JP2003091144A - Electrophotographic device, process cartridge and electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic device capable of obtaining a high- definition image with less ghost by attaining stable toner recycling at any time, as for the electrophotographic device introducing a direct injection electrifying system and having a toner recycling constitution. SOLUTION: As to the electrophotographic device provided with an electrifying means, where the surface of the photoreceptor is electrified by a contact type electrifying means for directly injecting a charge from the contact type electrifying member to the photoreceptor, the contact type electrifying member is constituted of electrifying particles and an electrifying particle carrier, and the electrifying means functions also as a means for carrying the residual toner remaining on the surface of the photoreceptor after a transfer process, normalizing the charge of the residual toner and returning the residual toner with the normalized charge to the surface of the photoreceptor, and a developing means functions also as a means for recovering the residual toner with the normalized charge returned to the surface of the photoreceptor, and the electrophotographic device is constituted so as to recycle the toner, the absolute value of an electrification potential difference between the first and second rounds of the photoreceptor is >5 V and <70 V.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus, a process cartridge and an electrophotographic photosensitive member, and more specifically, an electrophotographic apparatus adopting an injection charging system and a toner recycling structure, and a process for the electrophotographic apparatus. The present invention relates to a cartridge and an electrophotographic photosensitive member.

[0002]

2. Description of the Related Art An electrophotographic apparatus includes an electrophotographic photosensitive member, a charging unit for charging the surface of the electrophotographic photosensitive member, and an exposure for forming an electrostatic latent image on the surface of the electrophotographic photosensitive member charged by the charging unit. Means, developing means for developing the electrostatic latent image formed by the exposing means with toner to form a toner image, and transfer means for transferring the toner image formed by the developing means onto a recording medium such as paper, In general, the toner image transferred to the recording medium by the transfer unit is fixed to the recording medium by a fixing unit.

A corona charging device (corona discharger) was often used as the charging means.

Further, since it has advantages such as low ozone and low electric power as compared with the corona charging device, a contact method for charging the electrophotographic photosensitive member by bringing a charging member to which a voltage is applied into contact with the electrophotographic photosensitive member. The charging means (contact charging means) has also been put to practical use.

As the contact charging means, a conductive charging member such as a roller type, a fur brush type, a magnetic brush type or a blade type is brought into contact with the electrophotographic photosensitive member, and this charging member (hereinafter referred to as a contact charging member). In general, a contact charging device for charging a surface of an electrophotographic photosensitive member to a predetermined polarity and potential by applying a predetermined charging bias to (1).

The charging mechanism of the contact charging means includes two types of charging mechanism, a discharge charging mechanism and a direct injection charging mechanism, and each characteristic appears depending on which one is dominant.

First, the discharge charging mechanism is a mechanism in which the surface of the electrophotographic photosensitive member is charged by a discharge phenomenon that occurs in a minute gap between the contact charging member and the electrophotographic photosensitive member.

In discharge charging, since the contact charging member and the electrophotographic photosensitive member have a constant discharge threshold, it is necessary to apply a voltage higher than the charging potential to the contact charging member. Further, although the amount of generation is much smaller than that of a corona charger, it is in principle inevitable that a discharge product is generated, so that the harmful effect of active ions such as ozone cannot be completely eliminated.

On the other hand, the direct injection charging mechanism is disclosed in JP-A-6-3.
This is a mechanism proposed in Japanese Laid-Open Patent Application No. 921 and the like, in which charges are directly injected from the contact charging member to the electrophotographic photosensitive member to charge the surface of the electrophotographic photosensitive member. More specifically, a voltage is applied to the contact charging member, and charges are injected into the charge holding portion of the electrophotographic photosensitive member such as the trap level on the surface of the electrophotographic photosensitive member or conductive particles in the charge injection layer. This is a mechanism for charging the surface of the electrophotographic photosensitive member.

The charging means utilizing the direct injection charging mechanism (direct injection charging means) is such that the contact charging member comes into contact with the surface of the electrophotographic photosensitive member and does not depend on the discharge phenomenon, that is, the discharge mechanism is basically used. Instead, it is a charging means for directly injecting charges to the surface of the electrophotographic photosensitive member.

Therefore, by using the direct injection charging means, the electrophotographic photosensitive member can be charged to a potential corresponding to the applied voltage even if the applied voltage to the contact charging member is less than the discharge threshold value. In other words, since the discharge phenomenon is not dominant, the applied voltage to the contact charging member required for charging is
Only the desired charging potential of the electrophotographic photosensitive member surface.

Further, since no active ions are generated,
The adverse effect of generation of discharge products such as ozone does not occur.

The one using a charging brush or a charging magnetic brush as the contact charging member is expensive, and the one using a magnetic brush may cause the charging carrier to leak from the charging sleeve in the electrophotographic process. In many cases, a roller-type contact charging member (charging roller) is preferably used.

