%) measured from above the protective layer is preferably more than 35% and less than 55%.

Further, the above-mentioned various problems occur remarkably when the member contacting the electrophotographic photosensitive member is strongly hit by the electrophotographic photosensitive member in the image forming process. Therefore, in a system in which the charging means is a contact charging means having a charging member disposed in contact with the electrophotographic photosensitive member, and the charging member is a member for charging the electrophotographic photosensitive member by applying only a DC voltage, In particular, it is important to satisfy the above-mentioned requirements for the coefficient of thermal expansion and the elastic deformation rate. Further, it becomes even more important in a system in which charged particles are present between the charging member and the electrophotographic photosensitive member.

The protective layer of the electrophotographic photosensitive member of the present invention is preferably a layer containing a binder resin and at least one of conductive particles and a charge transport substance.

As the binder resin for the protective layer, a curable resin is preferable, and among them, a phenol resin, an epoxy resin and a siloxane resin are more preferable. Further, among them, the phenol resin is preferable because the environmental change of the resistance of the protective layer is small. Further, in particular, the thermosetting resol-type phenol resin is more preferable because it has a high surface hardness, excellent abrasion resistance, and excellent dispersibility of fine particles and stability after dispersion.

The curable phenol resin is a resin generally obtained by the reaction of phenols and formaldehyde.

There are two types of phenolic resin,
It is classified into a resol type obtained by reacting an phenol with an excess of formaldehyde and an alkali catalyst, and a novolak type obtained by reacting an phenol with an excess of formaldehyde and an acid catalyst.

The resol type is also soluble in solvents such as alcohols and ketones, and when heated, it is three-dimensionally crosslinked and polymerized to form a cured product. 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 and industrially, the resol type is used as a varnish for paints, adhesives, cast products and laminated products, and the novolak type is mainly used as a molding material and a binder. .

In the present invention, as the phenol resin, both a resol type and a novolak type can be used, but it is preferable to use the resol type because of curing without adding a curing agent and operability as a paint. preferable.

When the phenolic resin is used in the present invention, one kind or two or more kinds of phenolic resins can be mixed and used, and a resol type and a novolak type can also be mixed and used. Any known phenol resin may be used.

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 are:
Examples include, but are not limited to, phenol, cresol, xylenol, paraalkylphenol, paraphenylphenol, resorcin and bisphenol.

Examples of aldehydes include, but are not limited to, formaldehyde, paraformaldehyde, furfural and acetaldehyde.

Monomers of phenols, dimethylolphenols, trimethylolphenols, and their mixtures, or their oligomerized products, and monomers are obtained by reacting these phenols with aldehydes under an alkaline catalyst. And a mixture of oligomers are made. Among them, a relatively large molecule having a repeating structural unit 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. Examples of the metal-based alkali compounds include water of alkali metals such as sodium hydroxide, potassium hydroxide and calcium hydroxide and alkaline earth metal. Examples of amine compounds such as oxides include, but are not limited to, ammonia, hexamethylenetetramine, trimethylamine, triethylamine and triethanolamine.

In the present invention, it is preferable to use an amine compound in consideration of the variation in resistance under a high humidity environment, but in consideration of other electrophotographic characteristics, one using a metal-based alkali compound is preferable. You may mix and use it.

The protective layer of the electrophotographic photosensitive member of the present invention is preferably formed by coating the photosensitive layer with a coating solution obtained by dissolving or diluting a curable phenol resin in a solvent,
As a result, a polymerization reaction occurs after coating and a cured layer is formed.

The form of polymerization is such that it proceeds by addition and condensation reactions by heat, and after coating the protective layer, heating causes the polymerization reaction to form a polymer cured layer in which the resin is cured. Is.

In the present invention, "the resin is cured" means that the resin does not dissolve even when the resin is wet with an alcohol solvent such as methanol or ethanol.

The conductive particles for the protective layer have an auxiliary role of adjusting the volume resistivity of the protective layer, and are not necessarily used if not necessary.

The conductive particles usable in the protective layer of the electrophotographic photosensitive member of the present invention include metals and metal oxides.

As the metal, aluminum, zinc, copper,
Examples include chromium, nickel, silver and stainless steel, or those obtained by vapor-depositing these metals on the surface of plastic particles.

Examples of the metal oxides include zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin-doped indium oxide, tin oxide doped with antimony or tantalum, and zirconium oxide doped with antimony. Is mentioned.

These may be used alone or in combination of two or more. When two or more kinds are used in combination, they may be simply mixed, or may be in the form of solid solution or fusion.

In the present invention, among the conductive particles,
A metal oxide is preferably used in terms of transparency. Furthermore, among these metal oxides, it is particularly preferable to use tin oxide. The tin oxide may be surface-treated as described below for the purpose of improving dispersibility and liquid stability, and may be doped with antimony or tantalum for the purpose of improving resistance controllability.

From the viewpoint of the transparency of the protective layer, the average particle diameter of the conductive particles for the protective layer is 0.3 μm or less, particularly 0.1 μm.
m or less is preferable. On the other hand, from the viewpoint of dispersibility and dispersion stability, it is preferably 0.001 μm or more.

From the viewpoint of the film strength of the protective layer, the larger the amount of the conductive particles, the weaker it becomes. Therefore, the amount of the conductive particles is small within the range where the volume resistivity and the residual potential of the protective layer are allowable. Is preferred.

The protective layer of the electrophotographic photosensitive member of the present invention is preferably a layer containing lubricating particles.

The lubricating particles for the protective layer are preferably fluorine atom-containing resin particles, silicone resin particles, silica particles and alumina particles, and more preferably fluorine atom-containing resin particles. Further, two or more of these may be mixed.

The fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluoroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin and difluorodichloroethylene resin. It is preferable to appropriately select one kind or two or more kinds from the particles and the resin particles of the copolymer of these resins, and the tetrafluoroethylene resin particles and the vinylidene fluoride resin particles are particularly preferable.

The molecular weight of the lubricating particles and the particle diameter of the particles can be appropriately selected and are not particularly limited.
The average molecular weight is preferably 3,000 to 5,000,000, the average particle diameter is preferably 0.01 to 10 μm, and further, the average particle diameter is 0.01.
05-2.0 μm is more preferable.

Inorganic particles such as silica particles and alumina particles may not function as lubricating particles as the particles alone, but by dispersing and adding them, the surface roughness of the protective layer increases, As a result, it has been clarified by the study of the present inventors that the lubricity of the protective layer is increased. In the present invention, the lubricity particles include particles that impart lubricity.

When the lubricating particles such as the fluorine atom-containing resin particles and the conductive particles are both dispersed in the resin solution,
It is advisable to add a fluorine atom-containing compound at the time of dispersing the conductive particles or to surface-treat the surface of the conductive particles with the fluorine atom-containing compound so as to prevent the mutual particles from aggregating.

By adding a fluorine atom-containing compound or subjecting the conductive particles to a surface treatment, the dispersibility of the conductive particles and the fluorine atom-containing resin particles in the resin solution and Dispersion stability is significantly improved.

Further, the fluorine atom-containing resin particles are dispersed in a liquid in which the fluorine atom-containing compound is added to disperse the conductive particles or a liquid in which the surface-treated conductive particles are dispersed. No secondary particles are formed, and a coating liquid with excellent dispersibility that is very stable over time can be obtained.

As the fluorine atom-containing compound, a fluorine-containing silane coupling agent, a fluorine-modified silicone oil,
Fluorine-based surfactants and the like can be mentioned.

Preferred specific examples are shown below, but the present invention is not limited to these compounds.

[0093]

[Outside 8]

[0094]

[Outside 9]

[0095]

[Outside 10]

As a method of surface-treating the conductive particles, the conductive particles and the surface-treating agent are mixed and dispersed in a suitable solvent,
A surface treatment agent is attached to the surface of the conductive particles. As a dispersing method, a usual dispersing means such as a ball mill or a sand mill can be used. Next, the solvent may be removed from this dispersion solution and fixed on the surface of the conductive particles.

If necessary, further heat treatment may be performed thereafter. Further, a catalyst for accelerating the reaction can be added to the treatment liquid. Further, if necessary, the surface-treated conductive particles can be further pulverized.

The ratio of the fluorine atom-containing compound to the conductive particles is affected by the particle size, shape, surface area, etc. of the particles, but is 1 with respect to the total mass of the surface-treated conductive particles.
˜65% by mass is preferable, and more preferably 1 to 50% by mass.

Further, in the present invention, in order to form a protective layer having more environmental stability, a siloxane compound having a structure represented by the following formula (1) is added at the time of dispersing conductive particles, or By mixing the conductive particles surface-treated with the siloxane compound having the structure represented by (1), a protective layer having more excellent environmental stability can be obtained.

[0100]

[Outside 11]

(In the formula (1), A ^{11 to} A ¹⁸ are each independently a hydrogen atom or a methyl group.
The ratio (b / a) of the total number (b) of hydrogen atoms to the total number (a) is 0.001 or more and 0.5 or less. n ¹¹
Is an integer of 0 or more. The formation of secondary particles of dispersed particles is also possible by dispersing the coating liquid in which the siloxane compound is added or dispersed in the binder resin in which the conductive metal oxide particles surface-treated with the siloxane compound are dissolved in a solvent. In addition, a coating liquid that is stable and has good dispersibility over time can be obtained, and the protective layer formed from this coating liquid has high transparency and is particularly excellent in environmental resistance.

The molecular weight of the siloxane compound having the structure represented by the above formula (1) is not particularly limited, but when the surface treatment is performed, it is better that the viscosity is not too high because of its easiness. Average molecular weight 100-5000
0 is preferable, and in particular, 500 to 10,000 is preferable from the viewpoint of the treatment efficiency of the surface treatment.

