JP2003076050A - Electrophotographic device and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic device and a process cartridge capable of stably keeping high image quality without causing a fogging inherent to an injection electrifying system even after endurable service to repetitive use under a high humidity environment. SOLUTION: This electrophotographic device is equipped with a conductive particle carrier having conductivity and elasticity on its surface and an electrifying means having the conductive particles carried on the carrier, having 10 nm to 10 μm particle size and arranged in contact with an electrophotographic sensitive body. The electrophotographic sensitive body is characterized in that it has a photoreceptive layer and a charge injection layer as a surface layer on a supporting body and the film thickness d (μm) of the charge injection layer, the elastic deformation rate We (OCL) (%) of the charge injection layer and the elastic deformation rate We (CTL) (%) of the photoreceptive layer satisfy a following condition (1). The electrophotographic device having such characteristic and the process cartridge for the electrophotographic device are provided. -0.71×d+We (CTL)<=We (OCL)<=0.03×d<3> -0.89×d<2> +8.43×d+We (CTL)...(1).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus and a process cartridge, and more specifically, charging in which charges are directly injected from a charging member in contact with the electrophotographic photosensitive member onto the surface of the electrophotographic photosensitive member. The present invention relates to an electrophotographic apparatus and a process cartridge using the method.

[0002]

2. Description of the Related Art In the electrophotographic method, for example, an electrophotographic photosensitive member using selenium, cadmium sulfide, zinc oxide, amorphous silicon, organic photoconductor, etc. is charged,
Exposure, development, performs the basic process such as a transfer and fixing, in its charging process, conventionally, by using a corona mostly generated by applying a high voltage (DC5~8kV) a metal wire There is. However, in this method, corona products such as ozone and NOx deteriorate the electrophotographic photoconductor to promote image blurring and deterioration, and wire stains affect image quality, resulting in image white spots and black streaks. There was a problem such as.

In particular, an electrophotographic photosensitive member whose photosensitive layer is mainly composed of an organic photoconductor has lower chemical stability than other selenium photosensitive members and amorphous silicon photosensitive members and is exposed to corona products. Then, a chemical reaction (mainly an oxidation reaction) occurs, which tends to cause deterioration. Therefore, when repeatedly used under corona charging, there is a tendency that the image blurring due to the above-mentioned deterioration and the sensitivity decrease, the copy density becomes low due to the increase of the residual potential, and the printing (copying) resistance life becomes short.

In the case of corona charging, the current flowing to the electrophotographic photosensitive member is 5% to 30% of the current, and most of the current flows to the shield plate, so that the charging means is inefficient in terms of electric power. there were.

Therefore, in order to compensate for such problems,
For example, JP-A-57-178267 and JP-A-56
-104351, JP-A-58-40566, JP-A-58-139156, and JP-A-58-
As proposed in Japanese Patent No. 150975, etc., a method of charging without using a corona discharger has been studied. More specifically, by bringing a charging member such as a conductive elastic roller to which a direct current voltage of about 1 to 2 kV is applied from the outside into contact with the surface of the electrophotographic photosensitive member, the surface of the electrophotographic photosensitive member has a predetermined potential. It is a method of charging to.

However, this method is more disadvantageous than the corona charging method in terms of non-uniform charging and occurrence of dielectric breakdown of the electrophotographic photosensitive member. For example, a length of 2 to 200 m in a direction perpendicular to the moving direction of the surface to be charged.
m, width of 0.5 mm or less causes stripe-shaped charging unevenness, and white stripes (a phenomenon that white stripes appear in a solid black or halftone image) in the positive development method, and in the reverse development method. Image defects such as black streaks occur.

In order to solve such problems and improve the uniformity of charging, a method has been proposed in which an AC voltage is superimposed on a DC voltage and applied to a charging member (JP-A-63-63). (See Japanese Patent No. 149668). In this charging method, uniform charging is performed by applying a pulsating current voltage obtained by superimposing an AC voltage (Vac) on a DC voltage (Vdc).

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

However, in order to prevent image defects, if the superposed AC voltage is raised, the maximum applied voltage of the pulsating current voltage also increases, and therefore, a slight defect portion inside the electrophotographic photosensitive member causes dielectric breakdown due to discharge. It becomes easy to get up. In particular, when the electrophotographic photosensitive member is an organic photoconductor having a low withstand voltage, this dielectric breakdown is remarkable. When the dielectric breakdown occurs, the image is white in the longitudinal direction of the contact portion in the positive development method, and black stripes are generated in the reverse development method.

Further, since the discharge in the minute voids is utilized, image blurring occurs due to the deterioration of the surface layer due to NOx, ozone, etc., and the influence of adhesion of low resistance substances. Furthermore, since the charging member is in contact with the electrophotographic photosensitive member and the electric field strength is much higher than that of corona charging, there is a problem that the electrophotographic photosensitive member is easily scraped and the durability is poor.

In order to solve these problems, a process of charging by directly injecting an electric charge into the electrophotographic photosensitive member with almost no discharge is being studied.

In the case where the charging for directly injecting this electric charge into the electrophotographic photosensitive member (hereinafter, also referred to as injection charging) is dominant, and the case where the discharge is dominant (hereinafter, also referred to as discharge charging), There is a big difference in the mechanism.

In the case of discharge charging, as shown in FIG. 1, the discharge is first started when the voltage applied to the charging member is equal to or higher than the discharge start voltage, and thereafter, the portion where the applied voltage exceeds the discharge start voltage is electrophotographic photosensitive. It becomes the surface potential of the body. That is, in the case of charging using discharge with only DC voltage, the applied voltage Vdc
And the body surface potential Vd of the electrophotographic photosensitive material are expressed by the following formula (6).
become that way. In FIG. 1, the horizontal axis (V) represents the voltage Vdc (V) applied from the power source. Also, the dark attenuation of Vd is not taken into consideration. | Vd | ≈ | Vdc | − | Vth | (6) {wherein Vth (discharge start voltage) = (7737.7 ×)
D) ^1/2 + 312 + 6.2 × DD = L (photosensitive layer film thickness μ
m) / K (relative permittivity of photosensitive layer)}

On the other hand, in the case of injection charging, as shown in FIG. 1, the applied voltage of the charging member and the surface potential of the electrophotographic photosensitive member are almost the same, and there is no threshold like the discharge starting voltage in the case of discharging. Is characteristic. That is, when at least the following expression (7) is established, injection charging may occur. | Vdc |-| Vd | <| Vth | (7) However, this condition alone includes the case where the surface potential Vd of the electrophotographic photosensitive member becomes higher due to frictional charging. Further, when the expression (6) is charging using discharge, the value of (Vdc-Vd) in the expression (7) is Vt.
Injection charging may occur near h, but discharge is considered to be dominant.

Therefore, assuming that the discharge-dominant charging is the following formula (8): | Vth / 2 | <| Vdc |-| Vd | <Vth (8) The injection-dominant charging is the following formula (3). Can be shown as | Vdc |-| Vd | ≤ | Vth / 2 | (3)

Further, let the case of applying the electrophotographic photoreceptor to a DC voltage Vdc plus ac voltage Vac (V) from the charging member thought with reference to FIG. This charging is generally called an AC / DC superposition system. AC voltage Va
When the peak-to-peak voltage of c is Vpp (V), in the case of discharge charging, Vpp is set so as to satisfy the following formula (9) in order to stabilize charging, the surface potential of the electrophotographic photosensitive member is Is expressed by the following equation (10). | Vpp | ≧ 2 × | Vth | (9) | Vd | ≈ | Vdc | (10) In other words, in AC / DC discharge charging, the condition of Expression (9) should be satisfied in order to stabilize the charging property. The voltage applied to the primary charging member is set.

