JP2003005392A - Electrophotographic photoreceptor, process cartridge and electrophotographic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor capable of outputting a high-grade image attended with little positive ghost even in a new charging system and to provide a process cartridge and an electrophotographic apparatus. SOLUTION: The electrophotographic photoreceptor is used in an electrophotographic apparatus having a charging means consisting of charged particles based on electrically conductive particles of 10 μm to 10 nm particle diameter and a charged particle carrier having an electrically conductive elastic surface and supporting the charged particles, wherein the charged particles come in contact with a body to be charged to charge the surface of the body to be charged. The resistance of the particles supported on the carrier is 10<12> -10<-1> Ω.cm and the amount of the particles supported is 0.1-50 mg/cm<2> . The photoreceptor has at least a photosensitive layer and an electric charge injection layer on an electrically conductive support and hole mobility μt (cm<2> /V.sec) in an electric field of 3×10<5> V/cm satisfies the formula μt>1×10<-6> cm<2> /V.sec. The process cartridge has the photoreceptor.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrophotographic photoreceptor,
More specifically, the present invention relates to a process cartridge and an electrophotographic apparatus. An electrophotographic photosensitive member using a charging system in which charging is dominant in which charges are directly injected from a charging member in contact with the electrophotographic photosensitive member to the surface of the photosensitive member, and the electrophotographic photosensitive member The present invention relates to a process cartridge having a body and an electrophotographic apparatus.

[0002]

2. Description of the Related Art In an electrophotographic method, an electrophotographic photosensitive member such as selenium, cadmium sulfide, zinc oxide, amorphous silicon and an organic photoconductor is charged, exposed, and exposed.
Basic processes such as development, transfer, and fixing are performed, but when this is done, most of the charging processes are conventionally performed on the metal wire at high voltage (DC5-8k).
V) is applied, and charging is performed by the generated corona. However, in this method, when corona occurs, the surface of the photoconductor is altered by corona products such as ozone and NOx,
There are problems such as image blurring and deterioration, wire stains affecting image quality, and image white spots and black streaks.

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, in terms of electric power, only 5 to 30% of the current is directed to the photoconductor, and most of the current flows to the shield plate, resulting in poor efficiency as a charging means. Furthermore, the concentration of ozone, NOx and the like increases by repeating the electrophotographic process by corona charging, which has been a serious problem in providing a comfortable use environment.

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 contacting and charging without using a corona discharger has been studied. To put it concretely, 1-2k from the outside
In this system, a charging member such as a conductive elastic roller to which a DC voltage of about V is applied is brought into contact with the surface of the photoconductor to charge the surface of the photoconductor to a predetermined potential.

However, the direct charging method is disadvantageous in comparison with the corona charging method in terms of nonuniform charging and occurrence of dielectric breakdown of the photosensitive member due to discharge when a voltage is directly applied. Here, due to the non-uniformity of charging, stripe-shaped charging unevenness is generated in a direction perpendicular to the moving direction of the surface to be charged, with a length of 2 to 200 mm and a width of 0.5 mm or less. Then, image defects such as white streaks (a phenomenon in which white streaks appear in a solid black or halftone image) that occur in the case of the positive development method and black streaks that occur in the case of the reverse development method are caused.

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, a pulsating voltage is obtained by superimposing an AC voltage (Vac) on a DC voltage (Vdc), and this is applied to perform uniform charging.

In this case, in order to maintain the uniformity of charging and prevent image defects such as white spots in the positive development system and black spots and fog in the reverse development system, the superposed AC voltage causes discharge start according to Paschen's law. It is necessary to have a peak-to-peak potential difference (Vpp) that is at least twice the voltage Vth.

However, if the superposed AC voltage is increased in order to prevent image defects, the maximum applied voltage of the pulsating current voltage causes dielectric breakdown due to discharge at a slight defective portion inside the photosensitive member. In particular, when the photoconductor is an organic photoconductor having a low withstand voltage, this dielectric breakdown is remarkable. In this case, in the positive development method, the image is white in the longitudinal direction of the contact portion (in the width direction of the recording material), and in the reverse development method, black stripes occur. Also, since the discharge is in a minute gap, the damage to the photoconductor is large, and the photoconductor is greatly scraped,
There was a problem that durability was inferior.

In order to solve these problems, the inventors of the present invention injected the charge directly onto the photosensitive member,
A process of charging is being studied. Furthermore, it was also found that, in the process of direct injection of electric charges, by superposing the AC voltage, the charging becomes more stable than in the case where only the DC voltage is applied.

There is a big difference between the case where the charging that directly injects the charges onto the photosensitive member is dominant and the case where the discharging is dominant. That is, as shown in FIG. 1, in the case of discharging, the difference is that the discharge is started only when the voltage applied to the charging member is equal to or higher than the discharge start voltage, and thereafter the photosensitive member is exposed by the amount by which the applied voltage exceeds the discharge start voltage. It is charged on the body. That is, in the case of discharge charging with only DC voltage, the applied voltage V
The relationship between dc and the photoreceptor surface potential Vd is as shown in equation (8). In FIG. 1, the horizontal axis (V) is the voltage Vd applied from the power source.
c (V). However, the dark attenuation of Vd is not taken into consideration.

| Vd | ≈ | Vdc | − | Vth | Equation (8) where Vth (discharge start voltage) = (7737.7 × D) ^1/2 +
312 + 6.2 × D D = d _SUM (sum of photosensitive layer thickness d _PC and charge injection layer thickness d _IN / μm) / K (relative permittivity of photosensitive layer)

On the other hand, in the charging in which the injection charging is dominant, as shown in FIG. 1, the applied voltage of the charging member and the surface potential of the photosensitive member are almost the same, and the threshold value such as the discharge starting voltage in the case of discharging is set. Another feature is that they do not have it. Although it is difficult to define injection charge as a dominant charge, injection charge may occur at least when the following expression (9) is satisfied.

[0014]     | Vdc |-| Vd | <| Vth | Equation (9)

However, under this condition, the expression (9) can be satisfied even if injection charging does not occur, such as when the photoreceptor surface potential Vd becomes higher due to frictional charging or when the resistance of the charging member becomes abnormally high. There is also a nature. Further, if the expression (8) is discharge charging, injection charging may occur at a value (Vdc-Vd) in the expression (9) close to Vth, but the discharge is dominant. Would be more appropriate. Therefore, assuming that the discharge-dominant charging is represented by Formula (10), | Vth / 2 | <| Vdc | − | Vd | <Vth Formula (10) The injection-dominant charging is represented by Formula (5). It is easy to understand if it is defined as.

[0016]     | Vdc | − | Vd | ≦ | Vth / 2 | Equation (5)

Consider a case where an alternating voltage Vac (V) in addition to the DC voltage Vdc is simultaneously applied from the primary charging member to the photosensitive member with reference to FIG. This charging is generally called an AC / DC superposition system.
The peak-to-peak voltage of the alternating voltage Vac is Vpp
In the case of (V), in the case of discharge charging, if Vpp is set so as to satisfy the following expression (11) in order to stabilize the charging, the photoreceptor surface potential becomes as shown in expression (12).

[0018]     | Vpp | ≧ 2 × | Vth | Equation (11)     | Vd | ≈ | Vdc | Equation (12)

That is, at the time of AC / DC discharge charging, the voltage applied to the primary charging member is set so as to satisfy the condition of formula (11) in order to stabilize the charging property.

However, when Vpp is in the condition as expressed by the formula (6), the surface potential of the photoconductor becomes a value as expressed by the formula (13).

[0021]     | Vpp | <2 × | Vth | Equation (6)     | Vd | ≈ | Vpp / 2 | + | Vdc | − | Vth | Equation (13)

That is, assuming that the DC component Vdc (V) of the applied voltage and the discharge start voltage Vth (V) are constant, when the peak-to-peak voltage Vpp (V) of the alternating voltage is gradually decreased, the surface of the photoconductor is gradually reduced. The potential Vd (V) decreases accordingly, and when Vpp becomes 0, it becomes similar to DC charging and becomes the same as the expression (8). Further, in consideration of the dark decay of the photoconductor, the expression (13) may be more accurate as the expression (14).

[0023]     | Vd | ≦ | Vpp / 2 | + | Vdc | − | Vth | Equation (14)

On the other hand, A in charging in which 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 to the extent that equation (6) holds. Here, the injection charging is largely different from the discharge system in that, in the charging in which the injection charging is dominant, the surface potential of the photoconductor is almost the same as the DC component of the voltage applied to the charging member.
That is, in the charging in which the injection charging is dominant, the equation (5)
Holds. Furthermore, not the equation (14), but the equation (7) holds.

[0025]     | Vd |> | Vpp / 2 | + | Vdc |-| Vth | Formula (7)

As described above, it is understood that the charging method in which the injection charging is dominant and the discharge charging method are completely different charging methods both when only DC is applied from the charging member and when the AC / DC superposition system is used. In the charging in which injection charging is predominant, the electric charge is directly injected onto the photoconductor, so that it is not accompanied by discharge, or is slight even if accompanied by discharge, so there is little deterioration due to NOx or ozone due to discharge, In addition, the damage to the photoconductor is very small, the photoconductor is hardly scraped, and it can be said that the charging is excellent as never before.

On the other hand, however, in the case of conventional contact charging involving discharge, the voltage applied to the charging roller in contact is high, and the electric field strength inside the photosensitive member at that portion depends on the target charging potential of the surface. It is higher than the electric field strength.
Further, in the case of corona charging, the electric field applied to the electrophotographic photosensitive member during charging is not much different from that during injection charging because the distance between the charger and the electrophotographic photosensitive member is large even if the applied voltage is high. The width of the charger itself is considerably wider than the nip width of the charging member in injection charging. By this,
The number of surplus charges accumulated inside the photoconductor was small.
However, in the case of injection charging, the electric field applied to the photoconductor during charging does not greatly exceed the electric field strength due to the charging potential of the photoconductor, and the width of the charging member is relatively narrow.
Therefore, a phenomenon that excess charges inside the photosensitive layer tend to stay is likely to occur. Further, in the case of the photoreceptor having the constitution of the present invention, the charge injection layer is provided on the photosensitive layer. However, since the manner of movement of charges is completely different, the charge injection layer is particularly different between the photosensitive layer and the charge injection layer. Also in the case, the retention of electric charges tends to increase.