As the method of surface treatment, there are two methods, wet type and dry type.
There is a street.

In the wet treatment, conductive metal oxide particles which are conductive particles are dispersed in a solvent together with a siloxane compound having a structure represented by the above formula (1), and the siloxane compound is attached to the surface of fine particles. .

As a dispersing means, a general dispersing means such as a ball mill or a sand mill can be used. Next, this dispersion solution is fixed to the surface of the conductive metal oxide particles.

In this heat treatment, S in siloxane
The i-H bond is oxidized by hydrogen in the air during the heat treatment to oxidize a hydrogen atom, thereby forming a new siloxane bond. As a result, siloxane develops into a three-dimensional structure,
The surface of the conductive metal oxide particles is surrounded by this network structure.

Thus, the surface treatment is completed by fixing the siloxane compound to the surface of the conductive metallized particles, but the particles after the treatment may be subjected to a pulverization treatment, if necessary.

In the dry process, the siloxane compound is adhered to the particle surface by mixing the siloxane compound and the conductive metal oxide particles and kneading without using a solvent. After that, heat treatment and crushing treatment are performed in the same manner as the wet treatment to complete the surface treatment.

As the charge transporting substance which can be used in the protective layer of the electrophotographic photosensitive member of the present invention, compounds having at least one hydroxyl group in the molecule are preferable, and particularly, hydroxyalkyl group, hydroxyalkoxyl group, Alternatively, a compound having at least one hydroxyphenyl group is preferable.

As the charge transporting substance having at least one of a hydroxyalkyl group and a hydroxyalkoxyl group in the molecule, a charge transporting substance having a structure represented by any one of the following formulas (2) to (4) is preferable.

[0111]

[Outside 12]

(In the formula (2), R ²¹ , R ²² and R
Each ²³ independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched. The benzene rings of α, β and γ are each independently a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or
It may have a substituted or unsubstituted aromatic heterocyclic group as a substituent. a, b, d, m and n each independently represent 0 or 1. )

[Outside 13]

(In the formula (3), R ³¹ , R ³² and R
Each ³³ independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched. The benzene rings of δ and ε are each independently a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group,
It may have a substituted or unsubstituted aromatic hydrocarbon ring group or a substituted or unsubstituted aromatic heterocyclic group as a substituent. e, f and g are each independently 0 or 1
Indicates. p, q, and r are independently 0 or 1, but not all are 0 at the same time. Z ³¹
And Z ³² are each independently a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted aromatic heterocyclic group. It may represent a ring group or may jointly form a ring. )

[Outside 14]

(In the formula (4), R ⁴¹ , R ⁴² , R ⁴³ and R ⁴⁴ each independently represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched. , Θ and ι benzene rings are each independently a halogen atom,
It may have a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted aromatic heterocyclic group as a substituent. h, i, j, k, s, t and u each independently represent 0 or 1. Z ⁴¹ and Z ⁴² are each independently a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted aromatic group. It may represent a group heterocyclic group or may form a ring together. The charge transporting substance having a hydroxyphenyl group in the molecule is preferably a charge transporting substance having a structure represented by any one of the following formulas (5) to (7).

[0115]

[Outside 15]

(In the formula (5), R ⁵¹ represents a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched.
⁵² represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted phenyl group. Ar ⁵¹ and Ar ⁵² are
Each independently represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted aromatic heterocyclic group. Ar ⁵³ represents a substituted or unsubstituted divalent aromatic hydrocarbon ring group or a substituted or unsubstituted divalent aromatic heterocyclic group. v and w each independently represent 0 or 1. However, when v = 0, w =
It is 0. The benzene rings of κ and λ are each independently a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted You may have an aromatic heterocyclic group as a substituent. )

[Outside 16]

[0117] (In the formula ^{(6), R 61} is, ^{.Ar 61} showing a divalent hydrocarbon group which may be branched C1-8
And Ar ⁶² each independently represent a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted aromatic heterocyclic group. Show. x represents 0 or 1. The μ and ν benzene rings are each independently a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted It may have an aromatic heterocyclic group as a substituent, or the benzene rings of μ and ν may jointly form a ring via a substituent. )

[Outside 17]

(In the formula (7), R ⁷¹ and R ⁷² each independently represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched. Ar ⁷¹ is a substituted or unsubstituted group. An alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted aromatic heterocyclic group, y and z are each independently 0 or 1 The benzene rings of ξ, π, ρ and σ are each independently a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, Alternatively, it may have a substituted or unsubstituted aromatic heterocyclic group as a substituent, a benzene ring of ξ and π, and ρ and σ
The benzene rings of may independently form a ring through a substituent. ) In the above formula ^{(2) ~ (7),} R 21, R 22, R 23, R
³¹ , R ³² , R ³³ , R ⁴¹ , R ⁴² , R ⁴³ , R
⁴⁴ , R ⁵¹ , R ⁶¹ , R ⁷¹ and R ⁷² have 1 carbon atom
Examples of the divalent hydrocarbon group which may be branched are
Examples thereof include alkylene groups such as methylene group, ethylene group, propylene group and butylene group, isopropylene group, cyclohexylidene group and the like.

Examples of the alkyl group of R ⁵² include a methyl group, an ethyl group, a propyl group and a butyl group, and examples of the aralkyl group include a benzyl group, a phenethyl group and a naphthylmethyl group.

Further, α, β, γ, δ, ε, ζ, η, θ,
Of the substituents that the benzene ring of ι, κ, λ, μ, ν, ξ, π, ρ and σ may have, the halogen atom is:
Examples thereof include a fluorine atom, chlorine atom, bromine atom and iodine atom, examples of the alkyl group include a methyl group, ethyl group, propyl group and butyl group, and examples of the alkoxyl group include a methoxy group, an ethoxy group and a propoxy group. And butoxy group, and the like, the aromatic hydrocarbon ring group includes phenyl group, naphthyl group, anthryl group and pyrenyl group, and the like, and the aromatic heterocyclic group includes pyridyl group, thienyl group, furyl group and Examples thereof include a quinolyl group.

When the benzene ring of μ and ν, the benzene ring of ξ and π, and the benzene ring of ρ and σ jointly form a ring through a substituent, the substituent is a propylidene group. , An ethylene group, and the like, and form a cyclic structure such as a fluorene skeleton or a dihydrophenanthrene skeleton through these groups.

Further, Z ³¹ , Z ³² , Z ⁴¹ and Z
^As the halogen atom of ⁴² , a fluorine atom, a chlorine atom,
Examples of the bromine atom and iodine atom, the alkyl group include a methyl group, an ethyl group, a propyl group and a butyl group, and the alkoxyl group includes a methoxy group, an ethoxy group, a propoxy group and a butoxy group. The aromatic hydrocarbon ring group includes a phenyl group, a naphthyl group, an anthryl group and a pyrenyl group, and the aromatic heterocyclic group includes a pyridyl group, a thienyl group, a furyl group and a quinolyl group. .

Further, Ar ⁵¹ , Ar ⁵² , Ar ⁶¹ , A
Examples of the alkyl group of r ⁶² and Ar ⁷¹ include a methyl group, an ethyl group, a propyl group and a butyl group, and examples of the aralkyl group include a benzyl group, a phenethyl group and a naphthylmethyl group. Examples of the cyclic group include a phenyl group, naphthyl group, anthryl group and pyrenyl group, and examples of the aromatic heterocyclic group include a pyridyl group, a thienyl group, a furyl group and a quinolyl group.

Examples of the divalent aromatic hydrocarbon ring group of Ar ⁵³ include a phenylene group, a naphthylene group, an anthrylene group and a pyrenylene group. Examples of the divalent aromatic heterocyclic group include a pyridylene group and a pyridylene group. Examples thereof include a thienylene group.

The substituent which each of the above groups may have is as follows:
Methyl group, ethyl group, alkyl group such as propyl group and butyl group, benzyl group, aralkyl group such as phenethyl group and naphthylmethyl group, phenyl group, naphthyl group, anthryl group, pyrenyl group, fluorenyl group, carbazolyl group, Aromatic hydrocarbon ring group such as dibenzofuryl group and dibenzothiophenyl group, aromatic heterocyclic group, alkoxyl group such as methoxy group, ethoxy group and propoxy group, aryloxy group such as phenoxy group and naphthoxy group, Examples thereof include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, and nitro group and cyano group.

The charge-transporting substance having the structure represented by any one of the above formulas (2) to (7) has good compatibility with the phenol resin and facilitates formation of a uniformly dispersed protective layer film. Can be made.

In order to further improve the compatibility,
R ²¹ , R ²² , R ²³ , and R in the above formulas (2) to (4).
³¹ , R ³² , R ³³ , R ⁴¹ , R ⁴² , R ⁴³ , R
The divalent hydrocarbon group of ⁴⁴ preferably has 4 or less carbon atoms, and the number of hydroxyalkyl groups and hydroxyalkoxyl groups is preferably 2 or more.

In the above formulas (5) to (7),
The hydroxyphenyl group contained in the charge transport material reacts with the phenolic resin, the charge transport material is taken into the protective layer matrix, and the strength as the protective layer becomes stronger.

The charge-transporting substance having the structure represented by any one of the above formulas (2) to (7) is uniformly dissolved or dispersed in the coating liquid for forming the protective layer, and applied. Form.

The mixing ratio of the charge transporting material having the structure represented by any one of the above formulas (2) to (7) and the binder resin is a mass ratio of charge transporting material / binder resin = 0.1. / 10
To 20/10 are preferable, and especially 0.5 / 10 to 10 /
10 is more preferable. If the amount of the charge transport material is too small with respect to the binder resin, the effect of lowering the residual potential becomes small, and if it is too large, the strength of the protective layer may be weakened.

