JP2000010320A - Electrophotographic photoreceptor, process cartridge and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide excellent wear resistance, enhance the uniformity of potential by endurance, make toner fusion difficult to occur, and supply a satisfactory image by constituting the surface layer of an electrophotographic photoreceptor so that the universal hardness value (Hu) is a specified value in a surface film hardness test under a specified environment, and the plastic deformation rate of the surface layer by an indenter satisfies a specified condition. SOLUTION: The surface of an electrophotographic photoreceptor having a conductive support and an organic photosensitive layer is set so that Hu is 230 N/mm2<=Hu<=700 N/mm2 in a surface film hardness test under the environment of 25 deg.C and humidity 50%, and the plastic deformation rate of the surface layer by an indenter used for the surface film hardness test satisfies the expression. The mechanical strength is insufficient when Hu is less than 230 N/mm2, the organic polymer film exceeding 700 N/mm2 is practically difficult since the handling in manufacture is remarkably deteriorated, and the mechanical strength and the limitation in manufacture can be cleared within the range of 230 N/mm2<=Hu<=700 N/mm2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic photoreceptor,
More specifically, the present invention relates to an electrophotographic photosensitive member having a surface layer having a specific hardness, a process cartridge having an electrophotographic photosensitive member, and an electrophotographic apparatus.

[0002]

2. Description of the Related Art An electrophotographic method is disclosed in U.S. Pat.
As shown in JP-A-91, an electric resistance changes according to the amount of irradiation received during image exposure, and in a dark place, a photoconductive material composed of a support coated with an insulating material is used. The basic characteristics required of an electrophotographic photoreceptor using this photoconductive material include (i) being able to be charged to an appropriate potential in a dark place, (ii) being less likely to dissipate in a dark place, (Iii) Quickly dissipating the charge by light irradiation.

[0003] Conventionally, selenium,
Inorganic photoreceptors having a photosensitive layer mainly containing an inorganic photoconductive compound such as zinc oxide and cadmium sulfide have been widely used. However, these satisfies the conditions (i) to (iii), but are not necessarily satisfactory in thermal stability, moisture resistance, durability, productivity, and the like.

In order to overcome the disadvantages of inorganic photoreceptors, electrophotographic photoreceptors containing various organic photoconductive compounds as main components have been actively developed in recent years. For example, US Pat.
Japanese Patent No. 7851 discloses a photoreceptor having a charge transport layer containing triallyl pyrazoline, and US Pat. No. 3,871,880 discloses a charge generating layer comprising a derivative of perylene pigment and a charge comprising a condensate of 3-propylene and formaldehyde. A photoreceptor comprising a transport layer is known.

Electrophotographic photoreceptors using these organic photoconductive compounds are used as function-separated type photoreceptors in which a charge transport layer and a charge generation layer are laminated in order to satisfy both electrical and mechanical properties. Often done. On the other hand, as a matter of course, the electrophotographic photoreceptor is required to have sensitivity, electrical characteristics, and optical characteristics according to the electrophotographic process applied.

In particular, in the case of an electrophotographic photoreceptor that is used repeatedly, the surface of the electrophotographic photoreceptor is directly subjected to an electrical or mechanical external force such as corona or direct charging, image exposure, toner development, transfer process, surface cleaning and the like. Therefore, durability for them is also required. More specifically, it is resistant to chemical deterioration due to ozone and nitrogen oxides during charging, mechanical deterioration in which the surface is worn or scratched due to discharge during charging and rubbing of a cleaning member, and electrical deterioration. Sex is required.

[0007] The mechanical deterioration is particularly inferior to the mechanical deterioration of the organic photoreceptor which often has a material softness unlike the inorganic photoreceptor, and the improvement of the durability is particularly desired. Further, the surface roughness of the photoreceptor increases due to mechanical deterioration, and a difference in film thickness occurs when viewed microscopically. This causes a change in the photoreceptor capacity in a very small range, which also affects the uniformity of sensitivity.