Due to these two factors, in the electrophotographic photoreceptor and apparatus of the present invention, excessive charges are generated especially in the photosensitive layer, as compared with the case where the photoreceptor having no charge injection layer is charged by the usual contact charging method. It is easy to stay, and as a result, the so-called positive ghost in which the first high-density image portion is darker than the original density in the subsequent electrophotographic process is aggravated. In particular, when the movement of the charge in the photosensitive layer is uneven, the electric field applied to the photosensitive layer weakens when the charge on the surface starts to be canceled by the charge in the photosensitive layer. Transfer of the electric charge
It becomes weaker, and as a result, the accumulated charges tend to increase. Further, in the present invention, the charge injection layer is preferably provided by a curable resin from the viewpoint of the surface strength of the photoreceptor, but when a curable resin is used, the photosensitive layer is cured when the surface protective layer is cured. In addition, due to the addition of high energy such as extra heat and light, the characteristics inside the photosensitive layer are deteriorated, and uneven charge transfer and charge retention are more likely to occur than usual, making the above-mentioned positive ghost even worse. Phenomena were often seen.

[0029]

The charging method of the present invention comprises:
Since there is no discharge or only a small amount of discharge, there is little deterioration due to NOx and ozone due to discharge, and the damage to the photoconductor is also very small, and the abrasion of the photoconductor is small. However, the electric field applied to the photoconductor is made stronger than the electric field at the time of charging in the conventional contact charging process, and the charge generated by the surface charge injection layer or the interface between the photosensitive layer and the surface charge injection layer is There was a problem peculiar to this charging process in that the retention of charges and the retention of charges due to the deterioration of the photosensitive layer due to the thermal curing of the surface charge injection layer were added, and the positive ghost became worse.

An object of the present invention is to provide an electrophotographic photosensitive member capable of outputting a high-quality image in which positive ghost hardly occurs even in the above-mentioned novel charging system.

Another object of the present invention is to provide a process cartridge and an electrophotographic apparatus having the above electrophotographic photosensitive member.

[0032]

According to the present invention, charged particles having conductive particles having a particle size of 10 μm to 10 nm as a main component and a surface having conductivity and elasticity and carrying the charged particles are provided. The charged particles have a charging means for contacting the charged body and charging the surface of the charged body, and the particles carried on the support have a resistance of 10 ¹² to 1 1.
0 ⁻¹ Ω · cm, and the supported amount of the particles is 0.1 mg / c
An electrophotographic photosensitive member used in an electrophotographic apparatus having an m ^{2 to} 50 mg / cm ² , wherein the electrophotographic photosensitive member has at least a photosensitive layer and a charge injection layer on a conductive support, and 3
There is provided an electrophotographic photoreceptor characterized in that the hole mobility μ _t under an electric field of × 10 ⁵ V / cm satisfies the following formula (1); μ _t > 1 × 10 ⁻⁶ cm ² / V · sec formula (1)

Further, according to the present invention, there is provided an electrophotographic photosensitive member and a primary charging member disposed in contact with the photosensitive member, and the primary charging member is an elastic charging member forming a nip portion with the photosensitive member. The conductive particles are present in the nip portion between the primary charging member and the electrophotographic photosensitive member, and a voltage is applied to the photosensitive member from the primary charging member to directly charge the surface of the photosensitive member. In an electrophotographic photosensitive member used in an electrophotographic apparatus that can be charged by injection, the electrophotographic photosensitive member has at least a photosensitive layer and a charge injection layer on a conductive support, and has an electric conductivity of 3 × 10 ⁵ V / cm. There is provided an electrophotographic photosensitive member characterized in that hole mobility μ _t under an electric field satisfies the following formula (2); μ _t > 7 × 10 ⁻⁶ cm ² / V · sec formula (2)

Further, according to the present invention, there are provided a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

[0035]

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

For the injection charging process as in the present invention,
There is no superposition of voltage above the charging potential of the photoconductor,
Therefore, excess charges are likely to stay inside the photosensitive layer. Further, the electrophotographic photosensitive member of the present invention is characterized in that a charge injection layer is provided on the photosensitive layer. However, the charge injection layer conducts electrons in an electric resistance film prepared by conductive particles or the like. On the contrary, in the photosensitive layer, holes are hopping in the photoconductive layer such as the charge transport material, and the conduction mechanisms are completely different.

As a result, the present invention has a driving force in which excess charges in the photosensitive layer are removed, that is, an electric field applied to the photosensitive member at the time of charging is not strong, and further has an interface between layers having different conductive mechanisms in the structure of the photosensitive member. In the case of the electrophotographic photosensitive member of, especially, the excess charge is likely to be retained, and as a result,
If all the charges generated in the first exposure are not completely removed from the photoconductor by the next charging process and the surface of the next photoconductor is exposed, in particular, the photosensitive layer and surface charge injection in the photoconductor. The charges retained in the vicinity of the layer are transferred to the surface and cancel the surface charged charges. As a result, the exposed surface and the unexposed area in the previous electrophotographic process do not have the same surface potential even after a uniform injection charging process, and as a result, the image density changes.

As a result of detailed study of the mechanism of this image defect, the present inventors have found that the hole mobility μ _t (cm ² / V · s) of the electrophotographic photosensitive member under an electric field of 3 × 10 ⁵ V / cm.
It was found that the above-mentioned image defects can be suppressed by using an electrophotographic photosensitive member characterized in that ec) satisfies the following formula (1) in the injection charging process of the present invention; μ _t > 1 × 10 ⁻⁶ cm ² / V · sec formula (1)

The charge injection layer of the electrophotographic photoreceptor of the present invention is
It is a surface layer, and it is preferable to use a curable resin as the binder resin from the viewpoint of strength. In particular, when a thermosetting resin is used as the curable resin, the photosensitive layer is deteriorated due to the heating history during the formation of the charge injection layer. Therefore, the hole mobility defined in the present invention is It must be defined by the values measured after the layers are applied.

<Embodiment 1> FIG. 3 is a schematic configuration diagram in which a specific charging device is used in the electrophotographic apparatus of the present invention. The image recording apparatus of this embodiment is a laser printer (recording apparatus) that uses a transfer type electrophotographic process, a direct injection charging system, and a toner recycling process (cleanerless system).

(1) The overall schematic structure 1 of the electrophotographic apparatus is an image carrier, and in the present embodiment is a rotating drum type negative polarity OPC photosensitive member (negative photosensitive member, hereinafter referred to as photosensitive drum) having a diameter of 30 mm. The photosensitive drum 1 is rotationally driven in the arrow direction at a constant peripheral speed of 94 mm / sec (= process speed PS, printing speed).

The charging roller 2 is composed of charged conductive particles M (conductive particles as charged particles), a medium resistance layer 2b as a particle carrier and a core metal 2a. The charging roller 2 comes into contact with the photosensitive drum 1 with a predetermined amount of intrusion, and the contact portion n
To form.

The charging roller 2 is rotationally driven in the charging contact portion n in a direction (counter) opposite to the rotation direction of the photosensitive drum 1, and contacts the surface of the photosensitive drum 1 with a speed difference. Further, the charging roller 2 is used when recording an image on the printer.
A predetermined charging bias is applied from the charging bias applying power source S1. As a result, the peripheral surface of the photosensitive drum 1 is uniformly contact-charged to a predetermined polarity and potential by the direct injection charging method. In the example described later, a DC voltage of -700V was applied as the bias applied by the power source of S1.

The conductive particles are added to the developer, accumulated, and supplied to the charging roller via the photosensitive drum together with the development of the toner.

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

The printer of this embodiment is a toner recycling process, and the transfer residual toner remaining on the surface of the photosensitive drum 1 after image transfer is a dedicated cleaner (cleaning device).
Is temporarily removed by the charging roller that counter-rotates with the rotation of the photosensitive drum 1 without being removed by the rotation of the photosensitive drum 1, and as the toner circulates around the outer circumference of the roller, the inverted toner charges are normalized and sequentially discharged to the photosensitive drum to the developing portion a. At the same time, the developing device 60 collects and reuses by cleaning at the same time as development.

Reference numeral 4 is a laser beam scanner (exposure device) including a laser diode, a polygon mirror and the like. The laser beam scanner 4 outputs laser light whose intensity is modulated corresponding to the time-series digital image signal of the target image information, and scans and exposes the uniformly charged surface of the rotary photosensitive drum 1 with the laser light. The scanning exposure light L forms an electrostatic latent image on the surface of the rotary photosensitive drum 1 corresponding to the target image information.

Reference numeral 7 is a fixing device such as a heat fixing system. The transfer material P that has been fed to the transfer nip portion b and has undergone the transfer of the toner image on the photosensitive drum 1 side is separated from the surface of the rotating photosensitive drum 1 and is introduced into the fixing device 7 to receive the toner image fixing. And is discharged outside the apparatus as an image formed product (print / copy).

Next, the main members will be individually described in detail.

(2) Charging Roller In the charging roller 2 of this embodiment, a medium resistance layer 2b of rubber or foam is formed on a core metal 2a.

The medium resistance layer 2b is formulated with a resin (for example, urethane), a sulfiding agent, a foaming agent, etc., and is formed in a roller shape on the core metal 2a. Then, the surface was polished.

The charging roller according to the present invention differs from the charging roller for discharge generally used in the following points.

I. Surface structure and roughness characteristics for supporting high-density charged conductive particles on the surface II. Resistance characteristics required for direct charging (volume resistance, surface resistance)

(2) -1 Surface Structure and Roughness Characteristic Conventionally, the roller surface due to discharge is flat and the average surface roughness R
It is sub μm or less in a and the roller hardness is also high. In charging using electric discharge, the electric discharge phenomenon occurs in a gap of several tens of μm, which is slightly apart from the contact portion between the roller and the drum. When the roller and drum surfaces have irregularities, the electric field strength is partially different and the discharge phenomenon becomes unstable, resulting in uneven charging. Therefore, the conventional charging roller requires a flat and hard surface.

Then, why can't injection charging be performed with the discharging charging roller? Although the surface structure as described above seems to be in close contact with the drum in appearance, it hardly contacts in the sense of the microscopic contact property at the molecular level necessary for charge injection.

On the other hand, the conductive elastic roller of the present invention is required to have a certain degree of roughness because the charged conductive particles must be carried at a high density. 1 μm to 500 μm in terms of average roughness Ra
Is preferred. If it is less than 1 μm, the surface area for supporting the particles is insufficient, and if an insulator (for example, toner) or the like adheres to the surface layer of the roller, its periphery cannot contact the drum, and the charging performance deteriorates. On the other hand, when it exceeds 500 μm, the unevenness of the roller surface reduces the in-plane charging uniformity of the body to be charged. Average roughness Ra in Examples described later
Was 40 μm.

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

(2) -2 Resistance Characteristics In a conventional charging roller using electric discharge, a low resistance base layer is formed on a core metal, and then the surface is covered with a high resistance layer. The roller charging due to discharge has a high applied voltage, and if there is a pinhole (exposure of the support due to damage to the film), the voltage drops to the periphery thereof and charging failure occurs. Therefore, it is necessary to make it 10 ¹¹ Ω □ or more.