Specific examples (compound examples) of the charge transport material having the structure represented by any one of the above formulas (2) to (7) will be shown below. However, the present invention is not limited to these.

[0132]

[Outside 18]

[0133]

[Outside 19]

[0134]

[Outside 20]

[0135]

[Outside 21]

[0136]

[Outside 22]

[0137]

[Outside 23]

[0138]

[Outside 24]

[0139]

[Outside 25]

[0140]

[Outside 26]

[0141]

[Outside 27]

[0142]

[Outside 28]

[0143]

[Outside 29]

[0144]

[Outside 30]

Among these, (3), (4),
(5), (8), (11), (12), (13), (1
7), (21), (24), (25), (26), (2
7), (28), (30), (31), (34), (3
5), (39), (44), (48), (49), (5
0), (52), (55), (56), (58), (5
9) is preferable, and further, (3), (8), (1
2), (25), (31), (39), (44), (4
9) and (56) are more preferable.

As a solvent for dispersing the coating liquid for the protective layer,
The binder resin is sufficiently dissolved, the charge transport substance having the structure represented by the formulas (2) to (7) is also sufficiently dissolved, and when the conductive particles are used, the dispersibility thereof is good, and the fluorine atom-containing compound is used. In the case of using fluorine atom-containing resin particles and lubricating particles such as siloxane compounds, a solvent having good compatibility and processability and having no adverse effect on the charge transport layer in contact with the coating liquid for the protective layer is preferable.

Therefore, as the solvent, methanol,
Alcohols such as ethanol and 2-propanol, ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, ethers such as tetrahydrofuran and dioxane,
Aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as chlorobenzene and dichloromethane, and the like can be used, and these may be mixed and used. Among these, the most suitable solvents for the form of phenol resin are methanol, ethanol and 2
-Alcohols such as propanol.

Conventional charge-transporting substances are generally insoluble or sparingly soluble in alcohol solvents, and it is difficult to uniformly disperse them in general phenolic resins. However, most of the charge-transporting substances used in the present invention are difficult. Since is soluble in a solvent containing alcohols as a main component, it can be dispersed in a phenol resin coating liquid.

As the method for applying the protective layer of the electrophotographic photosensitive member of the present invention, general coating methods such as dip coating method, spray coating method, spinner coating method, roller coating method, Mayer bar coating method and blade coating method are used. Any method can be used.

If the protective layer of the electrophotographic photosensitive member of the present invention is too thin, the durability of the electrophotographic photosensitive member may be impaired, while if it is too thick, the residual potential increases due to the provision of the protective layer. 0.1 μm to 10 μm
Is preferable, and a range of 0.5 μm to 7 μm is more preferable.

In the present invention, an additive for an antioxidant is added to the above-mentioned protective layer for the purpose of preventing deterioration of the surface layer due to adhesion of active substances such as ozone and nitrogen oxides generated during charging. Good.

Next, the photosensitive layer and the like will be described below.

The photosensitive layer of the electrophotographic photosensitive member of the present invention preferably has a laminated structure. In the electrophotographic photosensitive member of FIG. 1A, a charge generation layer 3 and a charge transport layer 2 are sequentially provided on a support 4, and a protective layer 1 is further provided on the outermost surface.
Further, as shown in FIGS. 1B and 1C, an intermediate layer 5 and a conductive layer 6 for preventing interference fringes may be provided between the support and the charge generation layer.

The support for the electrophotographic photosensitive member of the present invention may have conductivity and has an outer diameter of less than 30 mm.
For example, a metal such as aluminum, an aluminum alloy, and stainless can be used. In addition, a support having a layer formed by vacuum deposition of aluminum, an aluminum alloy, an indium oxide-tin oxide alloy, or the like, a plastic, or a conductive material. A support in which particles (for example, carbon black, tin oxide, titanium oxide, silver particles, etc.) are impregnated into a plastic or paper together with a suitable binder resin,
A plastic having a conductive binder resin can be used.

An intermediate layer (adhesive layer) having a barrier function and an adhesive function can be provided between the support and the photosensitive layer. The intermediate layer is for improving the adhesiveness of the photosensitive layer, improving the coatability,
It is formed to protect the support, cover defects in the support, improve charge injection from the support, protect the photosensitive layer against electrical breakdown, and the like. The intermediate layer may be formed of casein, polyvinyl alcohol, ethyl cellulose, ethylene-acrylic acid copolymer, polyamide, modified polyamide, polyurethane, gelatin or aluminum oxide. The thickness of the intermediate layer is preferably 5 μm or less, and particularly preferably 0.1 to 3 μm.

The charge generating substance used in the electrophotographic photoreceptor of the present invention includes (1) azo pigments such as monoazo, disazo and trisazo, (2) phthalocyanine pigments such as metal phthalocyanine and non-metal phthalocyanine, and (3 ) Indigo pigments such as indigo and thioindigo, (4) perylene pigments such as perylene anhydride and perylene imide, (5) polycyclic quinone pigments such as anthraquinone and pyrenequinone, (6) squarylium dye, (7) ) Pyrylium salts and thiapyrylium salts, (8) triphenylmethane dyes, (9) inorganic substances such as selenium, selenium-tellurium and amorphous silicon, (10) quinacridone pigments, (11) azurenium salt pigments, (12) cyanine dyes , (13) xanthene dye, (14) Non'imin dye, (15) styryl dyes, (16) cadmium sulfide, and (17) and zinc oxide.

Of these, when a thermosetting resin is used for the protective layer, a phthalocyanine-based pigment is preferred because it has high heat resistance and relatively easily maintains sensitivity even after heating.

Examples of the binder resin used in the charge generation layer include polycarbonate resin, polyester resin, polyarylate resin, butyral resin, polystyrene resin,
Polyvinyl acetal resin, diallyl phthalate resin,
Examples thereof include acrylic resin, methacrylic resin, vinyl acetate resin, phenol resin, silicone resin, polysulfone resin, styrene-butadiene copolymer resin, alkyd resin, epoxy resin, urea resin and vinyl chloride-vinyl acetate copolymer resin. However, the present invention is not limited to these. These may be used alone, in the form of a mixture or in the form of a copolymer, or two or more types thereof may be used.

The solvent used for the charge generation layer coating liquid is selected from the solubility and dispersion stability of the resin and charge generation substance used, but as the organic solvent, alcohols, sulfoxides, ketones and ethers are used. It is possible to use compounds, esters, aliphatic halogenated hydrocarbons or aromatic compounds.

In the case where the photosensitive layer has a laminated structure, the charge generation layer contains a homogenizer, an ultrasonic wave, a ball mill, the charge generation substance together with 0.3 to 4 times the amount of the binder resin and the solvent.
It is formed by sufficiently dispersing with a method such as a sand mill, an attritor or a roll mill, coating and drying. The film thickness is preferably 5 μm or less, and particularly preferably in the range of 0.01 to 1 μm.

Further, various sensitizers, antioxidants, ultraviolet absorbers, plasticizers and known charge generating substances can be added to the charge generating layer as required.

As the charge transport material used in the electrophotographic photoreceptor of the present invention, various triarylamine compounds,
Examples include various hydrazone compounds, various styryl compounds, various stilbene compounds, various pyrazoline compounds, various oxazole compounds, various thiazole compounds and various triarylmethane compounds.

When the photosensitive layer has a laminated structure, the binder resin used to form the charge transport layer is an acrylic resin, a styrene resin, a polyester resin, a polycarbonate resin, a polyarylate resin, a polysulfone resin or a polyphenylene oxide. Resins, epoxy resins, polyurethane resins, alkyd resins and unsaturated resins are preferred, and further polymethylmethacrylate, polystyrene, styrene-acrylonitrile copolymers, polycarbonate resins and diallylphthalate resins are preferred.

The charge transport layer is generally formed by dissolving the charge transport substance and the binder resin in a solvent and coating the solution. The mixing ratio of the charge transport material and the binder resin is about 2: 1 to 1: 2. As the solvent, ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, and chlorinated hydrocarbons such as chlorobenzene, chloroform and carbon tetrachloride are used. To be When applying this solution, for example, a coating method such as a dip coating method, a spray coating method and a spinner coating method can be used, and drying is performed at 10
℃ ~ 200 ℃ is preferable, more preferably 20 ℃ ~ 15
It can be carried out at a temperature in the range of 0 ° C., preferably for 5 minutes to 5 hours, more preferably for 10 minutes to 2 hours under blast drying or static drying.

The charge transport layer is electrically connected to the above charge generation layer, receives charge carriers injected from the charge generation layer in the presence of an electric field, and transfers these charge carriers to the interface with the protective layer. It has the function of transporting.

Since this charge transport layer has a limit for transporting charge carriers, the film thickness cannot be increased more than necessary, but it is preferably 5 to 40 μm, and particularly 7 to 30 μm.
Is preferred.

Further, an antioxidant, an ultraviolet absorber, a plasticizer and a known charge transporting substance can be added to the charge transporting layer as required.

Further, the present invention is completed by applying the above-mentioned protective layer on the charge transport layer, curing the same, and forming a film.

Specific embodiments of an electrophotographic apparatus using the electrophotographic photosensitive member of the present invention will be shown below.

<Embodiment 1> FIG. 2 shows a schematic structure of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.

In FIG. 2, reference numeral 11 is a drum-shaped electrophotographic photosensitive member of the present invention, which is rotationally driven around the shaft 12 in the direction of the arrow at a predetermined peripheral speed.