However, when Vpp is in the condition of the following formula (11), the surface potential of the electrophotographic photosensitive member becomes the value of the following formula (12). | Vpp | <2 × | Vth | (11) | Vd | ≈ | Vpp / 2 | + | Vdc | − | Vth | (12) That is, DC component Vdc (V) of the applied voltage and discharge start voltage Vth (V ) Datosuruto is constant, the peak-to-peak voltage Vpp of the ac voltage (V) is gradually decreased, the surface potential Vd of an electrophotographic photosensitive member (V) is gradually decreased as it,
When Vpp becomes 0, it becomes the same as DC charging, and equation (6)
Is the same as Further, in consideration of the dark decay of the electrophotographic photosensitive member, the formula (12) is more accurate when written as the following formula (13). | Vd | ≦ | Vpp / 2 | + | Vdc | − | Vth | (13)

On the other hand, A in the charging where injection charging is dominant
In the C / DC superposition system, the AC component has a strong auxiliary meaning, and Vpp is usually not so strong. That is,
Vpp is given so that the expression (11) is satisfied. Here, the point that the injection charging is largely different from the discharge charging is that the surface potential of the electrophotographic photosensitive member is substantially the same as the DC component of the voltage applied to the charging member when the injection charging is dominant. . That is, the expression (3) is established in the charging in which the injection charging is dominant. Further, the following expression (14) is established instead of the expression (13). | Vd |> | Vpp / 2 | + | Vdc |-| Vth | (14)

As described above, the charging method in which the injection charging is dominant and the discharge charging are completely different charging methods regardless of whether the voltage applied to the charging member is DC or the AC / DC superposition system. I understand.

In the charging in which injection charging is predominant, the charge is directly injected into the electrophotographic photosensitive member, so that it is not accompanied by discharge, or is slight even if accompanied by discharge. It can be said that the charging is ideal because there is almost no deterioration and there is little electrical damage to the electrophotographic photosensitive member.

[0021]

However, in order to satisfactorily perform the above-mentioned injection charging, the charging member has a speed difference with respect to the electrophotographic photosensitive member, and the charging member and the electrophotographic photosensitive member are different from each other. It is necessary to carry charged particles having a relatively high hardness on the contact surface of. Therefore, in this process, a large load is applied to the surface of the electrophotographic photosensitive member, and the surface is easily scratched. Further, a problem peculiar to this charging method, such as fogging due to durability under high humidity, was likely to occur.

An object of the present invention is to have excellent durability against scratches caused by electrification, and even after repeated use in a high humidity environment, without fog peculiar to the electrification system, and with high image quality. An object of the present invention is to provide an electrophotographic apparatus and a process cartridge that can keep the temperature stable.

[0023]

That is, the present invention is directed to an electrophotographic photosensitive member, a conductive particle carrier having conductivity and elasticity on the surface, and a particle size of 10 nm to 10 nm carried on the carrier.
An electrophotographic apparatus having the charging means having a conductive particle of 10 μm and arranged in contact with the electrophotographic photosensitive member, and charging the electrophotographic photosensitive member by directly injecting an electric charge into the electrophotographic photosensitive member. In the electrophotographic photosensitive member, the electrophotographic photosensitive member has a photosensitive layer and a charge injection layer as a surface layer on a support, the thickness d (μm) of the charge injection layer, and the elastic deformation rate We (OCL ) (%) And the elastic deformation rate We (CTL) (%) of the photosensitive layer satisfy the following expression (1). −0.71 × d + We (CTL) ≦ We (OCL) ≦ 0.03 × d ³ −0.89 × d ² + 8.43 × d + We (CTL) (1)

Further, the present invention is a process cartridge which integrally supports an electrophotographic photosensitive member and a charging means and is attachable / detachable to / from an electrophotographic apparatus, wherein the charging means has a conductive and elastic surface. Directly injecting charges to the electrophotographic photosensitive member, having a particle carrier and conductive particles carried on the carrier and having a particle size of 10 nm to 10 μm and arranged in contact with the electrophotographic photosensitive member. In the process cartridge for charging the electrophotographic photoreceptor, the electrophotographic photoreceptor has a photosensitive layer and a charge injection layer as a surface layer on a support, and the film thickness d (μm) of the charge injection layer. The process cartridge is characterized in that the elastic deformation rate We (OCL) (%) of the charge injection layer and the elastic deformation rate We (CTL) (%) of the photosensitive layer satisfy the following expression (1). −0.71 × d + We (CTL) ≦ We (OCL) ≦ 0.03 × d ³ −0.89 × d ² + 8.43 × d + We (CTL) (1)

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, d (μm),
It is further preferable that We (OCL) (%) and We (CTL) (%) satisfy the following formula (2). −0.71 × d + We (CTL) ≦ We (OCL) ≦ −0.247 × d ² + 4.19 × d + We (CTL) (2)

The elastic deformation rate We% in the present invention was measured by using a hardness meter (H100VP-HCU) manufactured by Fischer KK. Hereinafter, this is called a Fischer hardness tester. All measurement environments were performed under the environment of 23 ° C./55% RH.

The Fischer hardness tester is not a method in which an indenter is pushed into the surface of a sample and a residual dent after unloading is measured with a microscope like the conventional micro-Vickers method, and hardness is not continuously obtained, but the indenter is continuously loaded. It is a method of directly measuring the indentation depth under load to determine continuous hardness.

The elastic deformation rate is measured as follows. That is, a load is applied with a diamond indenter having a facing angle of 136 ° with a quadrangular pyramid and pushed into the film to 1 μm,
Then, the load is reduced and the indentation depth and the load until the load becomes 0 are measured. FIG. 3 is an example of the case where a coating film having a film thickness of 30 μm is measured at the indentation depth of about 3 μm using the hardness meter. In the figure, the relationship between the load and the indentation depth is A → B. → It is C. The work amount We (nJ) of elastic deformation at this time is represented by the area surrounded by C-B-D-C in FIG. 3, and the work amount Wr (nJ) of plastic deformation is shown in FIG.
The elastic deformation ratio We% in the present invention is represented by the following formula (15). We% = {We / (We + Wr)} × 100 (15)

In general, elasticity is a property in which an object strained (deformed) by an external force tries to restore the strain, and the object exceeds the elastic limit or removes the external force due to other influences. After that, what remains as a part of strain is plastic deformation. That is, the larger the elastic deformation rate We%, the larger the elastic deformation amount, and the smaller the We% value, the larger the plastic deformation amount.

In the present invention, with respect to the electrophotographic photosensitive member having the charge injection layer formed on the photosensitive layer, the elastic deformation ratio We () of the charge injection layer measured from above the charge injection layer using a Fisher hardness tester OCL) (%) and elastic deformation rate We of the photosensitive layer measured from above the photosensitive layer after peeling off the charge injection layer
Based on (CTL) (%), the relationship between them is sought. The elastic deformation rate of the charge injection layer and the photosensitive layer is, as shown in FIG. 4, the elastic deformation rate We (CTL) of the underlying photosensitive layer.
(%) (The position where the film thickness of the charge injection layer is 0), and the curve depending on the film thickness of the charge injection layer is in an open relationship.

The left side of equation (1) {-0.71 × d + W
e (CTL)} is an approximate expression obtained from the results of the example, but since the film thickness of the charge injection layer can be approximated to a straight line from 1 to 8 μm, it is a linear expression with respect to the film thickness. . If the elastic deformation rate of the charge injection layer is above the left side, no problem occurs.