On the other hand, in the direct injection charging method of the present invention, since charging at a low voltage is possible, it is not necessary to make the surface layer have high resistance, and the roller can be composed of a single layer. Rather, in the direct injection charging, the surface resistance of the charging roller needs to be 10 ⁴ to 10 ¹⁰ Ω. 10 ¹⁰
When it exceeds Ω, the uniformity in the charged surface is deteriorated, unevenness due to the rubbing of the roller appears as streaks in the halftone image, and the image quality is deteriorated. On the other hand, if it is less than 10 ⁴ Ω, a peripheral voltage drop will occur due to the drum pinhole even with injection charging.

Further, the volume resistance is 10^Four-10⁷Ω
It is preferably in the range of. 10 ^FourIf less than Ω,
It is easy to cause a voltage drop in the power supply due to pinhole leakage.
It On the other hand, 10⁷If it exceeds Ω, the current required for charging is
It is no longer possible to secure the charge voltage, and the charging voltage drops.

The surface resistance and volume resistance of the charging roller used in this embodiment were 10 ⁷ Ω and 10 ⁶ Ω.

The roller resistance was measured by the following procedure.
FIG. 4 shows a schematic diagram of the structure at the time of measurement. The roller resistance was measured by applying an electrode to an insulating drum 43 having an outer diameter of 30 mm so that the core metal 2a of the charging roller 2 was applied with a total pressure of 1 kg. As the electrode, the guard electrode 41 was arranged around the main electrode 42, and the measurement was performed by the wiring diagram shown in FIG. The distance between the main electrode and the guard electrode was adjusted to about the thickness of the elastic layer 2b so that the main electrode had a sufficient width with respect to the guard electrode. The measurement was performed by applying +100 V from the power source S4 to the main electrode, measuring the currents flowing through the ammeters Av and As, and measuring the volume resistance and the surface resistance, respectively.

As described above, regarding the charging roller of the present invention, I. Surface structure roughness characteristics for supporting high-density charged conductive particles on the surface layer II. The resistance characteristics (volume resistance, surface resistance) necessary for direct charging are required.

(2) -3 Other roller characteristics In the direct injection charging system, it is important that the charging member functions as a flexible electrode. In a magnetic brush,
This is realized by the flexibility of the magnetic particle layer itself. In the present charging device, the elastic characteristics of the medium resistance layer 2b are adjusted to achieve this. The Asker C hardness is preferably in the range of 15 to 50 degrees. More preferably, it is 25 to 40 degrees. If it is too high, the required penetration amount cannot be obtained and the charging contact portion n cannot be secured between the charged body and the charging performance, and the contact performance at the molecular level of the substance cannot be obtained. Prevents contact with its surroundings. On the other hand, if the hardness is too low, the shape irregularity is not stable, so that the contact pressure with the body to be charged becomes uneven, resulting in uneven charging. Alternatively,
Poor charging occurs due to permanent deformation distortion of the roller after being left for a long time. In Examples described later, a roller having an Asker C hardness of 22 degrees was used.

(2) -4 Charging Roller Material, Structure, and Dimensions As the material of the charging roller 2, EPDM, urethane, N
Examples thereof include BR and silicone rubber, and rubber materials in which a conductive substance such as carbon black or metal oxide for resistance adjustment is dispersed in IR or the like. It is also possible to adjust the resistance by using an ion conductive material without dispersing the conductive substance. Then, if necessary, surface roughness is adjusted and molding is performed by polishing or the like. Further, a structure having a plurality of layers with separated functions is also possible.

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

In the examples described later, the diameter is 6 mm and the longitudinal length is 24.
An elastic layer having a porous surface on a core metal of 0 mm (layer thickness 3 m
m), the outer diameter is 12 mm, and the elastic layer length is 220
A charging roller 2 having a size of mm was manufactured. The charging roller 2 is arranged at an intrusion amount of 0.3 mm with respect to the photosensitive drum 1 as a member to be charged, and in the embodiment, a charging contact portion n of about 2 mm is formed.

(3) Developing Device The developing device 60 of this embodiment is a reversal developing device using a one-component magnetic toner (negative toner) as the developer t. In the developing device, a mixture t of a developer (toner) t and conductive particles m
It has m.

Reference numeral 60a denotes a non-magnetic rotary developing sleeve as a developer carrying / conveying member which encloses a magnet roll 60b, and the pre-development mixture t provided in the developing container 60e.
The toner t in m is subjected to the layer thickness regulation and the charge application 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 rotated by the rotation of the sleeve 60a, and a developing portion (developing area portion) which is an opposing portion between the photosensitive drum 1 and the sleeve 60a.
It is transported to a. 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 a superposed voltage of DC voltage and AC voltage. As a result, the electrostatic latent image on the photosensitive drum 1 side is reversely developed by the toner t.

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

(3) -b Charged conductive particles In this embodiment, the charged conductive particles have a specific resistance of 10 ⁶
A conductive zinc oxide having an Ω · cm and an average particle diameter of 3 μm was used.
Then, the charged conductive particles m are accommodated in the developing device together with the developer.

The material of the conductive particles m is a mixture with other conductive inorganic particles such as metal oxides or organic substances, or
Various conductive particles such as surface-treated particles can be used. Further, since the charged particles in the present invention do not need to be magnetically restrained, they need not have magnetism.

The particle resistance needs to be 10 ¹² Ω · cm or less as the specific resistance in order to transfer charges through the particles.
It is preferably 10 ¹⁰ Ω · cm or less.

The resistance was measured by the tablet method and normalized. That is, about 0.5 g of conductive particles are put in a cylinder having a bottom area of 2.26 cm ² , 15 kg of pressure is applied to the upper and lower electrodes, a voltage of 100 V is applied at the same time, and the resistance value is measured. Was calculated.

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

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

The conductive particles are preferably white or nearly transparent so as not to interfere with latent image exposure, especially when used for charging a photoreceptor. Further, considering that the conductive particles are partially transferred from the photosensitive member to the transfer material P, colorless or white particles are preferable in color recording. Also, in order to prevent light scattering due to particles during image exposure, the particles are The diameter is preferably equal to or smaller than the constituent pixel size, and more preferably equal to or smaller than the toner particle diameter. The lower limit of the particle diameter is considered to be 10 nm as a particle that can be stably obtained. Further, the conductive particles are more preferably positively charged.

A method of measuring the charge amount of toner particles in the present invention will be described below with reference to FIG. 23 ° C / relative humidity 6
Iron powder carrier DSP-138, 19.6 under 0% environment
A mixture of g and 0.4 g of conductive particles is put in a polyethylene bottle having a volume of 50 to 100 ml and shaken by hand 50 times. Next, 1.0 to 1.2 g of the mixture is put into a metal measuring container 92 having a 500-mesh screen 93 on the bottom, and a metallic lid 94 is placed on it. At this time, the total mass of the measurement container 92 is weighed and set as W1 (g). Next, the suction device 91
(At least the portion in contact with the measurement container 92 is an insulator), suction is performed from the suction port 97, the air flow rate control valve 96 is adjusted, and the pressure of the vacuum gauge 95 is set to 4900 hPa. In this state, suction is performed for 1 minute to remove the toner by suction. The potential of the electrometer 99 at this time is V (volt). Here, 98 is a capacitor, and the capacitance is C (μF). In addition, the mass of the entire measurement container after suction is weighed and is W2 (g). The triboelectric charge amount (μC / g) of this toner is calculated by the following formula.

[0081]     Triboelectric charge amount (μC / g) = CV / (W1-W2) Formula (15)

The triboelectric charge amount of the electrically conductive particles for charging used in the present invention with respect to the iron powder carrier was +5 μC / g.

(4) Conductive Particle Carrying Amount and Coverage In this embodiment, since the toner recycle structure is adopted, a larger amount of toner contaminates the surface of the charging roller as compared with the charging method in which the conductive particle supplying means is separately held. The toner has a resistance value of 10 ¹³ Ω · cm or more in order to maintain electric charges due to frictional charging on the surface. Therefore, when the roller is contaminated with the toner, the resistance of the particles carried on the roller is increased and the charging performance is deteriorated. For example, even if the resistance of the charged conductive particles is low, the resistance of the powder carried by the mixing of the toner rises and the chargeability is impaired. Therefore,
It is essential that the supported amount is 0.1 to 50 mg / cm ² , and preferably 0.1 to 10 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 rises and the situation can be grasped. That is, in actual use, the resistance of the particles (including the mixture of toner and paper powder) carried on the charging roller is measured by the above-mentioned method, and the value is 10 ⁻¹ to 10 ¹² Ω ·
cm is essential, and preferably 10 ^-1 to 10
^{It is 10} Ω · cm.

Further, in order to grasp the effective amount of charged conductive particles in charging, it is more important to adjust the coverage of the conductive particles. Since the charged conductive 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 important to keep the coverage of the charged conductive particles within the range of 0.2 to 1. Become. Further, by quantitatively analyzing the amount of zinc in the conductive particles and the amount of iron in the magnetic toner by the fluorescent X-ray method,
The amount of conductive particles present can also be measured.

As described above, it is more preferable that the conductive particles be positively charged, and more conductive particles will be present in the dark potential portion on the photosensitive member. The amount of conductive particles supplied to the elastic charging member is such that the conductive particles once transferred to the dark potential portion of the photoconductor remain on the photoconductor without being transferred to the transfer target in the transfer process, and are directly supplied to the elastic charging member. Is ideal. Therefore, by setting the electrostatic capacity of the electrophotographic photosensitive member within the range specified by the present invention, the amount of charges in the dark potential portion of the photosensitive member increases, and the Coulomb force acting between the conductive particles increases, The amount of conductive particles transferred from the photoconductor to the transfer target decreases, and as a result, the amount of conductive particles supplied to the elastic charging member increases, and the charging becomes more stable.

(5) Electrophotographic Photosensitive Member The electrostatic capacitance C of the electrophotographic photosensitive member of the present invention is generally represented by the following formula (16).