In the rotating process, the electrophotographic photosensitive member 11 is uniformly charged to its peripheral surface by a (primary) charging means 13 at a predetermined positive or negative potential, and then subjected to exposure such as slit exposure or laser beam scanning exposure. The exposure light 14 intensity-modulated corresponding to the time-series electric digital image signal of the target image information output from the means (not shown) is received. In this way, electrostatic latent images corresponding to target image information are sequentially formed on the peripheral surface of the electrophotographic photosensitive member 11.

The electrostatic latent image thus formed is then developed by the developing means 1.
5, the toner is developed with toner, and the electrophotographic photosensitive member 11 is provided between the electrophotographic photosensitive member 11 and the transfer unit 16 from a paper feeding unit (not shown).
Of the transfer material 17 taken out and fed in synchronization with the rotation of the
Then, the toner images formed and carried on the surface of the electrophotographic photosensitive member 11 are sequentially transferred by the transfer unit 16.

The transfer material 17 that has received the transfer of the toner image is
After being separated from the surface of the electrophotographic photosensitive member, it is introduced into the fixing means 18 and subjected to image fixing, so that it is printed out to the outside of the apparatus as an image formed product (print, copy).

The surface of the electrophotographic photosensitive member 11 after the image transfer is
The cleaning unit 19 removes the transfer residual toner to make the surface clean. Further, it is also possible to directly collect the residual toner after transfer by a developing means or the like without providing a cleaning means (cleanerless). Further, after the charge is removed by the pre-exposure light 20 from the pre-exposure means (not shown), it is repeatedly used for image formation. The charging means 1
If 3 is a contact charging means using a charging roller or the like, pre-exposure is not always necessary.

In the present invention, among the above-mentioned electrophotographic photosensitive member 11, charging means 13, developing means 15, cleaning means 19 and the like, a plurality of components are housed in a container and integrally combined as a process cartridge. Alternatively, the process cartridge may be detachably attached to the main body of the electrophotographic apparatus such as a copying machine or a laser beam printer. For example, the charging unit 13 and the developing unit 1
5 and at least one of the cleaning means 19 are integrally supported together with the electrophotographic photosensitive member 11 to form a cartridge, and the guide cartridge 22 such as a rail of the apparatus main body is used to form the process cartridge 21 which is detachable from the apparatus main body. it can.

When the electrophotographic apparatus is a copying machine or a printer, the exposure light 14 is reflected light or transmitted light from the original, or the original is read by a sensor, converted into a signal, and the exposure is performed according to this signal. Light emitted by scanning a laser beam, driving an LED array, driving a liquid crystal shutter array, or the like. Also, other auxiliary processes may be added if necessary.

<Embodiment 2> FIG. 3 shows a schematic structure of an electrophotographic apparatus having a process cartridge having a charged particle supply means and having the electrophotographic photosensitive member of the present invention.

The drum-shaped electrophotographic photosensitive member 31 is rotationally driven at a constant speed in the arrow direction.

The charging roller 32 included in the charging means is composed of charged particles 33 (conductive particles for charging the electrophotographic photosensitive member), a medium resistance layer 32b as a particle carrier and a cored bar 32a. The charging roller 32 comes into contact with the electrophotographic photosensitive member 31 with a predetermined amount of penetration, and the contact portion n
To form.

The charging roller 32 in this embodiment is
A medium resistance layer 32b of rubber or foam is formed on a cored bar 32a, and charged particles 33 are further carried on the surface layer thereof.

The medium resistance layer 32b is formulated with a resin (for example, urethane), conductive particles (for example, carbon black), a sulfiding agent and a foaming agent, and is formed in a roller shape on the cored bar 32a. Then, the surface is polished.

The charging roller of this embodiment is the charging roller of the first embodiment (charging roller for discharging).
However, the following points are particularly different. (1) Surface structure and roughness characteristics for supporting high-density charged particles on the surface layer (2) Resistance characteristics required for injection charging (volume resistivity, surface resistance) The surface of the charging roller for discharge is flat. The average surface roughness Ra is sub-μm or less, and the roller hardness is also high. In charging using discharge, the discharge phenomenon occurs in a gap of several tens of μm, which is slightly apart from the contact portion between the charging roller and the electrophotographic photosensitive member. When unevenness exists on the surface of the charging roller and the electrophotographic photosensitive member, the electric field strength is partially different and the discharge phenomenon becomes unstable, resulting in uneven charging. Therefore, the charging roller for discharging needs a flat and hard surface.

The reason why the charging roller for discharging cannot inject and charge is that the surface structure as described above seems to be in close contact with the drum, but the microscopic contact at the molecular level necessary for charge injection is necessary. In terms of sex, there is almost no contact.

On the other hand, the charging roller 32 for injection charging is
Since it is necessary to carry the charged particles 33 at a high density, some roughness is required. The average roughness Ra is 1 μm to 500
μm is preferred. When the thickness is less than 1 μm, the surface area for supporting the charged particles 33 is insufficient, and when an insulator (for example, toner) adheres to the roller surface layer, it becomes difficult to contact the periphery of the roller with the electrophotographic photosensitive member 31, and the charging performance deteriorates. Easier to do. On the other hand, when it exceeds 500 μm, the unevenness on the surface of the charging roller tends to reduce the in-plane charging uniformity of the electrophotographic photosensitive member.

To measure the average roughness Ra, the shape of the roller surface and Ra can be measured in a non-contact manner using a surface shape measuring microscope VF-7500, VF7510 manufactured by Keyence Corporation and an objective lens of 1250 times to 2500 times. it can.

In the charging roller for discharging, a low resistance base layer is formed on a core metal, and then the surface is covered with a high resistance layer. The roller charging due to electric discharge has a high applied voltage, and if there is a pinhole (exposure of the support due to damage to the film), the voltage drops to the periphery thereof, resulting in poor charging. Therefore, 1
It is preferably set to 0 ¹¹ Ω □ or more.

On the other hand, in the injection charging system, since charging at a low voltage is possible, it is not necessary to make the surface layer have high resistance, and the charging roller can be composed of a single layer. Rather, in injection charging, the surface resistance of the charging roller is 1
It is preferably 0 ⁴ to 10 ¹⁰ Ω. When it exceeds 10 ¹⁰ , the uniformity on the charged surface is deteriorated, unevenness due to rubbing of the charging roller appears as streaks in the halftone image, and deterioration of the image quality is easily seen. On the other hand, when it is less than 10 ⁴ , even in the case of injection charging, a peripheral voltage drop is likely to occur due to pinholes in the electrophotographic photosensitive member.

Further, regarding the volume resistivity, 10 ⁴ to 1
It is preferably in the range of 0 ⁷ Ω · cm. When it is less than 10 ^4, a voltage drop of the power source due to pinhole leakage is likely to occur. On the other hand, when it exceeds 10 ⁷ , it becomes difficult to secure the current necessary for charging, and the charging voltage is likely to decrease.

The resistance of the charging roller was measured by the following procedure.

The roller resistance was measured by applying electrodes to an insulating drum having an outer diameter of 30 mm so that a total pressure of 1 kg was applied to the core metal 32a of the charging roller 32. The electrode was measured by placing a guard electrode around the main electrode. The distance between the main electrode and the guard electrode was adjusted to about the thickness of the elastic layer 32b so that the main electrode had a sufficient width with respect to the guard electrode. In the measurement, +100 V was applied to the main electrode from the power source, the currents flowing through the ammeters Av and As were measured, and the volume resistivity and the surface resistance were measured, respectively.

In the injection charging method, it is important that the charging member functions as a flexible electrode. In the magnetic brush, this is realized by the flexibility of the magnetic particle layer itself. In the present embodiment, this is achieved by adjusting the elastic characteristics of the medium resistance layer 32b. Asker C hardness is preferably in the range of 15 to 50 degrees, and more preferably in the range of 25 to 40 degrees. If the hardness is too high, the required amount of penetration cannot be obtained and the contact portion n cannot be secured between the electrophotographic photosensitive member and the charging performance is deteriorated. Further, since the molecular level contact property of the substance cannot be obtained, the contact with the periphery thereof is hindered by the inclusion of foreign matter. On the other hand, if the hardness is too low, the shape deformation is not stable, so that the contact pressure with the body to be charged becomes uneven, and uneven charging occurs. Alternatively, charging failure occurs due to permanent deformation strain of the roller due to long-term storage.

The material of the charging roller 32 is EPD.
Examples thereof include M, urethane, NBR, silicone rubber, and a rubber material in which a conductive substance such as carbon black or metal oxide for resistance adjustment is dispersed in IR or the like. It is also possible to adjust the resistance by using an ion conductive material without dispersing the conductive substance. Thereafter, if necessary, surface roughness is adjusted and molding is performed by polishing or the like. Further, a structure having a plurality of layers with separated functions is also possible.

As a form of the roller, a porous structure is more preferable. It is also advantageous from a manufacturing point of view that the above-mentioned surface roughness can be obtained at the same time as molding the roller. The appropriate cell diameter of the foam is 1 to 500 μm. After foam molding, the surface of the porous body is exposed by polishing the surface, whereby the surface structure having the above-mentioned roughness can be produced.

The charging roller 32 is the electrophotographic photosensitive member 31.
A contact portion n is formed by arranging an intrusion amount with respect to the electrophotographic photosensitive member 31.
It is possible to contact the surface with a speed difference. Further, at the time of image recording of the printer, a predetermined charging bias is applied from the charging bias applying power source S1 to the charging roller 32, whereby the peripheral surface of the electrophotographic photosensitive member 1 is uniformly charged to a predetermined polarity and potential by the injection charging method. It is processed.

The charged particles 33 are added to the toner and accumulated, and are supplied to the charging roller 32 through the electrophotographic photosensitive member 31 together with the development of the toner.