The right side {0.03 × d ³ −0.89 ×
d ² + 8.43 × d + We (CTL)} is also an approximate expression obtained from the result of the example, but a problem occurs until the elastic deformation rate We (OCL) (%) of the charge injection layer exceeds this. If it exceeds this, fog occurs due to durability under high humidity. This is because if the elastic deformation of the charge injection layer becomes too large, high-resistance particles such as paper powder and toner external additives will be easily embedded in the charge injection layer, and charges will be injected into the embedded location. Therefore, it is considered that the electric potential is lowered and fog may occur. This phenomenon is caused by roughening the surface of the electrophotographic photosensitive member by the conductive particles when the conductive particles are present between the elastic carrier and the electrophotographic photosensitive member as in the present invention. , Especially noticeably. Further, even when the conductive particle carrier rotates in the opposite direction at the contact portion with the electrophotographic photosensitive member, the surface of the electrophotographic photosensitive member is likely to be roughened, so that this phenomenon is particularly remarkable. Further, as a cause of this phenomenon becoming particularly remarkable under high humidity, it is considered that the adsorption of water in the high humidity of the external additive of paper powder or toner also has an effect, but the true reason for this is still unclear. Not understood.

Further, the right side of the equation (2) {-0.247 × d
^{In the case of 2} + 4.19 × d + We (CTL)} or less, the fog did not occur at all, and a very good image was stably obtained.

In the present invention, the charge injection layer preferably contains conductive particles and lubricating particles.

Examples of the conductive particles used in the charge injection layer include metals, metal oxides, carbon black and the like. Examples of the metal include aluminum, zinc, copper, chromium, nickel, silver, stainless steel, and the like, or those obtained by vapor-depositing these metals on the surface of plastic particles. As the metal oxide, zinc oxide, titanium oxide,
Examples thereof include tin oxide, antimony oxide, indium oxide, bismuth oxide, indium oxide doped with tin, tin oxide doped with antimony or tantalum, and zirconium oxide doped with antimony. 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.

The volume average particle diameter of the conductive particles used in the charge injection layer is preferably 0.3 μm or less, and particularly preferably 0.1 μm or less in view of transparency of the charge injection layer.

Further, in the present invention, it is particularly preferable to use a metal oxide among the above-mentioned conductive particles in terms of transparency.

The lubricating particles used in the charge injection layer are fluorine atom-containing resin particles, silicone resin particles, silica particles, alumina particles and the like. In the present invention, fluorine atom-containing resin particles are particularly preferable. The fluorine atom-containing resin particles used in the present invention include tetrafluoroethylene, trifluoroethylene chloride resin, hexafluoroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin and It is preferable to appropriately select one kind or two or more kinds from these copolymers, and a tetrafluoroethylene resin and a vinylidene fluoride resin are particularly preferable. The molecular weight of the resin particles and the particle size of the particles can be appropriately selected and are not particularly limited.

Inorganic particles such as silica particles and alumina particles may not function as lubricating particles alone, but by dispersing and adding them, the surface roughness of the charge injection layer becomes large, The number of contact points is reduced with respect to the one in contact with the surface of the photoconductor, and as a result, the lubricity of the charge injection layer is increased. Lubricating particles used in the present invention include particles that impart such lubricity.

In order to prevent the particles of the fluorine atom-containing resin from aggregating in the charge injection layer solution, a fluorine atom-containing compound may be added. When the conductive particles are contained, the fluorine atom-containing compound may be added during dispersion of the conductive particles, or the surface of the conductive particles may be surface-treated with the fluorine atom-containing compound. By adding a fluorine atom-containing compound or subjecting the conductive particles to a surface treatment, the dispersibility and dispersion stability of the conductive particles and the fluorine atom-containing resin particles in the resin solution are higher than in the case without the fluorine atom-containing compound. Is greatly improved. In addition, by forming a secondary particle of dispersed particles by dispersing fluorine atom-containing resin particles in a liquid in which a fluorine atom-containing compound is added and conductive particles are dispersed, or in which a surface-treated conductive particle is dispersed. In addition, a coating liquid that is very stable and has good dispersibility over time can be obtained.

Examples of the fluorine atom-containing compound in the present invention include a fluorine-containing silane coupling agent, a fluorine-modified silicone oil and a fluorine-based surfactant.
Examples of preferable compounds are shown in Tables 1 to 3, but the present invention is not limited to these compounds.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

[Table 3]

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,
Examples include a method of attaching a surface treatment agent to the surface of the conductive particles. As the dispersing means, a usual dispersing means such as a ball mill or a sand mill can be used. Then, the solvent may be removed from the obtained dispersion solution and fixed on the surface of the conductive particles. Further, if necessary, further heat treatment may be performed thereafter. Further, a catalyst for accelerating the reaction can be added to the treatment liquid. Furthermore, if necessary, the surface-treated conductive particles can be further pulverized.

The ratio of the fluorine atom-containing compound to the conductive particles is influenced by the particle size of the particles, but is preferably 1 to 65 mass% with respect to the total mass of the surface-treated conductive particles, and particularly, It is preferably from 1 to 50 mass%.

As described above, the dispersion of the fluorine atom-containing resin particles is stable by dispersing the conductive particles after adding the fluorine atom-containing compound or by using the conductive particles surface-treated with the fluorine atom-containing compound. In addition, a charge injection layer having excellent slipperiness and releasability can be formed. However, with recent progress in high durability, further higher hardness, higher printing durability and higher stability have been demanded.

As the binder resin for the charge injection layer used in the present invention, a curable resin is preferable, and an acrylic resin, an epoxy resin, a polyurethane resin and a siloxane resin are particularly preferable. Above all, it is preferable to use the phenol resin because the environmental change of the resistance of the charge injection layer is small. Further, it is preferable to use a curable phenol resin, particularly a thermosetting resol-type phenol resin, from the viewpoint that the surface hardness is hard, the abrasion resistance is excellent, the dispersibility of fine particles and the stability after dispersion are also excellent. .

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

Monomers of phenols, dimethylolphenols, trimethylolphenols, and their mixtures, or their oligomers, which are obtained by reacting these phenols with aldehydes under an alkaline catalyst, and Make a mixture of monomers and oligomers. Among them, a relatively large molecule having a repeating structural unit of about 2 to 20 is an oligomer, and one is a monomer.

The alkali catalysts used include metal-based alkali compounds, ammonia and amine compounds, and the metal-based alkali compounds include NaOH and KOH.
And hydroxides of alkali metals and alkaline earth metals such as Ca (OH) _{2 and the} like, and amine compounds include, but are not limited to, hexamethylenetetramine, trimethylamine, triethylamine and triethanolamine. is not. In the present invention, it is preferable to use ammonia and an amine compound in consideration of the fluctuation of resistance under a high humidity environment, and it is more preferable to use an amine compound in consideration of the stability of the solution.

When the charge injection layer in the present invention contains a thermosetting resin, it is usually cured in a hot air drying oven after the charge injection layer is coated on the photosensitive layer. At this time, the curing temperature is preferably 100 ° C to 300 ° C,
It is particularly preferably 120 ° C to 200 ° C.

In the present invention, "the resin is cured" means that the resin is not dissolved in an alcohol solvent such as methanol or ethanol.

The thickness of the charge injection layer is 0.5 μm to 1
The thickness is preferably 0 μm, and particularly preferably 1 μm to 7 μm.

In the present invention, an additive such as an antioxidant may be added to the charge injection layer.