C = εε ₀ × S / d Formula (16) ε ₀ : permittivity of free space, ε: relative permittivity S: unit area, d: distance between electrodes

In the present invention, the unit area of S is assumed to be a constant area of 1 cm ² and can be treated as a constant, and ε ₀ is also a constant. Therefore, the value is determined by the relative dielectric constant of the film and the film thickness.
The electrophotographic photosensitive member used in the present invention has at least two layers such as a photosensitive layer and a charge injection layer, and the electrostatic capacity of the electrophotographic photosensitive member is the sum of the electrostatic capacities of the respective films. Become. The electrophotographic photoreceptor used in the present invention has a charge injection blocking layer, a charge generation layer, a charge transport layer and a charge injection layer formed in this order on an aluminum support, and the support can be treated as an electrode.
The sum when the capacitances of the other layers are connected in series will appear in the measured values. A sample for measuring the electrostatic capacity is cut out in a form including a support in a size that can be installed in a measuring instrument of an electrophotographic photosensitive member, and a gold sample is cut on the surface of the electrophotographic photosensitive member, in the present invention, on the charge injection layer. An electrode was formed by sputtering so as to have a size of 1 cm ² to obtain a measurement sample. However, as for the material of the electrode, as long as it has conductivity and can be used as an electrode, the material and the method for forming the electrode are not limited to these, and even if the electrode area is not 1 cm ^2, it is calculated per 1 cm ² . However, it is not limited to this. An impedance measuring device (YH
P 4192A) was slightly modified to measure samples with curvature, and measurement was performed at 1 kHz.
Was used as the measured value. When an electrode having an electrode area of not 1 cm ² was used, it was converted per 1 cm ² and used as the measured value.

The electrophotographic photosensitive member of the present invention is shown in FIG. As the support, a cylindrical one having conductivity was used this time, but the shape may be any one, and examples of the one having conductivity include aluminum, aluminum alloy, copper, zinc, stainless steel, Metal such as vanadium, molybdenum, chromium, titanium, nickel and indium, metal foil such as aluminum and copper laminated on plastic film, aluminum, indium oxide and tin oxide deposited on plastic film, conductive material Examples thereof include metals, plastic films, and paper which are provided alone or together with a binder resin to provide a conductive layer.

The photosensitive layer is composed of a single layer type containing both a charge generating material and a charge transporting material in the same layer, a laminated type having a charge generating layer and a charge transporting layer, and a charge generating layer in a laminated type. There are a forward layer type in which a charge transport layer is formed thereon and an inverse layer type in which a charge generating layer is formed on the charge transport layer, but the present invention is not particularly limited.

As the charge generating material, selenium and selenium-
Inorganic charge generation materials such as tellurium and amorphous silicon; cationic dyes such as pyrylium dyes, thiapyrylium dyes, azurenium dyes, thiacyanine dyes and quinocyanine dyes; squarylium salt pigments; phthalocyanine pigments; anthanthrone pigments , Polybenzquinone pigments such as dibenzpyrenequinone pigments and pyrantrone pigments; indigo pigments; quinacridone pigments; and azo pigments. The charge generation layer can be formed as a vapor deposition layer of these charge generation materials by a vacuum vapor deposition apparatus, or can be formed as a coating layer by applying a coating liquid dispersed or dissolved in a binder resin and drying. .

The binder resin can be selected from a wide range of insulating resins, and can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole and polyvinylpyrene. Preferably, polyvinyl butyral, polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, cellulose resin, urethane resin, epoxy resin, polyvinyl alcohol, etc. Resins of

The binder resin contained in the charge generation layer is preferably 80% by mass or less, and particularly preferably 50% by mass or less, based on the total weight of the charge generation layer. The thickness of the charge generation layer is preferably 5 μm or less, and particularly preferably 0.01 to 1 μm.

The charge transport layer is a polycyclic aromatic compound having a structure such as biphenylene, anthracene, pyrene and phenanthrene in the main chain or side chain; nitrogen-containing ring compound such as indole, carbazole, oxadiazole and pyrazoline; hydrazone compound , An enamine compound, a styryl compound, an arylamine compound, a carbazole compound, and a benzidine compound are applied to a coating solution in which a charge-transporting material is dissolved in a binder resin, followed by drying.

Here, the selection of the charge transport material is largely related to the hole mobility of the photoconductor, and among the above compounds, the styryl compound, the arylamine compound, the hydrazone compound and the benzidine compound are preferable.

In selecting these charge-transporting materials, it is not enough to obtain the desired hole mobility under the conditions for producing an ordinary electrophotographic photosensitive member. The electrophotographic photosensitive member of the present invention is characterized in that a charge injection layer is provided on the photosensitive layer. However, due to factors such as heat and light history in the step of providing the charge injection layer, it is possible to use a general photosensitive material. The hole mobility tends to be lower than that of the body. Therefore, in selecting the charge transport material used in the electrophotographic photoreceptor of the present invention, it is necessary to consider stability, particularly heat resistance and robustness.

As a result of intensive studies by the present inventor, among the charge-transporting materials exemplified above, the styryl compound, the arylamine compound and the benzidine compound are particularly stable to the thermal history, and therefore, when the charge injection layer is provided. It was found that the heat treatment does not cause a remarkable decrease in hole mobility.

Further, these charge transport materials may be modified with various substituents for the purpose of controlling solubility, oxidation potential and the like. In this case, although the alkoxy group and the hydroxy group are effective for the purpose of improving the solubility and decreasing the oxidation electrons, the hole mobility is often reduced in many cases. On the contrary, since the alkyl group and the aryl group have a tendency not only to control the solubility and the oxidation potential but also to increase the hole mobility, they can be preferably used as the photosensitive material in the present invention.

As the binder resin, polyarylate, polysulfone, polyamide, acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenol resin, epoxy resin, polyester resin, alkyd resin, polycarbonate resin, polyurethane, Alternatively, copolymers thereof such as styrene-butadiene copolymer, styrene-acrylonitrile copolymer and styrene-maleic acid copolymer may be mentioned. In addition to such insulating polymers, organic photoconductive polymers such as polyvinylcarbazole, polyvinylanthracene and polyvinylpyrene can also be used. Among these binder resins, polycarbonate, polyarylate and polystyrene-containing resins are particularly preferable from the viewpoint of hole mobility.

Regarding the ratio of the binder resin and the charge transport material, the charge transport material can be used in the range of about 10 to 500 parts by mass per 100 parts by mass of the binder resin. To obtain sufficient hole mobility in the electrophotographic process of the present invention, depending on the types of the binder resin and the charge transport material, 40 parts or more of the charge transport material should be added per 100 parts by weight of the binder resin. preferable.

When the photosensitive layer is a single layer type, the photosensitive layer is prepared by coating a solution in which the above-mentioned charge generating material and charge transporting material are dispersed and dissolved in the above-mentioned binder resin on a support and drying. Can be formed.

In the present invention, an undercoat layer having a barrier function and an adhesive function may be provided between the support and the photosensitive layer. As the material of the undercoat layer, polyvinyl alcohol,
Examples thereof include polyethylene oxide, nitrocellulose, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, alcohol-soluble amide, polyamide, polyurethane, casein, glue and gelatin.
The undercoat layer can be formed by applying a solution prepared by dissolving these materials in a suitable solvent onto a support and drying. The film thickness is preferably 5 μm or less, and particularly preferably 0.2 μm to 3 μm.

When the exposure is a laser beam, it is preferable to provide a conductive layer between the undercoat layer and the support in order to prevent interference fringes. The conductive layer can be formed by applying a solution in which a conductive powder such as carbon black and metal particles is dispersed in a binder resin onto a support and then drying the solution. The thickness of the conductive layer is preferably 5 to 40 μm, and particularly preferably 5 to 30 μm.

The various layers described above are formed by a coating method such as a dip coating method, a spray coating method, a beam coating method, a spinner coating method, a roller coating method, a Meyer bar coating method and a blade coating method using an appropriate organic solvent. can do.

Next, the charge injection layer of the electrophotographic photosensitive member of the present invention will be described.

In the present invention, examples of the conductive particles used in the charge injection layer include metals, metal oxides, carbon black and the like. As the metal, aluminum,
Examples thereof include zinc, copper, chromium, nickel, silver and stainless steel, or those obtained by vapor-depositing these metals on the surface of plastic particles. As the metal oxide, zinc oxide,
Titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin-doped indium oxide,
Examples thereof include tin oxide doped with antimony and 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 average particle size of the conductive particles used in the present invention is preferably 0.3 μm or less, and particularly preferably 0.1 μm or less, from the viewpoint of transparency of the charge injection layer. In addition, 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 present invention are at least one of fluorine atom-containing resin particles, silicone particles, silicon particles and alumina particles, but fluorine atom-containing resin particles are preferable. Fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluoroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodichloroethylene resin and copolymers thereof. It is preferable to appropriately select one kind or two or more kinds from the combination, and especially a tetrafluoroethylene resin and a vinylidene fluoride resin are preferable.
The molecular weight of the resin particles and the particle size of the particles can be appropriately selected and are not particularly limited. Also, the inorganic particles such as silicon particles and alumina particles alone may not work as lubricity particles, but by dispersing and adding these, the surface roughness of the surface of the charge injection layer increases,
It has been known by the present inventors that the number of contact points is reduced with respect to the one in contact with the surface of the photoreceptor, and as a result, the lubricity of the charge injection layer is increased. The term "lubricant particles" as used herein includes particles that impart lubricity.

The fluorine atom-containing resin particles together with the conductive particles should be prevented from aggregating with each other in the resin solution.
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 where there is no fluorine atom-containing compound. Has improved significantly. 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.

[0111]

[Table 1]

[0112]

[Table 2]

[0113]

[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,
A surface treatment agent is attached to the surface of the conductive particles. As a dispersing method, a usual dispersing means such as a ball mill or a sand mill can be used. Next, the solvent may be removed from this dispersion solution and fixed on the surface of the conductive particles. 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% by mass, and particularly preferably 1 to 50% by mass with respect to the total mass of the surface-treated conductive particles. Mass% is preferred.

As described above, 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, the fluorine atom-containing resin particles can be dispersed. It is possible to form a charge injection layer that is stable and has excellent slipperiness and releasability. However, due to recent progress in colorization, higher image quality, and higher stability, there has been a demand for more environmental stability, and the protective layer has also required more environmental stability. The amount of surface treatment is measured from the amount of change in mass after heating the surface-treated metal or metal oxide particles at 505 ° C. using TG-DTA, or at 500 ° C./2 by the ignition loss method using a crucible. It can be obtained from the amount of change in mass over time.

The binder resin for the charge injection layer used in the present invention has a small environmental change in resistance of the charge injection layer,
A curable phenol resin was used in terms of hard surface hardness, excellent abrasion resistance, dispersibility of fine particles, and stability after dispersion. In consideration of productivity, thermosetting resol type phenol resin is more preferable.

Further, in the present invention, in order to form a charge injection layer having more environmental stability, a siloxane compound represented by the following formula (1) is added at the time of dispersing conductive particles,
Alternatively, by mixing the conductive particles that have been surface-treated in advance, it was possible to obtain a charge injection layer that was more excellent in environmental stability.