As a supply means, the regulation blade 34 is brought into contact with the charging roller 32, and the charged particles 33 are held between the charging roller 32 and the regulation blade 34. Then, as the electrophotographic photosensitive member 31 rotates, a fixed amount of charged particles 33 are applied to the charging roller 32, and then reach the contact portion n between the charging roller 32 and the electrophotographic photosensitive member 31.

Further, the particle size of the charged particles 33 is preferably 10 μm or less in order to obtain high charging efficiency and charging uniformity.
In the present invention, the particle size when the charged particles form an aggregate is defined as the average particle size of the aggregate. The particle size was measured by observing with an electron microscope to 100
The volume particle size distribution was calculated with the maximum chord length in the horizontal direction, and 50% of the average particle size was determined.

There is no problem that the charged particles 33 exist not only in the state of primary particles but also in the state of agglomeration of secondary particles. Whatever the aggregated state, the form is not important as long as the aggregate can realize the function as the charged particles.

The charged particles 33 are preferably white or nearly transparent so as not to hinder the latent image exposure particularly when used for charging an electrophotographic photosensitive member. Further, considering that the charged particles are partially transferred from the electrophotographic photosensitive member 31 to the transfer material P, colorless or white particles are preferable in color recording. Further, light scattering by the charged particles 33 is caused during image exposure. In order to prevent it, the particle size is preferably equal to or smaller than the constituent pixel size, more preferably equal to or smaller than the toner particle size.
The lower limit of the particle diameter is considered to be 10 nm as a particle that can be stably obtained.

Reference numeral 36 is a developing device. Electrophotographic photoreceptor 1
The electrostatic latent image on the surface is developed by the developing device 36 at the developing portion a.
To be developed as a toner image. The developing device 36 is provided with a mixture of toner and charged particles.

Further, the electrophotographic apparatus (printer) of this embodiment is a toner recycling process, and the transfer residual toner remaining on the surface of the electrophotographic photosensitive member 31 after the image transfer is removed by a dedicated cleaning means (cleaner). Instead, it is temporarily collected by the charging roller 32 that counter-rotates with the rotation of the electrophotographic photosensitive member 31, and the orbited toner charge is normalized as it orbits around the outer periphery of the charging roller 32, and the electrophotographic photosensitive member is sequentially rotated. It is discharged to the body 31 and reaches the developing portion a, where it is collected and reused in the developing simultaneous cleaning in the developing means 36 having the magnet roller 36a and the developing sleeve 36b. S2 is a power source for applying a developing bias to the developing means 36.

Reference numeral 35 is a laser beam scanner (exposure means) including a laser diode, a polygon mirror and the like. The laser beam scanner 35 outputs laser light whose intensity is modulated corresponding to the time-series digital image signal of the target image information, and scans and exposes the uniformly charged surface of the electrophotographic photosensitive member 31 with the laser light. To do. The scanning exposure light L forms an electrostatic latent image on the surface of the electrophotographic photosensitive member 31 corresponding to the target image information.

Reference numeral 38 is a fixing means such as a heat fixing system.
The transfer material P that has been fed to the transfer contact portion b between the electrophotographic photosensitive member 31 and the transfer roller 37 and has received the transfer of the toner image on the electrophotographic photosensitive member 31 side is transferred from the surface of the electrophotographic photosensitive member 31. The toner is separated and introduced into the fixing unit 38, where the toner image is fixed and discharged as an image formed product (print / copy) to the outside of the apparatus. S3 is a power source for applying a transfer bias to the transfer roller 37.

Reference numeral 39 is a process cartridge. In this embodiment, the electrophotographic photosensitive member, the charging unit and the developing unit are integrally supported. The process cartridge 39 is attachable to and detachable from the main body of the electrophotographic apparatus by guide means such as a rail 40 provided in the electrophotographic apparatus.

The electrophotographic photoreceptor 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 applied to electrophotographic application fields such as CRT printers, LED printers, FAX machines, liquid crystal printers, and laser plate making.

[0207]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In addition, "part" in an Example shows a mass part.

Example 1 A solution prepared by dissolving 10 parts of a copolyamide resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) in a mixed solution of 60 parts of methanol / 40 parts of butanol was used as an aluminum cylinder having an outer diameter of 29 mm. It is applied by dip coating on the top and dried by heating at 90 ° C. for 10 minutes to give a film thickness of 0.
A conductive layer of 5 μm was formed.

Next, the characteristic X of CuKα represented by the following formula
Bragg angle (2θ ± 0.2 °) of 9.0 in line diffraction
4 parts of oxytitanium phthalocyanine pigment having strong peaks at 2 ° and 27.1 °,

[Outside 31]

A mixed solution consisting of 2 parts of polyvinyl butyral resin (trade name: S-REC BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 70 parts of cyclohexanone was placed in a sand mill at 10
After time-dispersed, 100 parts of ethyl acetate was added to prepare a charge generation layer coating liquid. This coating solution is applied onto the conductive layer by dip coating and dried by heating at 90 ° C. for 10 minutes to give a film thickness of 0.
A 17 μm charge generation layer was formed.

Next, 7 parts of a triarylamine compound represented by the following formula:

[Outside 32]

Polycarbonate (trade name: Iupilon Z
A solution prepared by dissolving 10 parts of -200, manufactured by Mitsubishi Gas Chemical Co., Inc. in 70 parts of chlorobenzene is dip-coated on the charge generation layer, and dried by heating at 110 ° C. for 1 hour to give a film thickness of 20 μm. Was formed on the charge transport layer.

Next, 50 parts of antimony-doped tin oxide ultrafine particles surface-treated with a compound having a structure represented by the following formula for the protective layer (treatment amount: 7%):

[Outside 33]

150 parts of ethanol was mixed with a sand mill 6 times.
Dispersion was performed for 6 hours (average particle size 0.03 μm).
After that, resol type phenol resin (trade name: PL-4
804; manufactured by Gunei Chemical Industry Co., Ltd., using an amine-based catalyst (amine compound). ) As the resin component
A solution was prepared by dissolving 0 part of the mixture, a film was formed on the charge transport layer by a dip coating method, and dried with hot air at a temperature of 145 ° C. for 1 hour to obtain an electrophotographic photoreceptor having a protective layer. The state of dispersion of the protective layer coating solution was good, and the produced protective layer was a uniform and uniform film.

The We% of the obtained electrophotographic photosensitive member was measured and found to be 45.3 [%]. Also, | α ₁ −α
₂ | was 2.7 × 10 ⁻⁶ [° C. ⁻¹ ].

The evaluation was carried out using the following evaluation device.

<Evaluation apparatus 1> The electrophotographic photosensitive member thus produced was remodeled into a printer (Laserjet 4000) manufactured by Hewlett-Packard Company as follows (remodeled to have the construction of the apparatus of the second embodiment). It was attached to the device and evaluated.

For the charged portion of the electrophotographic photosensitive member, the charging roller was prepared by forming a medium resistance layer of rubber on the core metal. Here, the medium resistance layer is formulated with urethane resin, conductive particles (carbon black), a sulfiding agent, a foaming agent, etc., and is molded into a roller shape on a cored bar, and then the surface is polished to have a diameter of 12 mm and a longitudinal length. A 250 mm thick elastic conductive roller was produced. When the resistance of this roller was measured, it was 100 kΩ. 1 total pressure on the core of the roller
The measurement was performed by applying 100 V to the core metal and the support in a state where the electrophotographic photosensitive member was pressure-bonded so that a load of kg was applied.

In this evaluation apparatus, the charged particles for injection charging have a specific resistance of 10 ⁶ Ω · cm and an average particle size of 3 μm.
The conductive zinc oxide particles of

Further, in order to uniformly supply the charged particles to the contact portion between the charging roller and the electrophotographic photosensitive member, first, a charged particle applying means for applying the charged particles to the charging roller was provided. The regulation blade is brought into contact with the charging roller to hold the charged particles between the charging roller and the regulation blade. Then, as the electrophotographic photosensitive member rotates, a fixed amount of charged particles are applied to the charging roller.

In this evaluation apparatus, the charging roller is rotated with a speed difference with respect to the electrophotographic photosensitive member. The electrophotographic photosensitive member of the present invention has a small-diameter drum shape having a diameter of less than 30 mm and rotates at a constant peripheral speed of 110 mm / s.

This evaluation apparatus was modified according to the diameter of the cylindrical support of the electrophotographic photosensitive member in the examples. First,
Charged particles are applied to the surface of the charging roller by a regulating blade. Then, it reaches the contact portion between the charging roller and the electrophotographic photosensitive member. The charging roller was driven at 150 rpm so that the roller surface moved in the opposite direction to the electrophotographic photosensitive member at the same speed, and a DC voltage of -620 V was applied to the roller core metal. As a result, the surface of the electrophotographic photosensitive member is charged to a potential equal to the applied voltage. The charging in the evaluation apparatus is carried out by injecting charging by the charged particles existing in the contact portion between the charging roller and the electrophotographic photosensitive member slidingly rubbing the surface of the electrophotographic photosensitive member without a gap.

<Evaluation device 2> A printer (Laserjet 4000) manufactured by Hewlett-Packard Co. was modified according to the diameter of the cylindrical support of the electrophotographic photosensitive member in the examples. The electrophotographic process methods such as charging, development, transfer, and cleaning were left unchanged. 1 is a configuration of the device of the first embodiment.

The obtained electrophotographic photosensitive member was mounted on the evaluation apparatus 1 and subjected to high temperature and high humidity (30 ° C./80% RH) for 10 hours.
000 sheets of continuous images were output. The output images were all of high quality. After the output, the surface of the electrophotographic photosensitive member was observed with a microscope, and no scratches or the like were found.