The physical properties of the charge injection layer defined by the present invention include the types of materials used for the charge injection layer, the mixing ratio of the materials used, the particle size and dispersion state of the particles contained, the solid content concentration of the solution before curing, It is affected by various factors such as the curing conditions, the film thickness, and the constitution of the photosensitive layer, but in the present invention, it is important to satisfy the above physical properties, and the means for achieving it is not particularly limited. Generally, for example, the curing temperature is high, the curing time is long, the solid content concentration of the solution is high, the ratio of the resin in the solid content is low, the boiling point of the solvent is low, and the elastic deformation value becomes large. There is a tendency.

Next, the photosensitive layer will be described.

The photoconductor of the present invention has a laminated structure. Figure 5
In the electrophotographic photosensitive member (a), a charge generation layer 53 and a charge transport layer 52 are sequentially provided on a conductive support 54, and a charge injection layer 51 is further provided on the outermost surface.

Further, as shown in FIGS. 5B and 5C,
An undercoat layer 55 and a conductive layer 56 for the purpose of preventing interference fringes may be provided between the conductive support and the charge generation layer.

As the conductive support 54, a support itself having conductivity, for example, aluminum, aluminum alloy or stainless steel can be used. In addition, aluminum, aluminum alloy or indium oxide-tin oxide alloy, etc. can be used. The conductive support or plastic having a layer formed by vacuum deposition and conductive fine particles (for example, carbon black, tin oxide, titanium oxide and silver particles) are impregnated into plastic or paper together with an appropriate binder resin. The above-mentioned support, plastic having a conductive binder, and the like can be used.

An undercoat layer having a barrier function and an adhesive function can be provided between the conductive support and the photosensitive layer. The undercoat 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.

For the undercoat layer, casein, polyvinyl alcohol, ethyl cellulose, ethylene-acrylic acid copolymer, polyamide, modified polyamide, polyurethane,
It can be formed of gelatin or aluminum oxide. The thickness of the undercoat layer is preferably 5 μm or less,
˜3 μm is more preferred.

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

The solvent used for the charge generation layer coating material is selected from the solubility and dispersion stability of the resin and the charge generation material used, but as the organic solvent, alcohols, sulfoxides, ketones, ethers, Esters, aliphatic halogenated hydrocarbons, aromatic compounds and the like can be used.

The charge generating layer is uniformly formed by a method such as a homogenizer, an ultrasonic wave, a ball mill, a sand mill, an attritor or a roll mill together with the binder resin and the solvent in an amount of 0.3 to 4 times the mass ratio of the above charge generating material. Dispersed and applied,
It is dried and formed. The thickness is preferably 5 μm or less, and particularly preferably in the range of 0.01 to 1 μm.

As the charge transport material, a hydrazone compound, a pyrazoline compound, a styryl compound, an oxazole compound, a thiazole compound, a triarylmethane compound or a polyarylalkane compound can be used. It is not limited.

The charge transport layer is generally formed by dissolving the above charge transport material and the binder resin in a solvent and applying the solution. The mixing ratio of the charge transport material and the binder resin is 2: 1 by mass ratio.
It is preferably about 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, chlorinated hydrocarbons such as chlorobenzene, chloroform and carbon tetrachloride are used. To be

As the binder resin used for forming the charge transport layer, acrylic resin, styrene resin,
A resin selected from polyester resin, polycarbonate resin, polyarylate resin, polysulfone resin, polyphenylene oxide resin, epoxy resin, polyurethane resin, alkyd resin, unsaturated resin and the like is preferable. Particularly preferred resins include polymethylmethacrylate resins,
Examples thereof include polystyrene resin, styrene-acrylonitrile copolymer, polycarbonate resin and polyarylate resin. The thickness of the charge transport layer is preferably 5 to 40 μm, and particularly preferably 10 to 30 μm.

Further, the charge generation layer or the charge transport layer may contain various additives such as an antioxidant, an ultraviolet absorber and a lubricant.

When applying these solutions, for example,
A coating method such as a dip coating method, a spray coating method and a spinner coating method can be used, and the drying is preferably at 10 ° C to 200 ° C, more preferably at a temperature in the range of 20 ° C to 150 ° C, preferably for 5 minutes. It can be carried out under blast drying or static drying for a time of 5 hours, more preferably 10 minutes to 2 hours.

In the present invention, the charge injection layer is applied and cured on the photosensitive layer. Alternatively, the charge injection layer may be applied and cured after the charge generation layer is applied on the charge transport layer. Further, the charge injection layer may be applied and cured on a single-layer photosensitive layer containing the charge generation material and the charge transport material in the same layer.

FIG. 6 shows an example of a schematic structure of an electrophotographic apparatus equipped with the process cartridge of the present invention. In this apparatus, a primary charging member 2, an exposure unit 5, a developing unit 6, and a transfer unit 7 are arranged around an electrophotographic photosensitive member 1.

First, a voltage is applied to the primary charging member 2 to charge the surface of the photoconductor 1 and an image corresponding to a document is exposed on the surface of the photoconductor 1 by the exposing means 5 to form an electrostatic latent image. Next, the toner in the developing means 6 is attached to the photoconductor 1 at the developing portion a to develop (visualize) the electrostatic latent image on the photoconductor 1. Furthermore, the toner image formed on the photoconductor 1 is transferred onto the transfer material P such as paper supplied by the transfer means 7, and the residual toner remaining on the photoconductor 1 without being transferred to the transfer material is cleaned by a cleaner or the like. To collect. In recent years, cleanerless systems have also been studied, and residual toner can be directly collected by a developing means. Further, after the static elimination processing is performed by the pre-exposure from the pre-exposure means, it is repeatedly used for image formation. The pre-exposure means is not always necessary.

The toner image transferred to the transfer material P is fixed on the transfer material P by the fixing means 8.

In the image forming apparatus shown in FIG. 6, the light source of the exposing means 5 is a halogen light, a fluorescent lamp, a laser light, an LED.
Etc. can be used. Also, other auxiliary processes may be added if necessary.

In the present invention, a plurality of constituent elements such as the photosensitive member 1, the primary charging member 2, the developing means 6 and the cleaning means are integrally combined as a process cartridge, and the process cartridge is formed. May be detachably attached to the main body of the electrophotographic apparatus such as a copying machine or a printer. For example, at least one of the primary charging member 2, the developing unit 6 and the cleaning unit is attached to the photoreceptor 1.
In addition, the process cartridge 9 can be integrally supported and formed into a cartridge, and the process cartridge 9 can be attached to and detached from the apparatus main body by using guide means such as the rail 10 of the apparatus main body.

When the electrophotographic apparatus is a copying machine or a printer, the exposure light L uses reflected light or transmitted light from the original document, or a signalized original document is a laser beam emitted according to this signal. The light is emitted by scanning a beam, driving an LED array, driving a liquid crystal shutter array, and the like.

In FIG. 6, 6a is a rotary developing sleeve,
6b is a magnet roll, and S1 to S3 are power supplies.

The charging means of the present invention shown in FIGS. 6 and 7 includes a conductive elastic roller 2 (hereinafter referred to as a charging roller), conductive particles 3 (hereinafter also referred to as a charged particle) for the purpose of promoting charging, and Regulation member 4 which is a charged particle supply means
Have. At the contact portion n between the charging roller and the photoconductor 1,
The photoconductor 1 is charged while the charged particles 3 are applied. As a result, the charging roller 2 can come into contact with the photoconductor 1 with a speed difference, and at the same time, the charge can be directly injected into the photoconductor 1 very densely via the charged particles 3. Therefore, in the present invention, it is possible to obtain a high charging efficiency which has not been obtained by the conventional roller charging, and it is possible to apply a potential almost equal to the potential applied to the charging roller to the photoconductor.