Further, when the roughness of the surface becomes large and the unevenness is in a certain range, the image exposure light may be irregularly reflected on the surface. This is particularly true when the light source of the image exposure light is a laser beam, and depending on how the surface of the photoconductor is roughened when a practical image is printed, if the beam diameter is 60 μm or less, the surface of the photoconductor may be roughened. This makes it susceptible to diffuse reflection. In addition, paper powder, developer, and the like adhere to the concave and convex portions due to the surface roughness (hereinafter, referred to as toner fusion), which causes a problem of image deterioration. As described above, an increase in the mechanical strength of the surface of the organic photoreceptor has been desired more than before.

By the way, hardness is one measure for measuring the degree of mechanical deterioration of a certain material. This definition is regarded as stress from the material due to indentation of the indenter. Therefore, using this hardness as a physical parameter for knowing the strength of the surface film, attempts have been made to quantify the mechanical strength quantitatively. As examples thereof, a scratch hardness test, a pencil hardness test, a Vickers hardness test, and the like, which have been widely used, are widely known.

However, each of the measuring means has advantages and disadvantages when measuring the strength of an elastic film such as an organic substance. For example, in the Vickers hardness measurement, the length of an indentation on a film is measured to determine the hardness, and is not suitable for an elastically deformable material such as an organic material. As described above, it is desired that the hardness of the organic substance with respect to the film can be evaluated by a value obtained by adding the plastic deformation and the elastic deformation of the film by the indenter.

On the other hand, a polycarbonate resin having a skeleton of bisphenol A, which has been conventionally used for the surface layer, has attracted attention, but not all of the above-mentioned problems can be solved. Recently, attempts have been made to solve the above problems by copolymerizing with a polycarbonate Z resin having a bulky cyclohexylene group as a polymer structural unit, bisphenol Z, bisphenol C, or the like.

[0012]

SUMMARY OF THE INVENTION The object of the present invention is to
An object of the present invention is to provide an electrophotographic photosensitive member, a process cartridge, and an electrophotographic apparatus which are excellent in abrasion resistance, increase the uniformity of potential due to durability, make it difficult to fuse toner, and can supply a good image.

[0013]

According to the present invention, in an electrophotographic photosensitive member having a conductive support and an organic photosensitive layer, the surface layer of the electrophotographic photosensitive member is subjected to surface film hardness at 25 ° C. and 50% humidity. The test was performed and the resulting universal hardness value (Hu) was 230 N / mm ² ≦ Hu.
≦ 700 N / mm ² , and the plastic deformation rate of the surface layer satisfies the following formula (1) by the indenter used for the surface film hardness, and an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus are provided. Is done.

[0014]

(Equation 5)

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The surface coating hardness tester used in the present invention is a method in which an indenter is pushed into the surface of a sample as in a conventional micro Vickers method, and the residual dent after unloading is measured with a microscope to determine the hardness. Rather, it is a measurement method in which a load is continuously applied to the indenter, the indentation depth under the load is directly read, and the hardness is continuously obtained. Therefore, it is possible to measure even an elastic film such as an organic thin film.

The indenter used in the surface film hardness meter includes a Vickers diamond indenter, a Knoop indenter, a Berkovich indenter, a ball indenter and the like. Use them properly depending on the measurement conditions. For example, when measuring a highly viscous organic polymer film, a ball indenter is said to be suitable.
The universal hardness value (Hu) is defined by the following equation (2) by measuring the indentation depth of a Vickers diamond indenter under a test load.

[0017]

(Equation 6)

Further, by reducing the load of the indenter, the elastic energy (plastic energy) of the film can be analyzed. The plastic deformation rate (elastic deformation rate) is obtained from the work (energy) performed by the indenter on the film, that is, the change in energy due to the increase and decrease of the load of the indenter on the film. I get it.

In general, there are plastic deformation and elastic deformation in the deformation of an organic polymer film due to external stress, and it is said that the physical properties of the film are characterized by the ratio of each deformation to the total deformation. For example, a material having rigidity such as carbon fiber has a plastic deformation rate close to 100% of the whole, and a rubber-like material such as elastomer has a large elastic deformation ratio.

By the way, as described in the prior art, the performance immediately required for the surface layer of the organic electrophotographic photosensitive member is as follows.
Improvement of durability against mechanical deterioration can be cited. In order to realize this, the film is rigid but brittle as a property of the film, and there is a problem in that it is difficult to use even if the film is too ductile although it is flexible.