The electrophotographic photosensitive member thus obtained was mounted on the evaluation device 2 and continuous image output was performed on 10,000 sheets, but no squeaking occurred.

The results are shown in Table 4.

Example 2 An electrophotographic photosensitive member was prepared in the same manner as in Example 1, except that the protective layer for the electrophotographic photosensitive member was prepared as follows and the cylindrical support had an outer diameter of 24 mm. The body was made.

As a coating liquid for the protective layer, 82 parts of ethanol and the above compound example No. 21 parts of the charge transport material having the structure shown by 8 and a resin component of a resol type phenol resin (trade name: PR-53123, nonvolatile content 45%,
Sumitomo Dures Co., Ltd., synthesized using a metal-based catalyst. Was used as a non-volatile component to dissolve 67 parts, and the mixture was stirred for 4 hours to obtain a coating liquid for protective layer. Place this on the charge transport layer
Drying with hot air at a temperature of 45 ° C. for 1 hour gave an electrophotographic photoreceptor having a protective layer.

When the We% of the obtained electrophotographic photosensitive member was measured, it was 50.7 [%]. Again, │α
₁₋ α ₂ | was 5.6 × 10 ⁻⁵ [° C. ⁻¹ ].

The electrophotographic photosensitive member thus obtained was mounted on the evaluation apparatus 1 and was subjected to 10 hours under an environment of high temperature and high humidity (30 ° C./80% RH).
000 sheets of continuous images were output. In this electrophotographic photosensitive member, although partial electrification was not possible and fogging occurred, when continuous output was tried, no scratch was found in the output image.

The electrophotographic photosensitive member thus obtained was attached to the evaluation device 2 and continuous image output of 10,000 sheets was performed, but no squeaking occurred.

The results are shown in Table 4.

Example 3 Except that the phenol resin synthesized by using the amine catalyst (amine compound) used in Example 1 was replaced by the phenol resin synthesized by using the metal catalyst. An electrophotographic photosensitive member was produced in exactly the same manner as in Example 1.

When the We% of the obtained electrophotographic photosensitive member was measured, it was 52.7 [%]. Further, the difference between the coefficient of thermal expansion measured from the protective layer of the obtained electrophotographic photosensitive member and the coefficient of thermal expansion after removing the protective layer is 7.2 × 10 ⁻⁶ [° C.
⁻¹ ].

The electrophotographic photosensitive member thus obtained was attached to the evaluation apparatus 1 and was subjected to 10 times under an environment of high temperature and high humidity (30 ° C./80% RH).
000 sheets of continuous images were output. The output images were all of high quality. After the output, the surface of the electrophotographic photosensitive member was observed with a microscope, and no scratches or the like were found.

The electrophotographic photosensitive member thus obtained was attached to the evaluation apparatus 2 and continuous image output of 10,000 sheets was performed, but no squeaking occurred.

The results are shown in Table 4.

(Example 4) The resol-type phenol resin used for the protective layer in Example 1 was prepared by using BKS-316 (manufactured by Showa Highpolymer Co., Ltd., an amine-based catalyst (amine compound) other than ammonia. Was synthesized in the same manner as above), but an electrophotographic photosensitive member was produced in exactly the same manner.

When the We% of the obtained electrophotographic photosensitive member was measured, it was 30.2 [%]. The difference between the coefficient of thermal expansion measured on the protective layer of the obtained electrophotographic photosensitive member and the coefficient of thermal expansion after removing the protective layer is 8.3 × 10 ⁻⁷ [° C.
⁻¹ ].

The obtained electrophotographic photosensitive member was mounted on the evaluation apparatus 1 and subjected to high temperature and high humidity (30 ° C./80% RH) environment for 10 minutes.
000 sheets of continuous images were output. The output images were all of high quality. However, when the surface of the electrophotographic photosensitive member was observed with a microscope after the output, some scratches that did not appear on the image were found.

The electrophotographic photosensitive member thus obtained was mounted on the evaluation device 2 and continuous image output of 10,000 sheets was performed, but no squeaking occurred.

The results are shown in Table 4.

(Comparative Example 1) In Example 1, the same procedure was performed up to the charge transport layer, and the phenol resin used in the protective layer was an acrylic monomer 20 having a structure represented by the following formula.
An electrophotographic photosensitive member was prepared in exactly the same manner except that 3 parts of 2-methylthioxanthone was added in place of parts to prepare a coating solution.

[0244]

[Outside 34]

When the We% of the obtained electrophotographic photosensitive member was measured, it was 28.9 [%]. Further, the difference between the coefficient of thermal expansion measured on the protective layer of the obtained electrophotographic photosensitive member and the coefficient of thermal expansion after removing the protective layer is 5.2 × 10 ⁻⁶ [° C.
⁻¹ ].

The obtained electrophotographic photosensitive member was mounted on the evaluation apparatus 1 and subjected to high temperature and high humidity (30 ° C./80% RH) environment for 10 minutes.
000 sheets of continuous images were output. Image defects appeared in the output image. When the surface of the electrophotographic photosensitive member after the output was observed with a microscope, deep scratches were found at the same place where the image defect occurred.

Further, when the obtained electrophotographic photosensitive member was mounted on the evaluation device 2 and 10,000 images were continuously output, no squeaking occurred, but the output image was the same as in the case of the evaluation device 1. Has an image defect. When the surface of the electrophotographic photosensitive member after the output was observed with a microscope, deep scratches were found at the same place where the image defect occurred.

The results are shown in Table 4.

Example 5 The phenol resin used in Example 1 was replaced with a melamine resin (trade name: Cymel 701,
An electrophotographic photosensitive member was produced in exactly the same manner except that 20 parts of Mitsui Cytec Co., Ltd. was used.

When the We% of the obtained electrophotographic photosensitive member was measured, it was 59.6 [%]. Further, the difference between the coefficient of thermal expansion measured from the protective layer of the obtained electrophotographic photosensitive member and the coefficient of thermal expansion after removing the protective layer is 6.4 × 10 ⁻⁷ [° C.
⁻¹ ].

The obtained electrophotographic photosensitive member was mounted on the evaluation apparatus 1 and subjected to high temperature and high humidity (30 ° C./80% RH) for 10 days.
000 sheets of continuous images were output. The output images were all of high quality, but when the surface of the electrophotographic photosensitive member after output was observed with a microscope, some filming was observed.

The electrophotographic photosensitive member thus obtained was mounted on the evaluation apparatus 2 and continuous image output of 10,000 sheets was carried out. However, although similar image defects were found, no squeaking occurred.

The results are shown in Table 4.

(Comparative Example 2) An electrophotographic photosensitive member was produced in exactly the same manner except that 20 parts of the melamine resin used in Example 4 was replaced with 50 parts.

When the We% of the obtained electrophotographic photosensitive member was measured, it was 60.8 [%]. The difference between the coefficient of thermal expansion measured on the protective layer of the obtained electrophotographic photosensitive member and the coefficient of thermal expansion after removing the protective layer is 5.7 × 10 ⁻⁶ [° C.
⁻¹ ].

The obtained electrophotographic photosensitive member was mounted on the evaluation apparatus 1 and subjected to high temperature and high humidity (30 ° C./80% RH) for 10 hours.
000 sheets of continuous images were output. Image defects appeared in the output image. When the surface of the electrophotographic photosensitive member after output was observed with a microscope, filming was observed.
It was determined that this caused an image defect.

Further, when the obtained electrophotographic photosensitive member was mounted on the evaluation device 2 and 10,000 images were continuously output, no squeaking occurred, but the output image was the same as in the case of the evaluation device 1. Has an image defect. When the surface of the electrophotographic photosensitive member after output was observed with a microscope, filming was observed.

The results are shown in Table 4.

Example 6 The phenol resin used in Example 1 was replaced with Epicoat # 81 manufactured by Yuka Shell Co., Ltd.
An electrophotographic photosensitive member was produced in exactly the same manner except that 30 parts of an epoxy resin in which 5 and Epomate B002 were mixed at a mass ratio of 2: 1 was used.

The We% of the obtained electrophotographic photosensitive member was measured and found to be 46.7 [%]. Further, the difference between the coefficient of thermal expansion measured on the protective layer of the obtained electrophotographic photosensitive member and the coefficient of thermal expansion after removing the protective layer is 5.2 × 10 ⁻⁷ [° C.
⁻¹ ].

The obtained electrophotographic photosensitive member was mounted on the evaluation apparatus 1 and subjected to high temperature and high humidity (30 ° C./80% RH) for 10 hours.
000 sheets of continuous images were output. The output image was of high quality. When the surface of the electrophotographic photosensitive member after output was observed with a microscope, no scratches or filming was observed.

The electrophotographic photosensitive member thus obtained was attached to the evaluation device 2 and continuous image output of 10,000 sheets was carried out. Although some "squeaking" occurred, it was not a problematic level.
It was judged that there was no problem in practical use.

The results are shown in Table 4.

(Comparative Example 3) The phenol resin used in Example 1 was replaced with Epicoat # 81 manufactured by Yuka Shell Co., Ltd.
An electrophotographic photosensitive member was produced in exactly the same manner except that 90 parts of an epoxy resin in which 5 and Epomate B002 were mixed at a mass ratio of 2: 1 was replaced.

When the We% of the obtained electrophotographic photosensitive member was measured, it was 52.8 [%]. Further, the difference between the coefficient of thermal expansion measured from the protective layer of the obtained electrophotographic photosensitive member and the coefficient of thermal expansion after removing the protective layer is 4.9 × 10 ⁻⁷ [° C.
⁻¹ ].