[0119]

[Chemical 4]

In the formula, A is a hydrogen atom or a methyl group,
Moreover, the ratio of hydrogen atoms in all A is 0.1 to 50.
%, N is an integer of 0 or more.

A coating liquid in which this siloxane compound is dispersed is added, or conductive metal oxide fine particles surface-treated with this are dispersed together with a solvent, and a binder is further added to form secondary particles of dispersed particles. In addition, a coating liquid that was stable and dispersed well over time was obtained, and the charge injection layer formed from this coating liquid was highly transparent, and a film having particularly excellent environmental resistance was obtained. Further, when the resin used for the charge injection layer is a curable phenol resin, it may be seen that streaky unevenness or cells are formed depending on the film thickness of the charge injection layer or other conditions. By adding the compound or using the conductive fine particles surface-treated, it was possible to suppress the formation of streaky unevenness and cells, and there was an unexpected effect of the leveling agent.

The molecular weight of the siloxane compound represented by the general formula (1) is not particularly limited, but when the surface treatment is carried out, it is preferable that the viscosity is not too high because of its easiness, and the weight average molecular weight is A few hundred to tens of thousands is suitable.

There are two types of surface treatment methods, wet type and dry type. In the wet method, the conductive metal oxide particles are dispersed in a solvent with a siloxane compound represented by the general formula (1), and the siloxane compound is attached to the surface of the fine particles. As a dispersing means, a general dispersing means such as a ball mill or a sand mill can be used. Next, this dispersion solution is fixed to the surface of the conductive metal oxide fine particles. In this heat treatment, the Si—H bond in siloxane undergoes oxidation of hydrogen atoms due to oxygen in the air during the heat treatment process to form a new siloxane bond. As a result, siloxane develops into a three-dimensional structure, and the surface of the conductive metal oxide fine particles is covered with this network structure. In this way, the surface treatment is completed by fixing the siloxane compound to the surface of the conductive metal oxide fine particles, but the fine particles after the treatment may be subjected to a crushing treatment, if necessary. In the dry treatment, the siloxane compound is attached to the surface of the fine particles by mixing the siloxane compound and the conductive metal oxide fine particles without using a solvent and kneading. After that, the surface treatment is completed by performing heat treatment or pulverization treatment as in the wet treatment.

The ratio of the siloxane compound to the conductive metal oxide fine particles in the present invention depends on the particle size of the fine particles, the ratio of methyl groups to hydrogen atoms in siloxane, and the like.
1 to 50 mass% is preferable, and 3 to 40 mass% is particularly preferable.

The binder resin for the charge injection layer used in the present invention is preferably a curable resin, and particularly preferably an acrylic resin, an epoxy resin, a polyurethane resin, or a siloxane resin. Above all, it is preferable to use the phenol resin because the environmental change of the resistance of the charge injection layer is small. Furthermore, it is more preferable to use a curable phenol resin, particularly a thermosetting resol type phenol resin, from the viewpoints of hard surface hardness, excellent abrasion resistance, dispersibility of fine particles, and excellent stability after dispersion. preferable.

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, monomers of trimethylolphenols, and mixtures thereof, or those obtained by oligomerizing them, by reacting these phenols with aldehydes under an alkaline catalyst, and Make a mixture of monomers and oligomers. Of these, relatively large molecules in which the structural units of the molecule are repeated 2 to 20 are oligomers and 1
One is a monomer.

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

The phenol resin used in the charge injection layer in the present invention is curable, and more preferably thermosetting, so that it is usually cured in a hot air drying oven after being coated on the photosensitive layer. The curing temperature at this time is 100 to 20.
The temperature is preferably 0 ° C., and particularly preferably 120 to 180 ° 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 ratio of the resin to the conductive particles is a value that directly determines the resistance of the charge injection layer, and the volume resistance of the charge injection layer that can be stably charged by injection charging is 10 ¹⁰ to 10 ¹⁵ Ω · c.
Set it so that it falls within the range of m. Preferably 10 ^10-
It is 10 ¹⁴ Ω · cm. Since the film strength becomes weaker as the amount of conductive particles increases, it is preferable to reduce the amount of conductive particles within a range where the resistance and residual potential of the protective layer are allowable.

The thickness d _IN of the charge injection layer is 0.5 μm ≦ d
It can be used in the range of _IN <10 μm. The charge injection layer keeps the flow of charges by the conductive material, but generally, the movement of charges in the film of this form is much slower than the hole mobility in the film containing the charge transport material as exemplified above. Even if the amount of the conductive material is increased and the volume resistance is decreased, the mobility of charges in the photosensitive layer is not reached. Therefore,
When the thickness of the charge injection layer is 10 μm or more, even if the mobility of the photosensitive layer is high, the rate of retention of charges inside the charge injection layer increases, and generation of positive ghost cannot be suppressed. On the other hand, if the thickness of the charge injection layer is less than 0.5 μm, the charge injection layer is abraded by the friction between the charging member and the charge injection layer itself, and the charge injection layer cannot be sufficiently long.

In the present invention, during the charge injection,
Additives such as coupling agents and antioxidants may be added for the purpose of improving dispersibility, binding property, and weather resistance.

Next, a method of measuring the hole mobility of the electrophotographic photosensitive member described above will be described.

The hole mobility is measured by Time of f
It was performed by the light method. The electrophotographic photosensitive member used in the present invention has a charge injection blocking layer, a charge generation layer, a charge transport layer and a charge injection layer formed in this order on an aluminum support, and the aluminum support can be treated as an earth side electrode. it can. Therefore, the sample for measuring the hole mobility is cut out from the electrophotographic photosensitive member in a form including the support in a size that can be installed in the vacuum evaporation chain bar, and the surface of the electrophotographic photosensitive member, in the present invention, the charge injection layer Gold was semi-transparently vacuum-deposited on the top to obtain a measurement sample. After applying a voltage to this sample, pulsed light irradiation by a laser diode having a wavelength of 680 nm is performed to generate charges from the charge generation layer, and the generated transient current waveform is converted into a high-speed current amplifier (kei).
thley428) and digital oscilloscope (Tek)
It was measured using a Tronix TDS420A). T
For determining the transit time, a method of logarithmically converting the relationship between the current (i) and the time (t) and obtaining it from the bending point of the obtained waveform (Scher-Control)
Method) was used.

In the electrophotographic photosensitive member of this embodiment,
Hole mobility under an electric field of 3 × 10 ⁵ V / cm μ _t (c
m ² / V · sec) must satisfy the following formula (1) and μ _t > 1 × 10 ⁻⁶ cm ² / V · sec formula (1) preferably satisfies the following formula (2) ; Μ _t > 7 × 10 ⁻⁶ cm ² / V · sec formula (2)

Further, a diagram showing current-time characteristics on a real scale when the hole mobility μ _t is obtained, that is, time change of current value flowing in the photosensitive layer after the photosensitive member is irradiated with pulsed light. Are FIGS. 7 and 8. In this case, the peak of the current value is standardized to 1. In FIGS. 7 and 8, the slope of the curve that begins to decay from the peak of the current value corresponds to the charge that first migrates to the surface of the photoconductor and then later migrates to the surface. Compared to FIG. 7, FIG.
Shows a state in which the electric charges are transferred to the surface over a long time. In the photoconductor as shown in FIG. 8, the rate at which the electric charges cannot be completely transferred to the surface becomes high, and as a result, the excess electric charges in the photosensitive layer increase and the ghost becomes worse. As a result of earnestly studying the attenuation of the current value, the slope of the curve that starts the attenuation from the peak of the current value is tangent to the curve passing through this peak: | dI / dt | (se
c ⁻¹ ), and the mobility of holes satisfies the above formula (1), the current value decays | dI / dt
It was found that the ghost can be solved to a better level by satisfying the following expression (3) with | (sec ⁻¹ ); | dI / dt│ ≧ 10 ² sec ⁻¹ expression (3)

<Second Embodiment> Only the changes from the first embodiment will be described.

A means for supplying conductive particles necessary for primary charging is
As shown in FIG. 9, a device for directly coating the elastic charging roller for primary charging was provided. The particles are applied by stirring the charged conductive particles M stored in the housing container 38A with a stirring blade 37A and supplying the conductive elastic particles 2a to the conductive elastic roller 2a. 15 g of the conductive particles M are stored in the housing 38A.

Then, excess charged conductive particles corresponding to the target coating amount are scraped off by the fur brush 39A to apply the charged conductive particles. The control of the coating amount can be adjusted at any time by the rotation speed of the fur brush 39A.

Further, as in the first embodiment, the same operation as in the first embodiment is carried out except that the conductive particles are not mixed in the developing device together with the developer.

In the electrophotographic photosensitive member of this embodiment,
Hole mobility under an electric field of 3 × 10 ⁵ V / cm μ _t (c
m ² / V · sec) must satisfy the following formula (2); μ _t > 7 × 10 ⁻⁶ cm ² / V · sec formula (2)

[0143]

The present invention will be described in detail below with reference to specific examples. In addition, "part" in an Example shows a mass part.

(Example 1) φ30 mm × 260.5 mm
Was used as a support, and a 5% by mass methanol solution of a polyamide resin (trade name: Amilan CM8000, manufactured by Toray) was applied onto 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 represented by the following formula was 9.0.
4 parts of oxytitanium phthalocyanine pigment having strong peaks at °, 14.2 °, 23.9 ° and 27.1 °,

[0146]

[Chemical 5] Polyvinyl butyral resin BX-1 (Sekisui Chemical Co., Ltd.)
2 parts) and 80 parts of cyclohexanone were dispersed in a sand mill using φ1 mm glass beads for about 4 hours. This solution was applied onto the undercoat layer and dried with hot air at 105 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

Then, 9.2 parts of a charge transport material represented by the following formula:

[0148]

[Chemical 6] And bisphenol Z type polycarbonate (trade name: Z
10 parts of (-200, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was dissolved in 100 parts of 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 protective layer, 20 parts of antimony-doped tin oxide ultrafine particles surface-treated with a compound represented by the following formula (treatment amount 7%),

[0150]

[Chemical 7] Methyl hydrogen silicone oil (trade name: KF9
9. 30 parts of antimony-doped tin oxide fine particles surface-treated with Shin-Etsu Silicone Co., Ltd. (20% treatment amount) and 150 parts of ethanol were dispersed in a sand mill for 66 hours, and further, polytetrafluoroethylene fine particles. 20 parts (average particle size 0.18 μm) was added and dispersed for 2 hours. Then, 30 parts of a thermosetting resol type phenol resin {trade name: PL-4804, manufactured by Gunei Chemical Industry Co., Ltd. (containing amine compound)} was dissolved to prepare a preparation liquid.