Next, the main constituent members of the charging means used in the present invention will be described.

<Charging Roller> The charging roller 2 is manufactured by forming a medium resistance layer 2b of rubber or foam on the cored bar 2a. The medium resistance layer 2b includes a resin (for example, urethane), conductive particles (for example, carbon black),
It was formulated with a sulfiding agent, a foaming agent, etc., and formed into a roller shape on the cored bar 2a. After that, the surface was polished as needed to prepare an elastic conductive roller 2 having a diameter of 12 mm and a longitudinal length of 250 mm. When the roller resistance of this example was measured, it was 100 kΩ. Total pressure 1k on the core of roller 2
While being pressed to an aluminum drum of φ30 mm so that a load of g is applied, 1
00V was applied and measured. Here, it is important that the elastic roller 2 functions as an electrode. That is, it is necessary to have elasticity so as to obtain a sufficient contact state, and at the same time, have a sufficiently low resistance to charge the moving photoconductor 1. On the other hand, it is necessary to prevent voltage leakage when the photoconductor 1 has a defective portion such as a pinhole. When an organic photoreceptor is used as the photoreceptor 1, a resistance of 10 ⁴ to 10 ⁷ Ω is preferable in order to obtain sufficient chargeability and leak resistance.

If the hardness of the charging roller is too low, the shape of the charging roller is not stable, so that the contactability is poor. If the hardness is too high, not only a sufficient contact area cannot be secured, but also the microscopic contactability of the surface of the photoconductor is poor. Asker C hardness is 2
The preferred range is 5 degrees to 50 degrees.

The material of the charging roller is not limited to the elastic foam, but the material of the elastic body may be EPD.
Examples thereof include a rubber agent in which a conductive substance such as carbon black or a metal oxide is dispersed in M, urethane, NBR, silicone rubber, IR or the like for resistance adjustment, or a material obtained by foaming these. It is also possible to adjust the resistance by using an ion conductive material without particularly dispersing the conductive substance.

The charging member is not limited to the charging roller, and an elastic body such as a fur brush in which each pile has elasticity can be used. Here, the fur brush roller has a resistance-adjusted fiber (such as Rec made by Unitika) planted on a pile with a density of 155 fibers / mm ² and a fiber length of 3 mm, and then the pile is wound and fixed on a core metal of φ6 mm, It is formed into a roller shape.

<Charged particles> In this embodiment, the specific resistance is 10
Conductive zinc oxide particles 3 having an average particle diameter of ⁶ μm · 3 μm were used.

As the material for the particles, various kinds of conductive particles such as conductive inorganic particles such as other metal oxides and mixtures with organic substances can be used. The resistance of the particles is preferably 10 ¹⁰ Ω · cm or less in order to transfer charges through the particles. The resistance was measured by the tablet method and normalized. Specifically, about 0.5 g of the powder sample was placed in a cylinder having a bottom area of 2.26 cm ² , 15 kg of pressure was applied to the upper and lower electrodes, and at the same time a voltage of 100 V was applied to measure the resistance value. Normalized to calculate the specific resistance.

The particle size is 10 nm to 10 μm. If it is less than 10 nm, particles cannot be stably obtained. On the other hand, if it exceeds 10 μm, the charging member cannot sufficiently densely inject charges into the electrophotographic photosensitive member, so that good charging uniformity cannot be obtained. To measure the particle size, 100 or more particles were extracted from observation by an optical or electron microscope, the volume particle size distribution was calculated with the maximum chord length in the horizontal direction, and the 50% average particle size was determined. In the present invention, the particle size when the particles are formed as aggregates is defined as the average particle size of the aggregates.

FIG. 8 is also a view showing the schematic arrangement of the electrophotographic apparatus of the present invention, which uses a toner recycling process (cleanerless system). The points different from the electrophotographic apparatus shown in FIG. 6 will be described below.

<Overall Schematic Structure of Electrophotographic Apparatus> This electrophotographic apparatus does not include an independent charged particle feeder. The charged particles are added to the developer and accumulated, and are supplied to the charging roller 2 via the photoconductor 1 together with the development of the toner.

Reference numeral 60 is a developing means. The electrostatic latent image on the photoconductor 1 is developed as a toner image at the developing portion a by the developing device 60. In the developing device 60, a mixture tm in which conductive particles m are added to the developer t is provided.

The electrophotographic apparatus of this embodiment employs a toner recycling process, and the transfer residual toner remaining on the photoconductor 1 after image transfer is not removed by a dedicated cleaner (cleaning device). The photoconductor 1 and its contact portion n are temporarily collected by the charging roller 2 which rotates in the counter direction, and as the toner orbits around the outer circumference of the roller, the reversed toner charges are normalized and sequentially discharged onto the photoconductor 1 to develop portions. In the case of “a”, the developing means 60 collects and reuses by cleaning at the same time as development.

<Charging Roller> The configuration is the same as that described above except that the charged particle feeder is not provided.

<Developing Means> The developing means 60 is a reversal developing device using a one-component magnetic toner (negative toner) as the developer t. In the developing device, a mixture tm of a developer (toner) t and charged particles m is provided.

Reference numeral 60a denotes a non-magnetic rotary developing sleeve as a developer carrying / conveying member which encloses the magnet roll 60b, and the pre-development mixture t provided in the developing container 60e.
The toner t in m is subjected to layer thickness regulation and electric charge imparted by the regulation blade 60c in the process of being conveyed on the rotary developing sleeve 60a. Reference numeral 60d is a stirring member that circulates the toner in the container and sequentially conveys the toner to the periphery of the sleeve.

The toner t coated on the rotary developing sleeve 60a is conveyed by the rotation of the sleeve 60a to a developing portion (developing area) a which is a facing portion between the photosensitive member 1 and the sleeve 60a. A developing bias voltage is applied to the sleeve 60a from a developing bias applying power source S5.

In this embodiment, the developing bias voltage is D
The superimposed voltage of the C voltage and the AC voltage was used. As a result, the electrostatic latent image on the photoconductor 1 is reversely developed by the toner t.

<Toner> The one-component magnetic toner t, which is a developer, is prepared by mixing a binder resin, magnetic particles and a charge control agent, and kneading, pulverizing, and classifying the toner. It is produced by adding a fluidizing agent or the like as an external additive. The average particle diameter (D4) of the toner was 7 μm.

<Amount of Charged Particles Carried, Coverage> In the present embodiment, since the toner is recycled, the toner easily contaminates the surface of the charging roller. It is necessary for the toner to retain the electric charge due to triboelectrification on the surface, so 10 ¹³ Ω · c
It has a resistance of m or more. Therefore, when the charging roller is contaminated with the toner, the resistance of the charging particles carried on the charging roller increases, and the charging performance deteriorates. for example,
Even if the resistance of the charged particles is low, the resistance of the powder carried by the toner is increased, and the charging property is impaired. Therefore, the supported amount of charged particles is 0.1 to 100 mg / cm ^2.
Is preferable, and particularly 0.1 to 10 mg / cm
It is preferably ² . In this example, 5 mg
/ Cm ² . However, if that component contains a large amount of toner, the charging performance naturally lowers. In this case, the resistance of the supported particles increases, and the situation can be grasped. In other words, in actual use, the resistance of the particles (including the mixture of toner and paper powder) carried on the charging roller is preferably 10 ⁻¹ to 10 ¹² Ω · cm, and particularly 10 ⁻ It is preferably from ¹ to 10 ¹⁰ Ω · cm. The resistance measuring method is the same as described above.