The obtained electrophotographic photosensitive member was mounted on the evaluation apparatus 1 and was subjected to 10 times under the environment of high temperature and high humidity (30 ° C./80% RH).
000 sheets of continuous images were output. The output image was of high quality. When the surface of the electrophotographic photosensitive member after output was observed with a microscope, no scratches or filming was observed.

Further, when the obtained electrophotographic photosensitive member was mounted on the evaluation apparatus 2 and 10,000 images were continuously output, similarly high-quality images could be output, but each time the electrophotographic photosensitive member was rotated. "Squeaking" occurred.

The results are shown in Table 4.

(Example 7) The charge transporting material used in the protective layer in Example 2 was the above compound example No. An electrophotographic photosensitive member was produced in exactly the same manner as in Example 2 except that the compound having the structure shown by 31 was used.

The We% of the obtained electrophotographic photosensitive member was measured and found to be 49.2 [%]. Further, the difference between the coefficient of thermal expansion measured on the protective layer of the obtained electrophotographic photosensitive member and the coefficient of thermal expansion after removing the protective layer is 9.7 × 10 ⁻⁵ [° C.
⁻¹ ].

The obtained electrophotographic photosensitive member was mounted on the evaluation apparatus 1 and subjected to high temperature and high humidity (30 ° C./80% RH) for 10 hours.
When 000 sheets of continuous images were output, the output image was of high quality. When the surface of the electrophotographic photosensitive member after output was observed with a microscope, the surface layer at the end portion other than the image area was about to peel off.

Further, when the obtained electrophotographic photosensitive member was mounted on the evaluation apparatus 2 and 10000 sheets of continuous images were output, similarly high-quality images could be output and there was no noise.

The results are shown in Table 4.

(Comparative Example 4) An electrophotographic photosensitive member was prepared in exactly the same manner as in Example 6 except that the charge transporting material used in Example 6 was replaced with the compound having the structure represented by the formula below.

[0275]

[Outside 35]

The We% of the obtained electrophotographic photosensitive member was measured and found to be 37.2 [%]. Further, the difference between the coefficient of thermal expansion measured on the protective layer of the obtained electrophotographic photosensitive member and the coefficient of thermal expansion after removing the protective layer is 1.2 × 10 ⁻⁴ [° C.
⁻¹ ].

The electrophotographic photosensitive member thus obtained was mounted on the evaluation apparatus 1 and subjected to high temperature and high humidity (30 ° C./80% RH) environment for 10 minutes.
000 sheets of continuous images were output. The output image had an image defect. When the surface of the electrophotographic photosensitive member after output was observed with a microscope, the surface layer was peeled off, and many scratches were observed on the surface after peeling.

Further, when the obtained electrophotographic photosensitive member was mounted on the evaluation device 2 and 10000 sheets of continuous images were output, similarly high-quality images could be output and there was no noise such as "squeaking".

The results are shown in Table 4.

Example 8 Except that the protective layer of the electrophotographic photosensitive member formed in Example 1 was formed as follows.
A protective layer was formed on the charge transport layer in the same manner as in Example 1 to prepare an electrophotographic photosensitive member and evaluated.

For the protective layer, 30 parts of antimony-doped tin oxide ultrafine particles surface-treated with a compound having a structure represented by the following formula (treatment amount: 7%),

[Outside 36]

Antimony-doped tin oxide fine particles 2 (20%) surface-treated with methyl hydrogen silicone oil (trade name: KF99, manufactured by Shin-Etsu Silicone Co., Ltd.)
0 part was added, and 150 parts of ethanol were dispersed in a sand mill for 66 hours (average particle size 0.03μ).
m). Furthermore, 20 parts of polytetrafluoroethylene fine particles (average particle diameter 0.18 μm) were added, and the dispersion was further performed for 2 hours.

After that, 30 parts of a resol type phenol resin (trade name: PL-4852; manufactured by Gunei Chemical Industry Co., Ltd., synthesized by using an amine catalyst (amine compound)) was dissolved in 30 parts. Then, it was used as a preparation liquid. Then, a film is formed on the charge transport layer by the dip coating method, and the film is formed at 145 ° C.
After drying with hot air for 1 hour, an electrophotographic photosensitive member having a protective layer with a film thickness of 2 μm was obtained. At this time, the dispersion state of the protective layer coating material was good, and the formed protective layer was a uniform and uniform film.

We% of the electrophotographic photosensitive member thus obtained and | α ₁
−α ₂ | was measured.

Further, the obtained electrophotographic photosensitive member was mounted on the evaluation apparatus 1 and continuous image output of 10,000 sheets was performed in an environment of high temperature and high humidity (30 ° C./80% RH). The output images were all of high quality.

After the output, the surface of the electrophotographic photosensitive member was observed with a microscope, and no scratches or the like were found.
Further, as compared with Example 1, the color reproducibility of 16 gradations was particularly excellent.

The electrophotographic photosensitive member thus obtained was mounted on the evaluation device 2 and continuous image output of 10,000 sheets was performed, but no squeaking occurred.

The results are shown in Table 4.

(Examples 9 to 14) As Example 1 except that the protective layer of the electrophotographic photosensitive member was formed as follows and the outer diameter of the cylindrical support was 24 mm. An electrophotographic photoreceptor was prepared in the same manner.

As a coating liquid for the protective layer, 82 parts of ethanol and, in the order of Examples 9 to 14, Compound Example No. 1
2, No. 25, no. 31, No. 44, No. Four
9, No. 56 parts by 21 parts, and 30 parts by part as a resin component, a resol type phenol resin (trade name: PL-4852, manufactured by Gunei Chemical Co., Ltd., synthesized by using an amine-based catalyst (amine compound)) as a non-volatile component. After dissolution and stirring for 4 hours, 10 parts of polytetrafluoroethylene fine particles (average particle size 0.18 μm) were added and dispersed for 2 hours to obtain a protective layer coating liquid. Thus, a film was formed on the charge transport layer by a dip coating method and dried with hot air at a temperature of 145 ° C. for 1 hour to obtain an electrophotographic photosensitive member having a protective layer with a film thickness of 2 μm.

We% and | α _{1 of the} obtained electrophotographic photosensitive member
−α ₂ | was measured.

Further, the obtained electrophotographic photosensitive member was mounted on the evaluation apparatus 1 and continuous image output of 10,000 sheets was performed in an environment of high temperature and high humidity (30 ° C./80% RH). All of the output images were images that were slightly fogged due to insufficient partial charge, but no scratches were found on the images even after continuous output.

Further, after the output, when the surface of the electrophotographic photosensitive member was observed in detail with a microscope, no scratches were found at all.

The electrophotographic photosensitive member thus obtained was mounted in the evaluation apparatus 2 and continuous image output of 10,000 sheets was performed, but no squeaking occurred. Furthermore, the reproducibility of fine lines was very excellent even when compared with Example 2.

The results are shown in Table 4.

[0296]

[Table 1]

Reference Examples 1 to 4 Electrophotographic photosensitive members were produced on a support having an outer diameter of 30 mm in the same manner as Comparative Examples 1 to 4.
The same evaluation was performed, but no problems such as peeling, scratching, squealing, and fusion that occurred remarkably on the electrophotographic photosensitive member having a reduced diameter did not occur.

[0298]

According to the present invention, even if a photosensitive layer and a protective layer are formed on a cylindrical support having a small diameter, the protective layer is not peeled or fused, and noise such as squeal is generated. It is possible to provide an electrophotographic photosensitive member having a protective layer which is not generated and has excellent scratch resistance and abrasion resistance, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus.

[Brief description of drawings]

FIG. 1 is a diagram showing a layer structure of an electrophotographic photosensitive member of the present invention.

FIG. 2 is a diagram showing a schematic configuration example of Embodiment 1 which is an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.

FIG. 3 is a diagram showing a schematic configuration example of a second embodiment which is an electrophotographic apparatus provided with a process cartridge having a charged particle supply unit on the electrophotographic photosensitive member of the present invention.

[Fig. 4] Depth of indentation of 3 μm measured by Fisher hardness tester
It is a measurement chart of.

[Explanation of symbols]

1 protective layer 2 Charge transport layer 3 Charge generation layer 4 support 5 Middle class 6 Conductive layer 11 Electrophotographic photoreceptor 12 axes 13 charging means 14 exposure light 15 Developing means 16 Transfer means 17 Transfer material 18 Fixing means 19 Cleaning means 20 Pre-exposure light 21 Process cartridge 22 Guide means 31 Electrophotographic photoreceptor 32 charging roller 32a core metal 32b Middle resistance layer 33 charged particles 34 Regulation blade 35 Laser beam scanner 36 developing means (developing device) 37 transfer means (transfer roller) 38 fixing means (fixing roller) 40 rails Wt total work (nJ) A-B-D-A We Work of elastic deformation (nJ) C-B-D-C Wr Work of plastic deformation (nJ) ABCA

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor ▲ Yoshi ▼ Kimihiro Mura             Kyano, 3-30-2 Shimomaruko, Ota-ku, Tokyo             Within the corporation (72) Inventor Tatsuya Ikezue             Kyano, 3-30-2 Shimomaruko, Ota-ku, Tokyo             Within the corporation (72) Inventor Koichi Nakata             Kyano, 3-30-2 Shimomaruko, Ota-ku, Tokyo             Within the corporation F-term (reference) 2H068 AA03 AA13 BB27 FA27 FC01                 2H200 FA07 GA16 GA17 GA23 GA34                       GA44 GB25 GB37 HA03 HA21                       HB12 HB17 HB22 HB46 HB47                       HB48 MB01 MC01 MC15 NA02