However, it is difficult to carry out direct injection charging with a simple structure using a charging roller or a brush, and image fogging (a white background portion is developed in the case of reversal development) and uneven charging due to absolute charging failure. There may be such cases.

Therefore, the charging means is provided with a contact charging member that comes into contact with the surface of the electrophotographic photosensitive member, and charges the surface of the electrophotographic photosensitive member by directly injecting electric charges from the contact charging member into the electrophotographic photosensitive member. The following are newly proposed as the direct injection charging means.

The contact charging member provided in the charging means is a member having charged particles that come into contact with the electrophotographic photosensitive member and a charged particle carrier that carries the charged particles and has conductivity and elasticity on the surface. It is a direct injection charging means.

As a result, sufficient contact property can be obtained in direct injection charging, and uniform charging can be achieved.

Further, in the electrophotographic apparatus adopting the above-mentioned direct injection charging means, the charging means further carries the residual toner remaining on the surface of the electrophotographic photosensitive member after the transfer by the transfer means, and charges the residual toner. Normalization (primary collection)
Then, the developing means also serves as means for returning the residual toner whose electric charge is normalized to the surface of the electrophotographic photosensitive member, and the developing means for collecting the residual toner whose electric charge is normalized by the charging means and returned to the surface of the electrophotographic photosensitive member. By also functioning as an electrophotographic device, the toner recycling structure can be obtained.

In order to prevent uneven charging of the contact charging device and to perform stable and uniform charging, a structure in which powder is applied to the contact surface of the charging member with the electrophotographic photosensitive member surface is disclosed in Japanese Patent Publication No. 7-99.
Although it is disclosed in Japanese Laid-Open Patent Publication No. 442, the generation of ozone products is smaller than that of a corona charger such as a scorotron, but the principle of charging is mainly corona charging due to discharge, and more particularly, more stable charging uniformity. In order to obtain the voltage, a voltage in which an AC voltage is superimposed on a DC voltage is applied, so that the discharge products are still abundant.

[0020]

However, the direct injection charging means is adopted as means for charging the electrophotographic photosensitive member,
In addition, in an electrophotographic apparatus having a toner recycling structure, the toner temporarily collected by the charging means has a charge amount of the same polarity as the voltage applied to the charging means, and the potential difference between the toner and the surface of the electrophotographic photosensitive member causes electrophotographic exposure. Since it is returned to the body surface, depending on the degree of achievement of toner recycling,
Toner may be excessively accumulated in the charging means due to repeated use and the electrophotographic photosensitive member may be damaged. On the other hand, even if toner recycling is achieved, an image defect such as a ghost may occur from the beginning.

[0021]

As a result of earnest studies, the inventors of the present invention have found that the efficiency of toner recycling and the prevention of ghost are compatible with each other by the difference in the charging potential between the first and second laps of the electrophotographic photosensitive member. It has been found that (electrostatic potential difference) can be achieved by using an electrophotographic photosensitive member having a specific range.

That is, the residual toner is temporarily collected by the charging means and collected by the developing means by the difference between the voltage applied to the charging means and the developing means and the surface potential on the electrophotographic photosensitive member.

Therefore, if the difference between the charging potentials of the first and second turns of the electrophotographic photosensitive member (charging potential difference) is too small, the difference between the potential of the surface of the electrophotographic photosensitive member and the potential of the charging means is small. The difference between the charge of the residual toner temporarily collected by the charging means and the charge is also small, the residual toner is not properly discharged from the charging means to the surface of the electrophotographic photosensitive member, and the residual toner accumulates on the contact charging member of the charging means. Since it becomes dirty, the charging in the next process is not performed well, causing an image defect,
It may scratch the surface of the electrophotographic photoreceptor.

On the contrary, when the charging potential difference is too large, when used in a developing process (reversal developing system) in which the dark portion potential portion is the non-developing portion and the light portion potential is the developing portion, light is not emitted during pre-printing. The history remains where it hits, and when a full black image or halftone image is taken at the time of the next print, a so-called ghost in which the part that was hit by light at the time of the previous print appears as black or becomes white appears remarkably.

The present invention was derived based on such knowledge.