After careful study, we focused on the hardness and deformation rate of the electrophotographic photoreceptor surface layer, and determined the universal hardness value (Hu) and plastic deformation rate (elastic deformation rate) obtained using a surface film hardness meter. It has been found that when the value is within a certain range, mechanical deterioration of the photoreceptor surface layer hardly occurs. That is, Hu
Is less than 230 N / mm ² , the current electrophotographic process is insufficient in mechanical strength and 70
0N / mm ² more than the organic polymer film is practically difficult because the handling is remarkably deteriorated in the manufacturing for the organic electrophotographic photosensitive member of current, 230N / mm ²
In the range of ≦ Hu ≦ 700 N / mm ² , the mechanical strength and the restrictions on manufacturing can be cleared.

Further, if the plastic deformation rate of the film is 70% or more, the elasticity of the film is insufficient with respect to the cleaning blade, paper powder or toner. It may cause fusion or damage. On the other hand, if it is 30% or less, the stretchability of the film becomes too large, the adhesion with the cleaning blade increases, the blade is pulled in the photosensitive drum rotation direction, and the blade is repelled by the accumulation of stress at that time,
This causes cleaning failure.

When the indenter used in the surface film hardness test is a Vickers square diamond indenter, the maximum value of the load applied to the indenter is in the range of 5 to 300 mN. This is because if it is less than 5 mN with respect to the surface of the electrophotographic photoreceptor, the accuracy of measurement is reduced due to the influence of irregularities on the surface of the film, and if it exceeds 300 mN, it depends on the thickness of the surface layer. However, this is because the indenter is easily affected by the substrate.

The electrophotographic photoreceptor according to the present invention can have particularly excellent mechanical strength due to the resin forming the surface layer, can eliminate microscopic potential unevenness, and can have a uniform density especially in a halftone image. And a good image without toner fusion or the like can be obtained. Also, in the electrophotographic apparatus according to the present invention, even if the spot diameter of the still image obtained by the exposure means for forming a dot-shaped electrostatic latent image is as small as 60 μm or less, the surface of the electrophotographic photosensitive member Since the surface roughness is small, irregular reflection does not occur, and image unevenness hardly occurs.

As one of the resins used in the present invention,
Specific examples of structural units of the polyarylate resin are shown in Table 1, but are not limited thereto.

[0026]

[Table 1]

The polymer having a constitutional unit represented by the formula (1) used in the present invention is prepared by converting a bisphenol represented by the following formula (4) with a mixture of terephthalic acid chloride / isophthalic acid chloride in the presence of an alkali. It is prepared by mixing in a solvent / water system and performing interfacial polymerization. The ratio between terephthalic acid chloride and isophthalic acid chloride is determined in consideration of the solubility of the polymer, and is not defined. However, care must be taken when the content of any chloride is 30 mol% or less, since the solubility of the synthesized polymer is extremely reduced. Usually, it is preferable to synthesize at a ratio of 1/1.

[0028]

Embedded image

Wherein X is -CR_ThreeR_Four-(However, R_Threeas well as
R_FourAre each independently a hydrogen atom, a trifluoromethyl group,
An alkyl group such as methyl or ethyl having a prime number of 1 to 6, or carbon
Aryl groups such as phenyl and naphthyl represented by Formulas 6 to 12;
1) -C1-C1-C1-C1-C1-C1 which may be substituted
Loalkylene group, α, ω-alkylene having 2 to 10 carbon atoms
Group, single bond, -O-, -S-, -SO-, or -SO_Two
-. Also, R₁And R _TwoAre each independently a hydrogen atom,
Halogen atoms such as urine, bromine and chlorine, which may be substituted
Alkyl groups such as methyl and ethyl, phenyl, naphthyl, etc.
Aryl groups, alkylene groups such as ethylene and propylene
And a and b are each independently an integer of 0 to 4.