Furthermore, it is more important to adjust the coverage of the charged particles in order to grasp the effective amount of the charged particles in charging. Since the charged particles are white, they can be distinguished from the magnetic toner black. The area showing white in observation with a microscope is obtained as an area ratio. When the coverage is 0.1 or less, the charging performance is insufficient even if the peripheral speed of the charging roller is increased. Therefore, it is preferable to keep the coverage of the charged particles within the range of 0.2 to 1. In this embodiment, it is set to 0.6.

In addition, the amount of carried particles can be basically adjusted by adjusting the amount of charged particles added to the developer.
If necessary, an elastic blade may be brought into contact with a part of the outer circumference of the charging roller for adjustment. By abutting the member, there is an effect of normalizing the triboelectric charging polarity of the toner, and it becomes possible to adjust the amount of particles carried on the charging roller.

In a system in which the means for supplying the charged particles is the developing means, it is more preferable that the amount of the charged particles transferred to the recording medium such as paper is smaller, and the amount remaining on the photoreceptor is larger. Is more preferable. In addition, the charged particles are
It is preferably positively charged. In the reversal development system, the developer is transferred to the light potential part of the photoreceptor and the charged particles are transferred to the dark potential part, and in the transfer process, only the developer is transferred to the transfer material, and the charged particles are transferred onto the photoreceptor. Remains in
This is because it is supplied to the charging roller and the charging becomes stable.

[0102]

EXAMPLES The present invention will be described in more detail with reference to examples below, 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.

(Examples 1 to 3) φ30 mm × 260.5
mm aluminum cylinder as a support, a 5% by mass solution of polyamide resin (trade name: Amilan CM8000, manufactured by Toray) in methanol was applied on the aluminum cylinder by a dipping method to form an undercoat layer having a thickness of 0.5 μm. .

Next, the Bragg angle (2θ ± 0.2 °) of CuKα characteristic X-ray diffraction, which is represented by the following formula, is 9.0.
4 parts of oxytitanium phthalocyanine pigment having strong peaks at °, 14.2 °, 23.9 ° and 27.1 °,

[Outer 1]

2 parts of polyvinyl butyral resin BX-1 (manufactured by Sekisui Chemical Co., Ltd.) and 80 parts of cyclohexanone were
It was dispersed for about 4 hours by a sand mill device using 1 mm glass beads. This dispersion is applied on the undercoat layer,
A charge generation layer having a thickness of 0.2 μm was formed.

Then, 10 parts of a compound represented by the following formula:

[Outside 2]

And bisphenol Z type polycarbonate (trade name: Z-200, manufactured by Mitsubishi Gas Chemical Co., Inc.) 10
Parts were dissolved in 100 parts monochlorobenzene. This solution was applied on the charge generation layer and dried in hot air at 105 ° C. for 1 hour to form a charge transport layer having a thickness of 20 μm.

Next, as a charge injection layer, 20 parts of antimony-doped tin oxide ultrafine particles surface-treated with a compound represented by the following formula (treatment amount 7%),

[Outside 3]

30 parts of antimony-doped tin oxide fine particles and 150 parts of ethanol surface-treated with methylhydrogen silicone oil (trade name: KF99, manufactured by Shin-Etsu Silicone Co., Ltd.) (treatment amount: 20%) were sand-milled.
Dispersion was performed for 66 hours, 20 parts of polytetrafluoroethylene fine particles (average particle diameter 0.18 μm) were further added, and dispersion was performed for 2 hours. Then, 30 parts of a resol type thermosetting phenolic resin (trade name: PL-4804; amine compound catalyst, manufactured by Gunei Chemical Industry Co., Ltd .: polystyrene equivalent average molecular weight by GPC of about 800) was dissolved as a resin component and blended. It was a liquid.

Using this prepared solution, a film having a plurality of thicknesses was formed on the above charge transport layer by a dip coating method, and 145 ° C.
The mixture was dried with hot air for 1 hour to obtain a charge injection layer. At this time, the film thickness of the obtained charge injection layer was measured by measuring the instantaneous multi-photometry system MCPD-2000 by light interference because it was a thin film.
(Manufactured by Otsuka Electronics Co., Ltd.), the film thickness is 1μ
m, 2 μm, 3 μm, 4 μm, 7 μm and 10 μm. The film thickness can also be measured by directly observing the cross section of the film of the photoreceptor with an SEM or the like. Further, the dispersibility of the charge injection layer preparation liquid was good, and the film surface was a uniform and even surface.

The elastic deformation ratio We% was measured using the above-mentioned Fisher hardness meter (H100VP-HCU). Elastic deformation rate We% is a quadrangular pyramid and the facing angle 136 of the tip is
1μ on the film to be measured by applying a load with a diamond indenter of °
Push to m and electrically detect and read the depth of pushing under load. As described above, the elastic deformation rate We% is the work of elastic deformation We (n) as shown in FIG.
J) and the plastic deformation work Wr (nJ), the above equation (1)
5) is used. The measurement was performed at 10 arbitrary points on the same sample, and the average was obtained at 8 points excluding the maximum and minimum values.

Elastic deformation rate from above the charge injection layer {We (O
CL)} is measured directly on the charge injection layer of the electrophotographic photosensitive member, and the elastic deformation rate {We (CTL)} of the photosensitive layer is measured on the photosensitive layer after the charge injection layer is removed. did.

As a method for removing the charge injection layer, a lapping tape (C
2000: Fuji Photo Film Co., Ltd. was used, but the present invention is not limited to this. However, the hardness of the photosensitive layer is measured by sequentially measuring the film thickness so that the charge injection layer is not over-polished and the photosensitive layer is not polished as much as possible.
Alternatively, while observing the surface, measurement is performed when the charge injection layer is completely removed.

However, the residual film thickness of the photosensitive layer is 10 μm.
It has been confirmed that almost the same value can be obtained in the above cases. Therefore, even if the photosensitive layer is slightly over-polished, almost the same value can be obtained when the residual film thickness of the photosensitive layer is 10 μm or more. It is preferable to measure in a state where the charge injection layer is eliminated as much as possible and the photosensitive layer is not polished as much as possible.

The evaluation of the test was carried out by visually observing the surface property of the photoconductor and then modifying a laser jet 4000 manufactured by Hewlett Packard Co., Ltd. as shown in FIG. 6 as follows.

As an evaluation, an image was visually evaluated after running 10,000 sheets under an environment of 32 ° C./86% RH. The elastic deformation rate was measured with a Fischer hardness meter to measure the thickness of the charge injection layer 1 μm, 2 μm, 3 μm,
m, 7 .mu.m and 10 .mu.m, the actual device evaluations such as image evaluation were performed with the charge injection layer having a thickness of 1 .mu.m (Example 1), 3 .mu.m (Example 2) and 7 .mu.m (Example 3). Using.

Table 4 shows the elastic deformation rate, the initial potential Vd (V) and the result of image evaluation after endurance.

<Evaluation apparatus 1> The produced electrophotographic photosensitive member was mounted on an electrophotographic apparatus obtained by modifying a printer (laser jet 4000) manufactured by Hewlett Packard as follows, and evaluated.

First, for the charged portion of the electrophotographic photosensitive member, the charging roller was prepared by forming a medium resistance layer of rubber on a 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 formed 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. 250 mm
The elastic conductive roller of was produced. When the resistance of this roller was measured, it was 100 kΩ. The measurement was performed by applying 100 V to the core metal and the conductive support in a state where the core metal of the roller was pressure-bonded to the electrophotographic photosensitive member so that a total pressure of 1 kg was applied.