Claims (27)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer and a protective layer on a cylindrical support in this order, and the outer diameter of the cylindrical support being less than 30 mm. The heat measured from above the protective layer. and expansion (alpha _1), the difference between the thermal expansion coefficient was measured after removing the protective layer _{(α 2) (| α 1} -α 2 |) is, 5.0 ×
^Greater than 10 ⁻⁷ [° C. ⁻¹ ] and 1.0 × 10 ⁻⁴ [° C.
⁻¹ ] and the elastic deformation rate (We%) measured from above the protective layer is more than 30% and less than 60%, the electrophotographic photoreceptor. 2. The electrophotographic photosensitive member according to claim 1, wherein the protective layer contains a binder resin and at least one of conductive particles and a charge transport substance. 3. The electrophotographic photosensitive member according to claim 2, wherein the binder resin is a curable resin. 4. The electrophotographic photosensitive member according to claim 3, wherein the curable resin is at least one selected from the group consisting of a phenol resin, an epoxy resin and a siloxane resin. 5. The electrophotographic photosensitive member according to claim 4, wherein at least one of the curable resins is a phenol resin, and the phenol resin is a resol type phenol resin. 6. The electrophotographic photosensitive material according to claim 5, wherein the resol-type phenol resin is a resin synthesized by using at least one selected from the group consisting of alkali metals, alkaline earth metals and amine compounds. body. 7. The electrophotographic photosensitive member according to claim 6, wherein the resol-type phenol resin is a resin synthesized by using an amine compound. 8. The electrophotographic photosensitive member according to claim 4, wherein at least one of the curable resins is a phenol resin, and the phenol resin is a thermosetting phenol resin. 9. The electrophotographic photosensitive member according to claim 1, wherein the protective layer contains at least conductive particles, and the conductive particles are metal particles or metal oxide particles. 10. The electrophotographic photoreceptor according to claim 1, wherein the protective layer contains at least one of a fluorine atom-containing compound and a siloxane compound. 11. The protective layer contains at least a fluorine atom-containing compound, and the fluorine atom-containing compound is selected from the group consisting of a fluorine-containing silane coupling agent, a fluorine-modified silicone oil and a fluorine-based surfactant. The electrophotographic photosensitive member according to claim 10, which is at least one compound. 12. The protective layer contains at least a siloxane compound, and the siloxane compound has the following formula (1):
The electrophotographic photosensitive member according to claim 10, which is a siloxane compound having a structure represented by: [Outer 1] (In the formula (1), A ^{11 to} A ¹⁸ are each independently a hydrogen atom or a methyl group. However, the total number of A (a))
The ratio (b / a) of the total number (b) of the hydrogen atoms with respect to is 0.001 or more and 0.5 or less. n ¹¹ is an integer of 0 or more. ) 13. The electrophotographic photosensitive member according to claim 1, wherein the protective layer contains lubricating particles. 14. The electrophotographic photosensitive member according to claim 13, wherein the lubricating particles are at least one kind of particles selected from the group consisting of fluorine atom-containing resin particles, silicone resin particles, silica particles and alumina particles. . 15. The electrophotographic photosensitive member according to claim 1, wherein the protective layer contains at least a charge transport substance, and the charge transport substance has a hydroxyl group in the molecule. 16. The electrophotographic photoreceptor according to claim 15, wherein the charge transport material has at least one of a hydroxyalkyl group and a hydroxyalkoxyl group in the molecule. 17. The charge transport material having at least one of a hydroxyalkyl group and a hydroxyalkoxyl group in the molecule has a structure represented by one formula selected from the group consisting of the following formulas (2) to (4). Claim 1 having
6. The electrophotographic photosensitive member according to item 6. [Outside 2] (In formula (2), R <^21> , R <^22> and R < ²³ > each independently represent a divalent hydrocarbon group having 1 to 8 carbon atoms and which may be branched. , Each independently a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted aromatic heterocyclic group It may have as a group a,
b, d, m and n each independently represent 0 or 1. ) [Outside 3] (In formula (3), R ³¹ , R ^32, and R ³³ each independently represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched. The benzene rings of δ and ε are, respectively, Independently, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted aromatic heterocyclic group as a substituent May have e, f
And g each independently represent 0 or 1. p,
q and r are each independently 0 or 1,
Not all can be 0 at the same time. Z ³¹ and Z ³²
Are each independently a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted aromatic heterocyclic group. They may be shown or jointly formed into a ring. ) [Outer 4] (In the formula (4), R ⁴¹ , R ⁴² , R ^43, and R ^43
44 each independently represents a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched. The benzene rings of ζ, η, θ and ι are each independently a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted Alternatively, it may have an unsubstituted aromatic heterocyclic group as a substituent. h, i, j, k, s, t and u each independently represent 0 or 1. Z ⁴¹ and Z ⁴²
Are each independently a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted aromatic heterocyclic group. They may be shown or jointly formed into a ring. ) 18. The electrophotographic photosensitive member according to claim 1, wherein the protective layer contains at least a charge-transporting substance, and the charge-transporting substance has a hydroxyphenyl group in the molecule. 19. The charge transport material having a hydroxyphenyl group in the molecule has a structure represented by one formula selected from the group consisting of the following formulas (5) to (7). Electrophotographic photoreceptor. [Outside 5] (In the formula (5), R ⁵¹ represents a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched. R ⁵² represents a hydrogen atom,
A substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted phenyl group is shown. Ar ⁵¹ and Ar ⁵² are each independently a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted aromatic heterocycle. Indicates a group. Ar
⁵³ represents a substituted or unsubstituted divalent aromatic hydrocarbon ring group or a substituted or unsubstituted divalent aromatic heterocyclic group. v and w each independently represent 0 or 1. However, when v = 0, w = 0. The benzene rings of κ and λ are each independently a halogen atom,
It may have a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted aromatic heterocyclic group as a substituent. ) [Outside 6] (In the formula (6), R ⁶¹ represents a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched. Ar ⁶¹ and Ar
⁶² each independently represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted aromatic heterocyclic group. x represents 0 or 1. The μ and ν benzene rings are each independently a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted It may have an aromatic heterocyclic group as a substituent, or the benzene rings of μ and ν may jointly form a ring via a substituent. ) [Outer 7] (In the formula (7), R ⁷¹ and R ⁷² each independently represent a divalent hydrocarbon group having 1 to 8 carbon atoms which may be branched. Ar ⁷¹ is a substituted or unsubstituted alkyl group, It represents a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aromatic hydrocarbon ring group, or a substituted or unsubstituted aromatic heterocyclic group, and y and z each independently represent 0 or 1. The benzene rings of ξ, π, ρ and σ are each independently a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxyl group,
It may have a substituted or unsubstituted aromatic hydrocarbon ring group or a substituted or unsubstituted aromatic heterocyclic group as a substituent, a benzene ring of ξ and π, and a benzene ring of ρ and σ. May independently form a ring jointly via a substituent. ) 20. A contact charging means having an electrophotographic photoreceptor, a charging means, an exposing means, a developing means and a transferring means, wherein the charging means is a contact charging means having a charging member arranged in contact with the electrophotographic photoreceptor. The electrophotographic photoreceptor according to any one of claims 1 to 19, which is an electrophotographic photoreceptor for an electrophotographic apparatus, wherein the charging member is a contact charging member that charges only the DC voltage to charge the electrophotographic photoreceptor. 21. The contact charging member is composed of charged particles for contacting with an electrophotographic photosensitive member, and a charged particle carrier having a conductive and elastic surface for supporting the charged particles. A charged particle having a particle size of 10
1 to 10 μm, wherein the contact charging means is an injection charging means for charging the electrophotographic photosensitive member by directly injecting electric charges to the surface of the electrophotographic photosensitive member by the charged particles. 20. The electrophotographic photosensitive member according to any one of 20. 22. A process which integrally supports an electrophotographic photosensitive member and at least one unit selected from the group consisting of a charging unit, a developing unit, a transfer unit and a cleaning unit, and which is detachable from the main body of the electrophotographic apparatus. A process cartridge, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 1 to 19. 23. The electrophotographic photosensitive member and the charging unit are integrally supported, and the charging unit is a contact charging unit having a charging member disposed in contact with the electrophotographic photosensitive member, and the charging member is a direct current. The process cartridge according to claim 22, which is a contact charging member that charges only the voltage to charge the electrophotographic photosensitive member. 24. The contact charging member is composed of charged particles for contacting an electrophotographic photosensitive member, and a charged particle carrier having a conductive and elastic surface for supporting the charged particles. A charged particle having a particle size of 10
23 nm to 10 μm, and the contact charging means is an injection charging means for charging the electrophotographic photosensitive member by directly injecting electric charges to the surface of the electrophotographic photosensitive member by the charged particles.
Or the process cartridge described in 23. 25. An electrophotographic apparatus having an electrophotographic photoreceptor, a charging means, an exposing means, a developing means and a transferring means, wherein the electrophotographic photoreceptor is the electrophotographic photoreceptor according to any one of claims 1 to 19. An electrophotographic apparatus characterized in that 26. The contact charging means having a charging member arranged in contact with the electrophotographic photosensitive member,
The electrophotographic apparatus according to claim 25, wherein the charging member is a contact charging member that charges only the DC voltage to charge the electrophotographic photosensitive member. 27. The contact charging member is composed of charged particles for contacting an electrophotographic photosensitive member, and a charged particle carrier having a conductive and elastic surface for supporting the charged particles. A charged particle having a particle size of 10
26 nm to 10 μm, and said contact charging means is an injection charging means for directly charging the surface of the electrophotographic photosensitive member with the charged particles to charge the electrophotographic photosensitive member.
Or the electrophotographic apparatus according to item 26.