In the electrophotographic photoreceptor of the present invention, a polymer composed of the same structural unit represented by the formula (1) or a polymer composed of two or more different structural units represented by the formula (1) May be used. Preferred examples include structural unit examples 1-1, 1-2, and 1-7. In the case of a polymer having the same structural unit, the polymer composed of structural unit example 1-1 is particularly preferable. Preferably, in the case of a copolymer composed of two or more different types of structural units represented by the formula (1), a copolymer composed of the structural unit example 1-1 and the structural unit example 1-2 is particularly preferable.

Further, as a resin group used in the present invention, the following formula (2) or (3)

[0032]

Embedded image

[0033]

Embedded image

In the formula, R ₅ and R ₆ represent hydrogen, an alkyl group such as methyl and ethyl which may be substituted, and a halogen atom such as iodine, bromine and chlorine; x and y each represent an integer of 1 or more; m and n used a phenylene structure having a constitutional unit represented by an integer of 10 or more. Specific examples are shown in Table 2, but are not limited thereto.

[0035]

[Table 2]

In the electrophotographic photoreceptor of the present invention, two or more types of the formulas (2) and (3) may be used even if the polymer has the same structural unit represented by the formula (2) or (3).
May be a copolymer composed of different kinds of structural units.
Preferred examples are structural unit examples 2-1, 2-2, and 2-
6, 2-7, and in the case of a polymer composed of the same structural unit, a polymer composed of the structural unit example 2-1 is particularly preferable, and two or more types of the formulas (2) and (3) are preferable. In the case of a copolymer composed of different kinds of structural units shown in ()), a copolymer composed of structural unit example 2-1 and structural unit example 2-6 is particularly preferable.

Hereinafter, the configuration of the electrophotographic photosensitive member used in the present invention will be described. The electrophotographic photoreceptor in the present invention may be a single layer type in which the photosensitive layer contains a charge transport material and a charge generation material in the same layer, or a laminated type in which a charge transport layer and a charge generation layer are separated. From the standpoint of photographic characteristics, a laminated type is preferred.

The conductive support to be used may be any one having conductivity, such as a metal such as aluminum or stainless steel.
Alternatively, metal, paper, plastic, or the like provided with a conductive layer may be mentioned, and the shape may be a sheet, a cylinder, or the like.

A conductive layer may be provided for the purpose of covering the scratch on the support. This can be formed by dispersing conductive powder such as carbon black and metal particles in a binder resin. The thickness of the conductive layer is preferably from 5 to 40 μm, more preferably from 10 to 30 μm.

An intermediate layer having an adhesive function is provided thereon. Examples of the material of the intermediate layer include polyamide, polyvinyl alcohol, polyethylene oxide, ethyl cellulose, casein, polyurethane, and polyether urethane. These are applied by dissolving in an appropriate solvent. The thickness of the intermediate layer is preferably 0.05 to 5 μm, and 0.3 to 1 μm.
μm is more preferably suitable.

The charge generation layer is formed on the intermediate layer. The charge generation material used in the present invention is selenium-
Tellurium, pyrylium, thiapyrylium dye, phthalocyanine, anthrone, dibenzopyrenequinone, trisazo, cyanine, disazo, monoazo, indigo,
Examples thereof include quinacridone and asymmetric quinocyanine pigments, which are formed by mixing these with a binder resin, applying a coating material dispersed in a solvent, and drying.

In the case of the function-separated type, the charge generation layer is formed by a method using a homogenizer, an ultrasonic dispersion, a ball mill, a vibration ball mill, a sand mill, an adrider, a roll mill, a liquid collision type high-speed disperser, etc. Well dispersed.

Examples of the binder resin used herein include polyester resin, polyacryl resin, polyvinyl carbazole resin, phenoxy resin, polycarbonate resin, polystyrene resin, polyvinyl acetate resin, polysulfone resin, polyarylate resin, vinyl chloride, polyvinyl benzal resin, Bolibutyral resin or the like is mainly used. The ratio between the binder resin and the pigment is preferably 1/10 to 10/1, more preferably 1.5 to 10/1.
/ 1 to 3/1. The dispersion is formed by coating and drying. The thickness of the charge generation layer is preferably 5 μm or less.
01 to 2 μm is more preferable and appropriate.