In this example, conductive zinc oxide particles having a specific resistance of 10 ⁶ Ω · cm and an average particle size of 3 μm were used as the charged particles.

Further, in order to uniformly supply the charged particles to the contact portion between the roller and the photosensitive member, a charged particle coating means is provided. As a supply means, a regulation blade is brought into contact with the charging roller, and charged particles are held between the charging roller and the regulation blade. Then, a certain amount of charged particles is applied to the charging roller.

In this embodiment, the charging roller is rotated with a speed difference with respect to the electrophotographic photosensitive member. The electrophotographic photosensitive member has a drum shape with a diameter of 30 mm and a peripheral speed of about 1
It rotates at a constant speed of 10 mm / sec. The charging roller was driven at about 150 rpm so that the roller surface moved in the opposite direction at a constant speed at the contact portion with the photoreceptor, and a DC voltage of -620 V was applied to the roller core metal.

As a result, the surface of the photoconductor is charged to a potential almost equal to the applied voltage. In the present embodiment, the charging is performed by injection charging by the charged particles existing in the contact portion between the roller and the electrophotographic photosensitive member slidingly rubbing the surface of the electrophotographic photosensitive member without a gap. Also, the cleaning means was removed.

(Examples 4 and 5) In Example 2, the resol type phenol resin used for the charge injection layer was PL-4.
Example 2 except that BKS-316 (amine compound catalyst, manufactured by Showa Highpolymer Co., Ltd.) and PL-4804 whose molecular weight was increased to about 3000 by GPC were used instead of 804.
An electrophotographic photoreceptor was prepared and evaluated in the same manner as in. The results are shown in Table 4.

(Examples 6 to 8) An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 5 except that the resin component added was changed to 50 parts, 100 parts and 150 parts. did. The results are shown in Table 4.

(Example 9) An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 4, except that the amount of resin added was changed to 15 parts. The results are shown in Table 4.

(Examples 10 to 12) In Examples 6 to 8, the polycarbonate resin (viscosity average molecular weight 20000) as the binder resin for the charge transport layer was mixed with the viscosity average molecular weight 10000.
An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Examples 6 to 8 except that the electrophotographic photosensitive member was replaced by 0. The results are shown in Table 4.

(Example 13) An electron was prepared in the same manner as in Example 9 except that the polycarbonate resin (viscosity average molecular weight 20000) as the binder resin for the charge transport layer was changed to that having viscosity average molecular weight 100000. A photographic photoreceptor was prepared and evaluated. The results are shown in Table 4.

(Comparative Examples 1 to 3) In Examples 1 to 3,
The phenol resin used in the charge injection layer was replaced with 100 parts of the acrylic resin represented by the following formula, and the photopolymerization initiator was replaced with 2-
Dissolve 6 parts of methylthioxanthone to prepare a formulation,
A film was formed on the photosensitive layer by a dip coating method, photocured with a high pressure mercury lamp at a light intensity of 800 mW / cm ² for 30 seconds, and then dried with hot air at 120 ° C. for 100 minutes to prepare a charge injection layer. Was prepared and evaluated in the same manner as in Examples 1 to 3. The results are shown in Table 4.

[0130]

[Outside 4]

(Comparative Example 4) In Example 2, the conductive resin used in the charge injection layer and the polytetrafluoroethylene particles were not contained, and the phenol resin was methylphenylpolysiloxane (KF-50500CS: manufactured by Shin-Etsu Silicone Co., Ltd.). ), An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 2 except that the charge injection layer was made of resin only. The results are shown in Table 4.

Comparative Example 5 In Example 10, the phenol resin used in the charge injection layer was replaced with 100 parts of the acrylic resin used in Comparative Example 1, and 6 parts of 2-methylthioxanthone as a photopolymerization initiator was dissolved. A formulation solution is prepared, a film is formed on the photosensitive layer by a dip coating method, and photocuring is performed with a high pressure mercury lamp at a light intensity of 800 mW / cm ² for 30 seconds.
Thereafter, an electrophotographic photosensitive member was prepared and evaluated in the same manner as in Examples 10 to 12 except that the charge injection layer was prepared by drying with hot air at 120 ° C for 100 minutes. The results are shown in Table 4.

Comparative Example 6 In Example 10, the conductive resin used in the charge injection layer and the polytetrafluoroethylene particles were not contained, and the phenol resin was methylphenyl polysiloxane (KF-50500CS: manufactured by Shin-Etsu Silicone Co., Ltd.). ), An electrophotographic photosensitive member was prepared in the same manner as in Example 10 except that only the resin was used as the charge injection layer.
evaluated. The results are shown in Table 4.

(Examples 14 to 16) Examples 1 to 3 are the same as Examples 1 to 3, except that the electrophotographic apparatus is replaced by the injection charging system and the toner recycling process (cleanerless system) as shown in FIG. An electrophotographic photoreceptor was prepared and evaluated in the same manner as in. The results are shown in Table 4.

(Examples 17 and 18) In Example 15, the polystyrene-equivalent number average molecular weight of PL-4804 by GPC was increased to about 3000, and the amount of resin added was 100.
An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 15 except that the parts and 150 parts were replaced. The results are shown in Table 4.

Example 19 Example 15 was repeated except that the resin was changed to BKS-316 (amine compound catalyst, Showa Highpolymer Co., Ltd.) in Example 15 and the amount of resin added was changed to 15 parts. Create an electrophotographic photoreceptor in the same manner as
evaluated. The results are shown in Table 4.

(Comparative Examples 7 to 9) In Examples 14 to 16, the phenol resin used in the charge injection layer was replaced with 100 parts of the acrylic resin represented by the structural formula (5), and 2-methylthioxane was used as a photopolymerization initiator. 6 parts of Sonson is dissolved to prepare a preparation liquid, a film is formed on the photosensitive layer by a dip coating method, and photocuring is performed with a high pressure mercury lamp at a light intensity of 800 mW / cm ² for 30 seconds, and then 120 ° C. Example 1 except that the charge injection layer was prepared by hot air drying for 100 minutes.
An electrophotographic photosensitive member was prepared and evaluated in the same manner as in 4 to 16. The results are shown in Table 4.

(Comparative Example 10) In Example 15, the conductive resin used in the charge injection layer and the polytetrafluoroethylene particles were not contained, and the phenol resin was methylphenylpolysiloxane (KF-50500CS: manufactured by Shin-Etsu Silicone Co., Ltd.). ), An electrophotographic photosensitive member was prepared in the same manner as in Example 15 except that the charge injection layer was made of resin only.
evaluated. The results are shown in Table 4.

(Embodiment 20) Electrophotographic sensitization is performed in the same manner as in Embodiment 2 except that the voltage applied to the primary charger is DC voltage -620V and the peak-to-peak voltage Vpp of AC voltage is 200V. The body was evaluated. The results are shown in Table 4.
Shown in.

(Comparative Example 11) In Example 2, the evaluation apparatus 1 was modified so that the voltage applied to the primary charging member of the printer (laser jet 4000) manufactured by Hewlett-Packard Co. was applied so that only DC voltage of -620V was applied, and The electrophotographic photosensitive member was evaluated in the same manner as in Example 2 except that the electrophotographic apparatus was replaced with the one in which the cleaning means was simply removed. The results are shown in Table 4.