Using this prepared solution, a film was formed on the above charge transport layer by a dip coating method, dried at a temperature of 145 ° C. for 1 hour, and cured to obtain a charge injection layer. At this time, the film thickness of the obtained charge injection layer was measured using an instantaneous multi-photometry system MCPD-2000 (manufactured by Otsuka Electronics Co., Ltd.) due to light interference because the film thickness was 3.0 μm. Met. Also, the dispersibility of the coating liquid for the charge injection layer is good,
The film surface was a uniform and even surface.

The mobility of the electrophotographic photosensitive member obtained here was 1.8 × 10 ⁻⁵ cm ² / V · sec.

Example 2 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the compound represented by the following formula was used as the charge transport material in Example 1.

[0154]

[Chemical 8]

Example 3 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the compound represented by the following formula was used as the charge transport material in Example 1.

[0156]

[Chemical 9]

Example 4 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the compound represented by the following formula was used as the charge transport material in Example 1.

[0158]

[Chemical 10]

Example 5 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the compound represented by the following formula was used as the charge transport material in Example 1.

[0160]

[Chemical 11]

Example 6 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the compound represented by the following formula was used as the charge transport material.

[0162]

[Chemical 12]

Example 7 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the compound represented by the following formula was used as the charge transport material in Example 1.

[0164]

[Chemical 13]

Example 8 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the compound represented by the following formula was used as the charge transport material in Example 1.

[0166]

[Chemical 14]

Example 9 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the compound represented by the structural unit represented by the following formula was used as the binder resin for the charge transport layer in Example 1.

[0168]

[Chemical 15]

Example 10 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the thickness of the charge injection layer in Example 1 was changed to 1.2 μm.

Example 11 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the thickness of the charge injection layer was changed to 4.2 μm in Example 1 (Example 12) Example 1 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that 9.2 parts of the charge transport material was replaced with 6.0 parts.

(Example 13) Example 12 is the same as Example 12 except that the drying temperature of the charge injection layer is 160 ° C.
An electrophotographic photosensitive member was produced in the same manner as.

Example 14 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge injection layer was changed as follows.

Methylhydroxysiloxane compound (KF
-99, Shin-Etsu Chemical Co., Ltd. surface treatment (treatment amount 8.2)
Mass%) Conductive material: Antimony-containing tin oxide fine particles (trade name T-1, manufactured by Mitsubishi Materials Corporation) 50
Parts by mass, acrylic resin (Kalayad DPHA, manufactured by Nippon Kayaku Co., Ltd.) 23 parts by mass and ethanol 150 parts by mass are dispersed in a sand mill for 66 hours, and further 2 parts by mass of 2-methylthioxanthone as a photopolymerization initiator. It was made to melt and it was set as the charge injection layer coating material. This coating material is applied on the charge transport layer by dip coating to form a film, and 1000 mW with a high pressure mercury lamp.
The surface protection layer was cured by irradiating it with ultraviolet rays at a light intensity of / cm ² for 2 minutes and then dried with hot air at 120 ° C. for 1 hour to form a surface protection layer having a thickness of 3.0 μm. (Example 15) An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the dry curing condition of the charge injection layer was changed to 125 ° C for 20 minutes.

Example 16 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the thickness of the charge injection layer in Example 1 was changed to 0.15 μm.

Example 17 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the thickness of the charge injection layer in Example 1 was changed to 12.0 μm.

Comparative Example 1 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge injection layer was not provided in Example 1.

Comparative Example 2 An electrophotographic photosensitive member was produced in the same manner as in Example 8 except that the dry curing condition of the charge injection layer in Example 8 was changed to 180 ° C. for 2.5 hours.

(Comparative Example 3) An electrophotographic photosensitive member was produced in the same manner as in Example 2 except that 9.2 parts of the charge transport material in Example 2 was changed to 3.5 parts.

(Comparative Example 4) An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport layer was provided as follows. That is, 6.5 parts of the charge transport material represented by the following formula

[0180]

[Chemical 16] And polymethylmethacrylate (trade name: J-899,
10 parts by HOSHIKO CHEMICAL CO., LTD.
Dissolved in 0 parts. This solution was applied onto the charge generation layer and dried in hot air at 105 ° C. for 1 hour to give a film thickness of 20.
A μm charge transport layer was formed.

<Evaluation Test 1> The evaluation of the electrophotographic photosensitive members produced in Examples 1 to 15 and Comparative Examples 1 to 7 was carried out by using a laser jet 4000 manufactured by Hewlett Packard Co.
An actual machine modified from the configuration of the first embodiment shown in FIG. The volume resistance of the conductive particles for primary charging at this time is 1 Ω.
cm, and the amount of conductive particles carried on the elastic charging member at the initial stage of durability was 5 mg / cm ² . The voltage applied to the primary charging member was −700 V only for the DC component. Furthermore, an endurance test of 10,000 sheets of electrophotographic photosensitive member was carried out in an environment of a temperature of 20 ° C. and a humidity of 5%. Also, 3 × 10
^The hole mobility of the electrophotographic photosensitive member was measured under an electric field of ⁵ V / cm. The evaluation results are shown in Table 4.

<Evaluation Test 2> In Evaluation Test 1, the amount of conductive particles loaded on the elastic charging member at the initial stage of durability was 0.1 mg.
The same operation was performed except that the value was changed to / cm ² . The evaluation results are shown in Table 4.

<Evaluation Test 3> In Evaluation Test 1, the conductive particles used for primary charging have a volume resistance of 1 × 10 ¹² Ω · cm.
The procedure was exactly the same, except that The evaluation results are shown in Table 4.

<Evaluation Test 4> In the evaluation test 1, except that the evaluation of the test was performed using a laser jet 4000 manufactured by Hewlett Packard Co., Ltd., which was modified in the configuration of the second embodiment shown in FIG. I went the same way. The evaluation results are shown in Table 5.

<Evaluation Test 5> In Evaluation Test 1, the voltage applied to the elastic member for primary charging was set to A of DC-700V.
The same operation was performed except that the C component was superimposed on Vpp200V. The evaluation results are shown in Table 5.

<Evaluation Test 6> In Strengthening Test 1, the conductive charging particles mixed in the developing device were used without using the elastic charging member for primary charging but using the standard charging member for Laser Jet 4000 manufactured by Hewlett Packard Co. The procedure was exactly the same, except that the developer was removed and replaced with only the developer. However,
The durability test was not conducted because the image quality due to poor charging was extremely poor. The evaluation results are shown in Table 5.

[0187]

[Table 4]

[0188]

[Table 5]

As shown in Tables 4 and 5, Examples 1 to 1
The electrophotographic photosensitive member prepared in No. 17 had a relatively high hole mobility, and when images were formed in the charging process of the present invention, image defects such as positive ghosts due to charge retention and streaks due to charging defects were observed. There wasn't. On the other hand,
In Comparative Example 1, since no charge injection layer was provided on the surface, in the charging system of the present invention, a good image was obtained while the number of images to be printed was extremely small, but the charge in the charging process was It is difficult to inject, especially under low humidity, the required charging potential cannot be obtained, and even in the output in the solid white image mode in which the exposure is not applied, the toner is developed in the low potential part and black streaks occur. Occurred. Furthermore, in Comparative Examples 2, 3 and 4, ghosts occurred because the hole mobility was low and charge retention was likely to occur.

In Example 15, although the initially printed image was good, after the 10,000-sheet durability test, some black streaks were generated in the solid white image. When the surface of the electrophotographic photosensitive member after the durability test was observed, it was found that the provided charge injection layer was obliterated and the lower charge transport layer was exposed. Therefore, when the surface of the charge injection layer of Example 15 was rubbed with a cloth soaked in tetrahydrofuran, a part of the film of the injection layer was dissolved. This phenomenon was not seen in the charge injection layer of the other examples. Therefore, it can be inferred that the cause of the black streak is that the curing condition at the time of forming the charge injection layer is insufficient, the strength of the charge injection layer is weak, and the charging failure occurs in the portion worn in the durability test.

In Example 16, although the initially printed image was good, after the 10,000-sheet durability test, a very slight black streak was partially generated in the solid white image. When the surface of the electrophotographic photosensitive member after the durability test was observed, it was found that the provided charge injection layer was obliterated and the lower charge transport layer was exposed. Therefore, it can be inferred that the cause of the black streaks is that the charge injection layer has an insufficient film thickness, and a slight charging failure occurs in the portion where the charge injection layer is abraded by rubbing against the charging member in the durability test.

In Example 17, although the initially printed image was good, a very slight ghost was generated after the 10,000-sheet durability test. It is considered that this is because the thickness of the charge injection layer was too large and the retention of charges was gradually integrated during the repetition of the electrophotographic process in the durability test.

Evaluation Test 3 is a process in which the resistance of the conductive particles is high and the charging ability by injection is slightly weak, but in that case, the hole mobility of the photosensitive layer does not fall within the range of the formula (2). A slight ghost was observed in Nos. 13 and 13. It was also confirmed that when the hole mobilities are almost the same, the ghost level of the photoconductor having a large current value attenuation | dI / dt | is good.

In Evaluation Test 6, no matter which electrophotographic photosensitive member was used, the conductive particles were removed and the charging member was changed. Therefore, the injection of charges into the charge injection layer (or the surface of the photosensitive member) was performed. The efficiency has dropped extremely. Furthermore, since the applied voltage did not exceed the discharge start voltage, discharge could not occur, and as a result, the surface of the electrophotographic photosensitive member could not be charged to the required potential, making it impossible to establish an electrophotographic process. Met.

[0195]

As described above, according to the present invention,
It is possible to suppress the phenomenon peculiar to the charging process of the present invention in which surplus charges are easily retained inside the photosensitive layer, and as a result, a good image can be stably supplied with almost no image defects such as ghost generation. Further, by using the electrophotographic apparatus using the electrophotographic photosensitive member and the process cartridge, it is possible to stably supply a good image with almost no image defects such as ghost generation.

[Brief description of drawings]

FIG. 1 is a diagram showing a difference between discharge charging and injection charging when only a DC voltage is applied to a charging roller.

FIG. 2 is a diagram showing a difference between discharge charging and injection charging when an AC voltage is superimposed on a DC voltage and a voltage is applied to a charging roller.

FIG. 3 is a diagram showing a schematic configuration in Embodiment 1 of the electrophotographic apparatus of the present invention.

FIG. 4 is a diagram showing a method of measuring resistance of an elastic charging member. (A) Volume resistance measurement, (b) Surface resistance measurement

FIG. 5 is a diagram showing a schematic configuration of an apparatus for measuring a triboelectric charge amount of toner particles.

FIG. 6 is a diagram showing a layer structure of the electrophotographic photosensitive member of the present invention.