The charge transport layer is mainly formed by applying a coating material in which a charge transport material and a binder resin of the present invention are dissolved in a solvent and drying the coating material. Examples of the charge transport material used include a triarylamine compound, a hydrazine compound, a stilbene compound, a pyrazoline compound, an oxazole compound, a triallylmethane compound, and a thiazole compound. These are combined with 0.5 to 2 times the amount of the binder resin, applied and dried to form a charge transport layer. The thickness of the charge transport layer is preferably from 5 to 50 μm, more preferably from 15 to 35 μm.

FIG. 1 shows a schematic configuration of an electrophotographic apparatus having a process cartridge having the electrophotographic photosensitive member of the present invention. In FIG. 1, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is driven to rotate around an axis 2 at a predetermined peripheral speed in a direction indicated by an arrow. The photoreceptor 1 receives a uniform charge of a predetermined positive or negative potential on the peripheral surface thereof by the primary charging means 3 during the rotation process, and then receives a charge from an image exposure means (not shown) such as slit exposure or laser beam scanning exposure. It receives image exposure light 4. Thus, an electrostatic latent image is sequentially formed on the peripheral surface of the photoconductor 1.

Of the latent images thus obtained, those formed in the form of dots have recently been applied to digital image forming apparatuses. In this system, it is considered that a sharp latent image can be obtained by narrowing the effective development area in the dot-shaped still image, and the developability of isolated dots with toner is improved.

The formed electrostatic latent image is then transferred to developing means 5
The toner-developed image developed by the toner image is transferred from a paper supply unit (not shown) between the photoconductor 1 and the transfer unit 6 in synchronization with the rotation of the photoconductor 1 and fed to a transfer material 7 fed therefrom. The image is sequentially transferred by the transfer unit 6.

The transfer material 7 which has undergone the image transfer is separated from the photoreceptor surface, introduced into the image fixing means 8 and subjected to image fixing to be printed out of the apparatus as a copy. The surface of the photoreceptor 1 after the image transfer is cleaned and cleaned by removing the untransferred toner by a cleaning unit 9, and further subjected to a charge removal process by a pre-exposure light 10 from a pre-exposure unit (not shown). Used for image formation. When the primary charging unit 3 is a contact charging unit using a charging roller or the like, the pre-exposure is not necessarily required.

In the present invention, a plurality of components such as the above-described electrophotographic photosensitive member 1, primary charging means 3, developing means 5, and cleaning means 9 are integrally connected as a process cartridge. The process cartridge may be configured to be detachable from a main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. For example, at least one of the primary charging unit 3, the developing unit 5, and the cleaning unit 9 is integrally supported together with the photoreceptor 1 to form a cartridge, which can be attached to and detached from the apparatus main body using a guide unit such as a rail 12 of the apparatus main body. Process cartridge 1
It can be 1.

When the electrophotographic apparatus is a copying machine or a printer, the image exposure light 4 is reflected and transmitted from the original, or the original is read by a sensor and converted into a signal. Laser beam scanning,
Light emitted by driving the LED array, driving the liquid crystal shutter array, and the like.

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

[0052]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following is a description of embodiments. In the examples,
"Parts" represents parts by weight.

(Example 1) φ30 mm, length 357.5
mm aluminum cylinder as a support,
A coating composed of the following materials was applied to the support by a dipping method, and thermally cured at 140 ° C. for 30 minutes to form a 15 μm conductive layer.

Conductive pigment: SnO ₂ coated barium sulfate 10 parts Resistance adjusting pigment: titanium oxide 2 parts Binder resin: phenol resin 6 parts Leveling material: silicone oil 0.001 part Solvent: methanol / methoxypropanol 0.2 / 0.8 20 parts

Next, 3 parts of N-methoxymethylated nylon and 3 parts of copolymerized nylon were added thereto with 65 parts of methanol /
A solution dissolved in a mixed solvent of 30 parts of n-butanol was applied by a dipping method to form a 0.5 μm intermediate layer.

Next, the black angles (2θ ± 0.2 °) of the CuKα characteristic X-ray diffraction of 9.0 °, 14.2 ° and 23.9 were determined.
4 parts of oxytitanium phthalocyanine (TiOPc) having strong peaks at 2 ° and 27.1 ° and polyvinyl butyral (trade name: Eslec BM2, manufactured by Sekisui Chemical) 2
And 60 parts of cyclohexanone were dispersed in a sand mill using φ1 mm glass beads for 4 hours, and then 100 parts of methyl ethyl ketone was added to prepare a dispersion for a charge generation layer. This was applied by a dipping method to form a 0.3 μm charge generation layer.