(Comparative Example 12) In Example 2, the voltage applied to the primary charging member of the printer (Laserjet 4000) manufactured by Hewlett Packard in the evaluation apparatus 1 was set to DC voltage -620V, and the peak-to-peak voltage Vpp of AC voltage was set to 200V. The electrophotographic photosensitive member was evaluated in the same manner as in Example 2 except that the electrophotographic apparatus was modified so as to be applied in a superimposed manner and the electrophotographic apparatus was simply replaced with the cleaning means removed.
The results are shown in Table 4.

(Example 21) PL-480 was used as the resol-type phenol resin used in the charge injection layer in Example 2.
An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 2 except that Priorphen J325 (ammonia catalyst, manufactured by Dainippon Ink and Chemicals, Inc., solid content 70%) was used instead of 4. When the charge injection layer had a thickness of 10 μm, a Benard cell was generated, and the prepared solution gelled in 3 days. The results are shown in Table 4.

(Comparative Example 13) An electrophotographic photosensitive member was evaluated in the same manner as in Example 2 except that the charge injection layer in Example 1 was formed as follows. The results are shown in Table 4.

100 parts of Ta ₂ O ₅ -doped tin oxide particles,
Resol type phenol resin (Priofen J32
5, ammonia catalyst, manufactured by Dainippon Ink and Chemicals, Inc.
Solid content 70%) 90 parts and methyl isobutyl ketone 30
0 parts were mixed and dispersed in a sand mill for 72 hours. This solution is spray coated on the charge transport layer and heated at 140 ° C. for 30 minutes.
By heating for a minute, a charge injection layer having a film thickness of 4 μm was formed.

The obtained photoreceptor did not satisfy the physical properties specified by the present invention. The reason is that the solid content concentration is lower and the solvent having a higher boiling point is used as compared with Example 21. The curing temperature is low, and the curing time is short.

The thickness of the charge injection layer is 7 μm and 10 μm.
Benard cells were generated in the case of μm, and the prepared solution gelled in 5 days.

[0147]

[Table 4]

[0148]

As described above, according to the present invention, it has excellent durability against scratches, has no fog peculiar to this charging system even after durability under high humidity, and has a high quality. It has become possible to provide an electrophotographic apparatus and a process cartridge capable of maintaining stable image quality.

[Brief description of drawings]

FIG. 1 is a diagram showing the difference between discharge charging and injection charging in the surface potential of an electrophotographic photosensitive member when only a DC voltage is applied to a charging member.

FIG. 2 is a diagram showing the difference between discharge charging and injection charging in the surface potential of an electrophotographic photosensitive member when a voltage in which an AC voltage is superimposed on a DC voltage is applied to a charging member.

FIG. 3 is an example of a measurement chart by a Fischer hardness meter.

FIG. 4 shows the elastic deformation rate We (O) measured from above the charge injection layer.
CL) (%) (However, at the position where the film thickness of the charge injection layer is 0, the elastic deformation rate We (CT) measured on the charge transport layer is
L) (%)}.

FIG. 5 is a diagram showing a layer structure of the electrophotographic photosensitive member of the present invention.

FIG. 6 is a diagram showing a schematic configuration of an electrophotographic apparatus of the present invention in Embodiment 1.

FIG. 7 is a diagram showing in detail conductive particle supply means of the electrophotographic apparatus of the present invention in Example 1.

FIG. 8 is a diagram showing a schematic configuration of an electrophotographic apparatus of the present invention in Example 14.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Koichi Nakata             Kyano, 3-30-2 Shimomaruko, Ota-ku, Tokyo             Within the corporation (72) Inventor Daisuke Tanaka             Kyano, 3-30-2 Shimomaruko, Ota-ku, Tokyo             Within the corporation F-term (reference) 2H068 AA03 AA05 BB31 BB35 BB57                       CA37 CA60                 2H200 FA01 FA02 FA14 FA18 FA19                       GA16 GA23 GA34 GB37 HA03                       HA21 HA28 HB12 HB17 HB22                       HB45 HB46 HB47 HB48 LA33                       LA38 MA03 MA08 MA14 MB01                       MB04 MB06 MC01 MC02 MC15                       NA02

Claims (15)

[Claims] 1. An electrophotographic photoconductor, a conductive particle carrier having conductivity and elasticity on the surface, and a particle size of 10 nm to 10 μm, which is carried on the carrier and contacts the electrophotographic photoconductor. An electrophotographic apparatus, comprising the charging means having conductive particles arranged therein, for charging the electrophotographic photosensitive member by directly injecting an electric charge into the electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is a support. There is a photosensitive layer and a charge injection layer as a surface layer on the top, and the film thickness d (μ
m), elastic deformation rate We (OCL) (%) of the charge injection layer
And an elastic deformation ratio We (CTL) (%) of the photosensitive layer satisfies the following expression (1). −0.71 × d + We (CTL) ≦ We (OCL) ≦ 0.03 × d ³ −0.89 × d ² + 8.43 × d + We (CTL) (1) 2. The electrophotographic apparatus according to claim 1, wherein d (μm), We (OCL) (%) and We (CTL) (%) satisfy the following formula (2). −0.71 × d + We (CTL) ≦ We (OCL) ≦ −0.247 × d ² + 4.19 × d + We (CTL) (2) 3. The electrophotographic apparatus according to claim 1, wherein the charge injection layer contains a curable resin. 4. The electrophotographic apparatus according to claim 3, wherein the curable resin is a resol-type phenol resin. 5. The electrophotographic apparatus according to claim 4, wherein the resol-type phenol resin is a resin synthesized by using an amine compound. 6. The electrophotographic apparatus according to claim 1, wherein the charge injection layer contains conductive particles. 7. The electrophotographic apparatus according to claim 6, wherein the charge injection layer contains lubricating particles. 8. The electrophotographic apparatus according to claim 1, wherein the charge injection layer has a film thickness of 1 μm to 7 μm. 9. The electrophotographic apparatus according to claim 1, wherein the conductive particles have a resistance of 10 ¹⁰ Ω · cm or less. 10. The electrophotographic apparatus according to claim 1, wherein the coverage of the conductive particle carrier of the conductive particles is 0.2 to 1.0. 11. The electrophotographic apparatus according to claim 1, wherein the conductive particle carrier rotates in the opposite direction at the contact portion with the electrophotographic photosensitive member. 12. The electrophotographic apparatus according to claim 1, wherein the conductive particle carrier has a resistance of 10 ⁴ to 10 ⁷ Ω. 13. The electrophotographic apparatus according to claim 1, wherein the conductive particle carrier has an Asker C hardness of 25 to 50 degrees. 14. The electrophotographic apparatus according to claim 1, wherein the conductive particle carrier has a surface layer containing an elastic foam. 15. A process cartridge, which integrally supports an electrophotographic photosensitive member and a charging means, and which is detachably mountable to an electrophotographic apparatus, wherein the charging means has a conductive particle carrier having a surface having conductivity and elasticity. The particle size carried on the carrier is from 10 nm to
A process cartridge having electrically conductive particles having a size of 10 μm disposed in contact with the electrophotographic photosensitive member and charging the electrophotographic photosensitive member by directly injecting an electric charge into the electrophotographic photosensitive member. The body has a photosensitive layer and a charge injection layer as a surface layer on a support, and the thickness d (μ
m), elastic deformation rate We (OCL) (%) of the charge injection layer
And a process cartridge characterized in that the elastic deformation rate We (CTL) (%) of the photosensitive layer satisfies the following expression (1). −0.71 × d + We (CTL) ≦ We (OCL) ≦ 0.03 × d ³ −0.89 × d ² + 8.43 × d + We (CTL) (1)