FIG. 7 is a diagram showing current-time characteristics of a photosensitive layer having a large current value attenuation | dI / dt |.

FIG. 8 is a diagram showing current-time characteristics of a photosensitive layer having a small current value attenuation | dI / dt |.

FIG. 9 is a diagram showing a schematic configuration of conductive particle supply means in a second embodiment of the electrophotographic apparatus of the present invention.

FIG. 10 is a diagram showing a schematic configuration of a process cartridge having the electrophotographic photosensitive member of the present invention.

[Explanation of symbols] 1 photosensitive drum 2 charging roller 2a core metal 2b Conductive elastic roller M charged conductive particles (charged particles) 3A Charged conductive particle feeder 37A stirring blade 38A housing container 39a fur brush 4 Exposure equipment L exposure light 6 Transfer member 60 1-component magnetic developing device 60a rotating developing sleeve 60b magnet roll 60c regulation blade 60e developing container 60d stirring member 7 Fixing device 9 Process Cartridge 10 guidance means 11 regulation blade n Charging contact part (nip) a Development site b Transcription site 41 Guard electrode 42 Main electrode 43 Insulator drum 61 Protective layer 62 charge transport layer 63 Charge generation layer 64 conductive support 65 Tying layer 66 Undercoat layer S1, S2, S3, S4, S5 Applied power supply

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/02 101 G03G 15/02 101 (72) Inventor Keiko Hiraoka 3-30-2 Shimomaruko, Ota-ku, Tokyo No. Canon Inc. (72) Inventor Yosuke Morikawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Koichi Nakata 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. In-house (72) Inventor Daisuke Tanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F-term (reference) 2H068 AA03 AA05 AA06 AA08 AA21 AA28 AA35 BA61 BB31 BB33 BB34 BB35 BB58 CA06 CA33 FA11 FA19 2H200 GA14 GA16 GA23 GA34 GA46 GA57 GA59 GB22 GB25 GB37 GB50 HA03 HA21 HA28 HB12 HB17 HB22 HB43 HB45 HB46 HB47 HB48 MA03 MA08 MA13 MA14 MA20 MB04 MB05 MC06 MC15 NA02 NA09

Claims (83)