Next, 10 parts of a charge transporting material having the following structural formula

[0058]

Embedded image And 10 parts of the polymer described in Condition 1 of Table 3 were dissolved in a mixed solvent of 30 parts of monochlorobenzene / 70 parts of dichloromethane.

This polymer is prepared from a predetermined biphenol (0.0
Sodium hydroxide (0.8 g) and tetramethylammonium chloride (1 g) dissolved in water (100 ml) and put into a 1 liter mixer, into which terephthalic acid chloride (0.1 mol) was added to 1,2-dichloroethane (30 mol). 0
05mol), isophthalic acid chloride (0.005mo)
The solution obtained by dissolving l) was added with stirring, stirred at a high speed for 10 minutes, and allowed to stand for 2 hours. Then, a 1,2-dichloroethane solution was collected, and a large amount of hexane was added thereto to collect as a polymer. After the recovery, a water-washed, chloroform-dissolved, purified methanol dropping step was used. This paint was applied by a dipping method and dried at 120 ° C. for 2 hours to form a charge transporting layer of 18 μm.

Next, the evaluation will be described. The surface film hardness was measured using a Fisher Scope H-100V manufactured by Fisher Instruments Co., Ltd., and the universal hardness (Hu) and the plastic deformation rate were determined. At this time, the maximum load was 10 at 25 ° C and 50% humidity.
0 mN and the load time was 20 seconds.

Next, Canon GP55 was used for evaluation after remodeling the optical system. The prepared electrophotographic photoreceptor was subjected to paper passing durability at 28 ° C. and 90% RH in this apparatus. The sequence was in a continuous endurance mode. Early endurance and 1
On the 0000 sheets, the potential at a minute point was measured on the electrophotographic photosensitive member with a minute surface electrometer.
Simultaneous halftone images were taken to see if there was density unevenness.

In addition, the adhesion observed on the surface of the photoreceptor was 10
The number of sheets when more than one were attached was examined. When the toner ran out, it was replenished, and the image was durable until a problem occurred in the image. Further, a Taber abrasion tester using a polishing tape was used for abrasion for 15 minutes, and the weight loss at that time was measured. Table 4 shows the results.

(Examples 2 to 12) An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the binder of the charge transport layer was used under the conditions 2 to 12 shown in Table 3. Table 4 shows the results.

[0064]

[Table 3]

[0065]

[Table 4]

(Examples 13 to 24) Except that the binder of the charge transport layer used was one of the conditions 13 to 24 shown in Table 5,
An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1. Table 6 shows the results.

[0067]

[Table 5]

[0068]

[Table 6]

(Comparative Examples 1 to 5) An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the binder resin for the charge transport layer used was one of the conditions 1 to 3 shown in Table 7. Table 8 shows the results.

[0070]

[Table 7]

[0071]

[Table 8]

[0072]

As described above, according to the present invention, excellent friction resistance is obtained.
It has become possible to provide an electrophotographic photosensitive member, a process cartridge, and an electrophotographic apparatus capable of increasing the uniformity of potential due to durability, making toner fusion less likely to occur, and supplying a good image.

[Brief description of the drawings]

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

Claims (6)

[Claims] An electron having a conductive support and an organic photosensitive layer.
In the photographic photoreceptor, the surface layer of the electrophotographic photoreceptor is
Conduct a surface film hardness test in an environment of 5% and humidity of 50%,
The resulting universal hardness value (Hu) is 2
30N / mm ^Two≤ Hu ≤ 700 N / mm^TwoAnd the table
Plastic deformation of the surface layer by indenter used for surface film hardness test
An electrophotograph wherein the ratio satisfies the following expression (1):
Photoconductor: [Equation 1] 2. In the electrophotographic photoreceptor, the surface layer of the electrophotographic photoreceptor is subjected to a surface film hardness test at 25 ° C. in an environment of 50% humidity, and the indenter used at that time is a Vickers square pyramid diamond indenter, Maximum load is 5mN ~ 30
The universal hardness value (Hu) obtained between 0 mN is 2
Using an electrophotographic photoreceptor in which 30 N / mm ² ≦ Hu ≦ 700 N / mm ² and the plastic deformation rate of the surface layer by the indenter satisfies the following formula (1), a dot-like shape is formed on the photoreceptor. According to an electrophotographic apparatus having an exposure unit for forming an electrostatic latent image, the effective developing light area in the dot-shaped still image is 6
Electrophotographic apparatus having a spot diameter of 0 μm or less: 3. In the electrophotographic photoreceptor, the surface layer of the electrophotographic photoreceptor is subjected to a surface film hardness test at 25 ° C. in a 50% humidity environment, and a Vickers square pyramid diamond indenter used at that time is used. Load is 5mN ~ 300
The universal hardness value (Hu) obtained during mN is 23
0N / mm ² ≦ Hu ≦ 700 N / mm ² , and the plastic deformation rate of the surface layer by the indenter is expressed by the following equation (1). Is satisfied, and a polymer having a structural unit represented by the following structural formula (1) is contained in the surface layer: In the formula, X is —CR ₃ R ₄ — (where R ₃ and R ₄ are each independently a hydrogen atom, a trifluoromethyl group, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms) ), An optionally substituted 1,1-cycloalkylene group having 5 to 11 carbon atoms, an α, ω-alkylene group having 2 to 10 carbon atoms, a single bond, -O-, -S-, -SO- Or -SO ₂
-. R ₁ and R ₂ each independently represent a hydrogen atom, a halogen atom, an alkyl group which may be substituted, an aryl group, or an alkylene group, and a and b each independently represent 0 to 4;
The electrophotographic photoreceptor according to claim 1, wherein the surface layer contains a polymer having a structural unit represented by the following structural formula (2) or (3). Embedded image Embedded image (Wherein, R ₅ and R ₆ represent hydrogen, an optionally substituted alkyl group and a halogen atom, x and y each represent an integer of 1 or more, and m and n each represent an integer of 10 or more) 4. In the electrophotographic apparatus, the surface layer of the electrophotographic photosensitive member is subjected to a surface film hardness test at 25 ° C. in a 50% humidity environment, and a Vickers quadrangular pyramid diamond indenter used at that time is used. Is 5mN ~ 300m
The universal hardness value (Hu) obtained between N is 230
N / mm ² ≦ Hu ≦ 700 N / mm ² , and the plastic deformation rate of the surface layer by the indenter is represented by the following equation (1). Is satisfied, and a polymer having a structural unit represented by the following structural formula (1) is contained in the surface layer: In the formula, X is —CR ₃ R ₄ — (where R ₃ and R ₄ are each independently a hydrogen atom, a trifluoromethyl group, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms) ), An optionally substituted 1,1-cycloalkylene group having 5 to 11 carbon atoms, an α, ω-alkylene group having 2 to 10 carbon atoms, a single bond, -O-, -S-, -SO- Or -SO ₂
-. R ₁ and R ₂ each independently represent a hydrogen atom, a halogen atom, an alkyl group which may be substituted, an aryl group, or an alkylene group, and a and b each independently represent 0 to 4;
The electrophotographic apparatus according to claim 2, wherein the surface layer contains a polymer having a structural unit represented by the following structural formula (2) or (3). Embedded image Embedded image (Wherein, R ₅ and R ₆ represent hydrogen, an optionally substituted alkyl group and a halogen atom, x and y each represent an integer of 1 or more, and m and n each represent an integer of 10 or more) 5. The electrophotographic apparatus according to claim 2, wherein the electrophotographic photoreceptor according to claim 1 or at least one selected from the group consisting of a charging unit, a developing unit and a cleaning unit. A process cartridge which integrally supports the means and is detachable from the main body of the electrophotographic apparatus. 6. The electrophotographic apparatus according to claim 2 or 4, wherein the electrophotographic photosensitive member according to claim 1 or 3, a charging unit, a developing unit, and the image exposure unit according to claim 2. An electrophotographic apparatus having a transfer unit.