[Claims] 1. A charged particle containing conductive particles having a particle size of 10 μm to 10 nm as a main component and a surface having conductivity and elasticity, and a charged particle carrier for supporting the charged particles, The charged particles have a charging means for contacting the body to be charged and charging the surface of the body to be charged, and the resistance of the particles carried on the carrier is 10 ¹² to 10 ⁻¹ Ω · cm. amount an electrophotographic photosensitive member used in an electrophotographic apparatus is ^{0.1mg / cm 2 ~50mg / cm 2} , at least a photosensitive layer and a charge injection layer electrophotographic photoreceptor on a conductive support, and The hole mobility μ _t (cm ² / V · sec) under an electric field of 3 × 10 ⁵ V / cm has the following formula (1).
An electrophotographic photosensitive member characterized by satisfying: μ _t > 1 × 10 ⁻⁶ cm ² / V · sec formula (1) 2. The hole mobility μ _t (cm ² / V · se)
The electrophotographic photosensitive member according to claim 1, wherein c) satisfies the following formula (2). μ _t > 7 × 10 ⁻⁶ cm ² / V · sec formula (2) 3. An electrophotographic photosensitive member and a primary charging member disposed in contact with the photosensitive member, wherein the primary charging member is an elastic charging member forming a nip portion with the photosensitive member, Conductive particles are present in the nip portion between the primary charging member and the electrophotographic photosensitive member, and a voltage is applied to the photosensitive member from the primary charging member to directly inject charges to the surface of the photosensitive member. In an electrophotographic photosensitive member used in a chargeable electrophotographic apparatus, the electrophotographic photosensitive member has at least a photosensitive layer and a charge injection layer on a conductive support, and 3 × 1
Hole mobility under an electric field of 0 ⁵ V / cm μ _t (cm ² /
V · sec) satisfies the following formula (2): μ _t > 7 × 10 ⁻⁶ cm ² / V · sec formula (2) 4. In the current-time characteristic for obtaining the hole mobility μ _t , the attenuation of the current value | dI / dt | (sec ⁻¹ )
Satisfies the following formula (3):
The electrophotographic photosensitive member according to any one of 3 above. │dI / dt│ ≧ 10 ² sec ^-1 formula (3) 5. The electrophotographic photosensitive member according to claim 1, wherein the film thickness d _IN (μm) of the charge injection layer satisfies the following expression (4). Film thickness: 0.5 μm ≦ d _IN <10 μm Formula (4) 6. The electrophotographic photosensitive member according to claim 1, wherein the charge injection layer contains conductive particles and a binder resin. 7. The electrophotographic photosensitive member according to claim 6, wherein the binder resin used for the charge injection layer is a curable resin. 8. The electrophotographic photosensitive member according to claim 6, wherein the conductive particles used in the charge injection layer are metal or metal oxide particles. 9. The electrophotographic photosensitive member according to claim 1, wherein the charge injection layer contains at least one of a fluorine atom-containing compound and a siloxane compound. 10. The electrophotographic photosensitive member according to claim 1, wherein the charge injection layer contains lubricating particles. 11. The electrophotographic photosensitive member according to claim 10, wherein the lubricating particles are at least one of fluorine atom-containing resin particles, silicone particles, silicon particles and alumina particles. 12. The electrophotographic photosensitive member according to claim 9, wherein the fluorine atom-containing compound is selected from the group consisting of a fluorine-containing silane coupling agent, a fluorine-modified silicone oil and a fluorine-based surfactant. 13. The electrophotographic photosensitive member according to claim 9, wherein the siloxane compound is a siloxane compound represented by the following general formula (1). [Chemical 1] (In the formula, A is a hydrogen atom or a methyl group, and the proportion of hydrogen atoms in all A is in the range of 0.1 to 50%,
(n is a positive integer of 0 or more) 14. The electrophotographic photosensitive member according to claim 7, wherein the curable resin is a phenol resin. 15. The electrophotographic photosensitive member according to claim 14, wherein the phenol resin is a resol type phenol resin. 16. The electrophotographic photosensitive member according to claim 15, wherein the resol-type phenol resin is a resin synthesized by using ammonia or an amine compound. 17. The electrophotographic photosensitive member according to claim 16, wherein the resol-type phenol resin is a resin synthesized by using an amine compound. 18. The electrophotographic photosensitive member according to claim 7, wherein the curable resin is a thermosetting resin that is cured by heat. 19. The electrophotographic photoconductor according to claim 1, wherein the electrophotographic photoconductor is an organic photoconductor. 20. A charging particle comprising conductive particles having a particle diameter of 10 μm to 10 nm as a main component and a surface having conductivity and elasticity, and comprising a charged particle carrying member carrying the charged particles. The charged particles have a charging means for contacting the body to be charged and charging the surface of the body to be charged, and the resistance of the particles carried on the carrier is 10 ¹² to 10 ⁻¹ Ω · cm. in an amount electrophotographic apparatus is ^{0.1mg / cm 2 ~50mg / cm 2} , at least a photosensitive layer and a charge injection layer electrophotographic photoreceptor comprising a該被charged body on a conductive support, and, An electrophotographic apparatus characterized in that a hole mobility μ _t (cm ² / V · sec) under an electric field of 3 × 10 ⁵ V / cm satisfies the following expression (1). μ _t > 1 × 10 ⁻⁶ cm ² / V · sec formula (1) 21. The hole mobility μ _t (cm ² / V · se)
The electrophotographic apparatus according to claim 20, wherein c) satisfies the following expression (2). μ _t > 7 × 10 ⁻⁶ cm ² / V · sec formula (2) 22. An electrophotographic photosensitive member and a primary charging member disposed in contact with the photosensitive member, wherein the primary charging member is an elastic charging member forming a nip portion with the photosensitive member, Conductive particles are present in the nip portion between the primary charging member and the electrophotographic photosensitive member, and by applying a voltage from the primary charging member to the photosensitive member, a charge is directly injected onto the surface of the photosensitive member to be charged. In the electrophotographic apparatus, the electrophotographic photosensitive member has at least a photosensitive layer and a charge injection layer on a conductive support, and has a hole mobility μ _t (cm) under an electric field of 3 × 10 ⁵ V / cm. ² / V · sec) satisfies the following expression (2). μ _t > 7 × 10 ⁻⁶ cm ² / V · sec formula (2) 23. In the current-time characteristic for obtaining the hole mobility μ _t , the attenuation of current value | dI / dt | (sec
23. The electrophotographic apparatus according to claim 20, wherein ⁻¹ ) satisfies the following expression (3). │dI / dt│ ≧ 10 ² (sec ^-1 ) Equation (3) 24. The electrophotographic apparatus according to claim 20, wherein a film thickness d _IN (μm) of the charge injection layer satisfies the following expression (4). Film thickness: 0.5 μm ≦ d _IN <10 μm Formula (4) 25. The electrophotographic apparatus according to claim 20, wherein the charge injection layer contains conductive particles and a binder resin. 26. The electrophotographic apparatus according to claim 25, wherein the binder resin used for the charge injection layer is a curable resin. 27. The electrophotographic apparatus according to claim 25, wherein the conductive resin used for the charge injection layer is metal or metal oxide particles. 28. The electrophotographic apparatus according to claim 20, wherein the charge injection layer contains at least one of a fluorine atom-containing compound and a siloxane compound. 29. The electrophotographic apparatus according to claim 20, wherein the charge injection layer contains lubricating particles. 30. The electrophotographic apparatus according to claim 29, wherein the lubricating particles are at least one of fluorine atom-containing resin particles, silicone particles, silicon particles and alumina particles. 31. The electrophotographic apparatus according to claim 28, wherein the fluorine atom-containing compound is selected from the group consisting of a fluorine-containing silane coupling agent, a fluorine-modified silicone oil and a fluorine-based surfactant. 32. The siloxane compound is represented by the following formula (1):
29. The electrophotographic apparatus according to claim 28, which is a siloxane compound represented by: [Chemical 2] (In the formula, A is a hydrogen atom or a methyl group, and the proportion of hydrogen atoms in all A is in the range of 0.1 to 50%,
(n is a positive integer of 0 or more) 33. The electrophotographic apparatus according to claim 26, wherein the curable resin is a phenol resin. 34. The electrophotographic apparatus according to claim 33, wherein the phenol resin is a resol type phenol resin. 35. The electrophotographic apparatus according to claim 34, wherein the resol-type phenol resin is a resin synthesized using ammonia or an amine compound. 36. The electrophotographic apparatus according to claim 35, wherein the resol-type phenol resin is a resin synthesized by using an amine compound. 37. The electrophotographic apparatus according to claim 26, wherein the curable resin is a thermosetting resin that is cured by heat. 38. The surface of the photoconductor is charged by applying only the DC voltage Vdc (V) to the photoconductor from the primary charging member used for the primary charging means, and the DC voltage Vdc (is applied to the primary charging member. 25. The electrophotographic apparatus according to claim 20, wherein the relational expression between V) and the photoconductor dark potential Vd (V) satisfies the following expression (5). | Vdc | − | Vd | ≦ | Vth / 2 | (5) Here, Vth (discharge start voltage) = (7737.7 × D) ^1/2 +
312 + 6.2 × D D = d _SUM (sum of photosensitive layer thickness d _PC and charge injection layer thickness d _IN / μm) / K (relative permittivity of photosensitive layer) 39. A peak-to-peak voltage Vpp (V) of the alternating voltage when the alternating voltage Vac (V) is superimposed on the DC voltage Vdc (V) on the photoconductor from the primary charging member used in the primary charging means. ) Satisfies the following formula (6): Vpp <2 × Vth formula (6) Further, the applied voltage Vdc (V) to the primary charging member, Vpp
25. The electrophotographic apparatus according to claim 20, wherein the relationship between (V) and the photoconductor dark potential Vd (V) satisfies the formula (5) and the following formula (7). | Vdc |-| Vd | ≤ | Vth / 2 | Formula (5) | Vd |> | Vpp / 2 | + | Vdc |-| Vth | Formula (7) 40. The electrophotographic apparatus according to claim 20, further comprising means for supplying charged conductive particles used for the primary charging means. 41. The electrophotographic apparatus according to claim 40, wherein the electrically conductive charged particle supplying means used for the primary charging means directly coats the charging member. 42. The electrophotographic apparatus according to claim 40, wherein the charged particle supplying means used for the primary charging means directly coats the electrophotographic photosensitive member. 43. When the charged particle supplying means used for the primary charging means stores charged particles together with a developer in the developing means, transfers the charged particles onto the photoconductor, and is transferred to a recording medium,
41. The electrophotographic apparatus according to claim 40, wherein a part of the electrophotographic apparatus is not transferred and remains on the photoconductor and is supplied to the charging unit. 44. The electrophotographic apparatus according to claim 40, wherein the conductive particles, which are the charged particles used for the primary charging means, have a volume resistivity of 1 × 10 ¹⁰ Ω · cm or less. 45. The conductive particles used in the primary charging means have a particle size of 10 nm or more and one pixel or less.
The electrophotographic apparatus according to item 0. 46. The electrophotographic apparatus according to claim 40, wherein the charging member used for the primary charging means rotates in a counter direction with respect to the electrophotographic photosensitive member. 47. The electrophotographic apparatus according to claim 20, wherein a cleaning unit is not provided between the transfer process and the primary charging process. 48. The electrophotographic apparatus according to claim 40, wherein the electrically conductive charged particles used for the primary charging means are positively charged. 49. The electrophotographic apparatus according to claim 20, wherein the charged conductive particles are positively charged with respect to the iron powder carrier. 50. When the conductive particles used for the primary charging means are stored in a developing means together with a developer and transferred onto the photoconductor and transferred to a recording medium, a part of the photoconductor is not transferred. 44. The electrophotographic apparatus according to claim 43, wherein in the charging means remaining on the upper surface and supplied to the charging device, the conductive particles are positively charged in the developing device. 51. The electrophotographic apparatus according to claim 20, wherein the electrophotographic photosensitive member is an organic photoconductor. 52. A charged particle carrier, which comprises conductive particles having a particle size of 10 μm to 10 nm as a main component and a surface having conductivity and elasticity, and which carries the charged particles. The charged particles have a charging means for contacting the body to be charged and charging the surface of the body to be charged, and the resistance of the particles carried on the carrier is 10 ¹² to 10 ⁻¹ Ω · cm. in the process cartridge amount is ^{0.1mg / cm 2 ~50mg / cm 2} , at least a photosensitive layer and a charge injection layer electrophotographic photoreceptor comprising a該被charged body on a conductive support, and 3 A process cartridge characterized in that a hole mobility μ _t (cm ² / V · sec) under an electric field of × 10 ⁵ V / cm satisfies the following expression (1). μ _t > 1 × 10 ⁻⁶ cm ² / V · sec formula (1) 53. The hole mobility μ _t (cm ² / V · se)
53. The process cartridge according to claim 52, wherein c) satisfies the following expression (2). μ _t > 7 × 10 ⁻⁶ cm ² / V · sec formula (2) 54. An electrophotographic photosensitive member and a primary charging member disposed in contact with the photosensitive member, wherein the primary charging member is an elastic charging member forming a nip portion with the photosensitive member, Conductive particles are present in the nip portion between the primary charging member and the electrophotographic photosensitive member, and a voltage is applied to the photosensitive member from the primary charging member to directly inject charges to the surface of the photosensitive member. In a chargeable process cartridge, the electrophotographic photosensitive member has at least a photosensitive layer and a charge injection layer on a conductive support, and has 3 × 10 ⁵ V / cm.
The hole mobility of under field ^{_{μ t (cm 2 / V ·}} sec)
Satisfying the following formula (2): μ _t > 7 × 10 ⁻⁶ cm ² / V · sec formula (2) 55. In the current-time characteristic for obtaining the hole mobility μ _t , the attenuation of current value | dI / dt | (se
The process cartridge according to any one of claims 52 to 54, wherein c ^-1 ) satisfies the following expression (3). │dI / dt│ ≧ 10 ² (sec ^-1 ) Equation (3) 56. The process cartridge according to claim 52, wherein the film thickness d _IN (μm) of the charge injection layer satisfies the following expression (4). Film thickness: 0.5 μm ≦ d _IN <10 μm Formula (4) 57. The process cartridge according to claim 52, wherein the charge injection layer contains conductive particles and a binder resin. 58. The process cartridge according to claim 57, wherein the binder resin used for the charge injection layer is a curable resin. 59. The process cartridge according to claim 57, wherein the conductive resin used for the charge injection layer is metal or metal oxide particles. 60. The process cartridge according to claim 52, wherein the charge injection layer contains at least one of a fluorine atom-containing compound and a siloxane compound. 61. The process cartridge according to claim 52, wherein the charge injection layer contains lubricating particles. 62. The process cartridge according to claim 61, wherein the lubricating particles are at least one of fluorine atom-containing resin particles, silicone particles, silicon particles, and alumina particles. 63. The process cartridge according to claim 60, wherein the fluorine atom-containing compound is selected from the group consisting of a fluorine-containing silane coupling agent, a fluorine-modified silicone oil and a fluorine-based surfactant. 64. The process cartridge according to claim 60, wherein the siloxane compound is a siloxane compound represented by the following general formula (1). [Chemical 3] (In the formula, A is a hydrogen atom or a methyl group, and the proportion of hydrogen atoms in all A is in the range of 0.1 to 50%,
(n is a positive integer of 0 or more) 65. The process cartridge according to claim 58, wherein the curable resin is a phenol resin. 66. The process cartridge according to claim 65, wherein the phenol resin is a resol type phenol resin. 67. The process cartridge according to claim 66, wherein the resol-type phenol resin is a resin synthesized using ammonia or an amine compound. 68. The process cartridge according to claim 67, wherein the resol-type phenol resin is a resin synthesized by using an amine compound. 69. The process cartridge according to claim 58, wherein the curable resin is a thermosetting resin that is cured by heat. 70. The surface of the photoconductor is charged by applying only the DC voltage Vdc (V) to the photoconductor from the primary charging member used for the primary charging means, and the DC voltage Vdc (Vdc (Vdc) applied to the primary charging member is applied. 57. The process cartridge according to claim 52, wherein a relational expression between V) and the photoconductor dark potential Vd (V) satisfies the following expression (5). | Vdc | − | Vd | ≦ | Vth / 2 | (5) Here, Vth (discharge start voltage) = (7737.7 × D) ^1/2 +
312 + 6.2 × D D = d _SUM (sum of photosensitive layer thickness d _PC and charge injection layer thickness d _IN / μm) / K (relative permittivity of photosensitive layer) 71. A peak-to-peak voltage Vpp (V) of an alternating voltage when an alternating voltage Vac (V) is superimposed on a DC voltage Vdc (V) from the primary charging member used in the primary charging means on the photoconductor. ) Satisfies the following formula (6): Vpp <2 × Vth formula (6) Further, the applied voltage Vdc (V) to the primary charging member, Vpp
57. The process cartridge according to claim 52, wherein the relationship between (V) and the photoconductor dark potential Vd (V) satisfies the equation (5) and the following equation (7). | Vdc |-| Vd | ≤ | Vth / 2 | Formula (5) | Vd |> | Vpp / 2 | + | Vdc |-| Vth | Formula (7) 72. The process cartridge according to claim 52, further comprising means for supplying charged conductive particles used for the primary charging means. 73. The process cartridge according to claim 72, wherein the electrically conductive charged particle supplying means used for the primary charging means directly coats the charging member. 74. The process cartridge according to claim 72, wherein the charged particle supplying means used for the primary charging means directly coats the electrophotographic photosensitive member. 75. The charged particle supplying means used for the primary charging means, when the charged particles are stored in a developing means together with a developer, transferred onto the photosensitive member and transferred to a recording medium, 73. The process cartridge according to claim 72, wherein the toner is not transferred and remains on the photoconductor and is supplied to the charging unit. 76. The process cartridge according to claim 72, wherein the conductive particles, which are the charged particles used for the primary charging means, have a volume resistivity of 1 × 10 ¹⁰ Ω · cm or less. 77. The conductive particles used for the primary charging means have a particle size of 10 nm or more and one pixel or less.
2. The process cartridge according to 2. 78. The process cartridge according to claim 72, wherein the charging member used for the primary charging means rotates in the counter direction with respect to the electrophotographic photosensitive member. 79. The process cartridge according to claim 52, wherein the cleaning cartridge is not provided between the transfer process and the primary charging process. 80. The process cartridge according to claim 72, wherein the electrically conductive charged particles used for the primary charging means are positively charged. 81. The process cartridge according to claim 52, wherein the charged conductive particles are positively charged with respect to the iron powder carrier. 82. When the conductive particles used for the primary charging means are stored in a developing means together with a developer and transferred to the photoconductor and transferred to a recording medium, a part of the photoconductor is not transferred. 76. The process cartridge according to claim 75, wherein in the charging means that remains on the top and is supplied to the charging device, the conductive particles are positively charged in the developing device. 83. The process cartridge according to claim 52, wherein the electrophotographic photoconductor is an organic photoconductor.