That is, according to the present invention, an electrophotographic photosensitive member having a photosensitive layer on a support, a charging unit for charging the surface of the electrophotographic photosensitive member, and an electrophotographic photosensitive member surface charged by the charging unit are exposed. To form an electrostatic latent image by means of an exposing means, a developing means for developing the electrostatic latent image formed by the exposing means with a toner to form a toner image, and a toner image formed by the developing means. An electrophotographic apparatus, comprising: a transfer unit that transfers the image onto a body; and a fixing unit that fixes the toner image transferred onto the recording medium by the transfer unit onto the recording medium, wherein the charging unit includes the electrophotographic apparatus. A means for charging the surface of the electrophotographic photosensitive member by directly injecting an electric charge from the contact charging member to the electrophotographic photosensitive member, which comprises a contact charging member contacting the surface of the photosensitive member, wherein the contact charging member is The electrophotographic photosensitive An electrophotographic apparatus, which is a member having a charged particle that comes into contact with a charged particle and a charged particle carrying member that carries the charged particle and has conductivity and elasticity on the surface, wherein the charging means is provided after transfer by the transfer means. The developing means also serves as means for carrying the residual toner remaining on the surface of the electrophotographic photosensitive member, normalizing the electric charge of the residual toner, and returning the residual toner whose electric charge is normalized to the surface of the electrophotographic photosensitive member. In an electrophotographic apparatus having a toner recycling structure, which doubles as a means for recovering the residual toner whose electric charge is normalized by the charging means and returned to the surface of the electrophotographic photoreceptor, the first and second laps of the electrophotographic photoreceptor The electrophotographic apparatus is characterized in that the absolute value of the difference in charging potential (charging potential difference) is larger than 5V and smaller than 70V.

The present invention also provides an electrophotographic photoreceptor having a photosensitive layer on a support, charging means for charging the surface of the electrophotographic photoreceptor, and after charging the surface of the electrophotographic photoreceptor by the charging means. Developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member by the exposing means with toner to form a toner image, and the toner image formed by the developing means is transferred to a recording medium. A process cartridge that integrally supports a transfer unit and a fixing unit that fixes the toner image transferred onto the recording medium by the transfer unit onto the recording medium, and is detachable from the main body of the electrophotographic apparatus. The charging means is provided with a contact charging member that comes into contact with the surface of the electrophotographic photosensitive member, and means for charging the surface of the electrophotographic photosensitive member by directly injecting an electric charge from the contact charging member to the electrophotographic photosensitive member. Yes, The tactile charging member is a process cartridge which is a member having charged particles that come into contact with the electrophotographic photosensitive member and a charged particle carrier that carries the charged particles and has conductivity and elasticity on the surface. However, the toner image formed on the surface of the electrophotographic photosensitive member by the developing unit carries the residual toner remaining on the surface of the electrophotographic photosensitive member after being transferred to the recording medium by the transfer unit,
The developing means also serves as means for normalizing the electric charge of the residual toner and returning the residual toner whose electric charge is normalized to the surface of the electrophotographic photosensitive member, and the developing means having the electric charge normalized by the charging means. In a process cartridge having a toner recycling structure that also serves as a means for collecting the residual toner returned to the above, the absolute value of the difference in charging potential (charging potential difference) between the first and second rounds of the electrophotographic photosensitive member is 5V or more. Also big 7
It is a process cartridge characterized by being smaller than 0V.

An electrophotographic photosensitive member for the electrophotographic apparatus is also provided.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the absolute value of the difference (charging potential difference) between the charging potentials on the first and second laps of the electrophotographic photosensitive member means that the electrophotographic photosensitive member in a stationary state is rotated once. It is the absolute value of the difference between the charging potential at the time of rotation and the charging potential at the time of continuing the second rotation. Further, the charging potential changes not only by the electrophotographic photosensitive member but also by the charging means, for example, the applied voltage and the size and type of the charged particles, the size of the nip portion formed by the charging means and the photosensitive member, and the like. The charging means at the time of measuring the charging potential must be the same as the charging means of the electrophotographic apparatus for image formation.

As described above, the absolute value of the difference between the charging potentials on the first and second turns of the electrophotographic photosensitive member (charging potential difference) is 5V.
It is necessary to be larger than 70V and smaller than 70V,
More preferably, it is larger than 20V and smaller than 70V.

First, the structure of the electrophotographic apparatus of the present invention will be described.

The electrophotographic apparatus of the present invention is an electrophotographic apparatus which utilizes a transfer type electrophotographic process and employs a direct injection charging system and a toner recycling process. 1 shows an example of a schematic configuration of the electrophotographic apparatus of the present invention, the configuration of the electrophotographic apparatus of the present invention is not limited to this example.

Reference numeral 1 is an electrophotographic photosensitive member, and this electrophotographic photosensitive member 1 is rotationally driven in the direction of the arrow at a constant peripheral speed (= process speed (PS), printing speed).

The charging means 2 has conductive particles (charged particles) M for the charging means, and a charged particle carrier having a medium resistance layer (elastic layer) 2b and a core metal 2a. And a charging contact portion n is formed.

At the charging contact portion n, the charged particle carrying member is rotationally driven in the opposite direction (counter) to the rotating direction of the electrophotographic photosensitive member 1 and contacts the surface of the electrophotographic photosensitive member 1 with a speed difference. To do.

At the time of image formation, a predetermined charging bias is applied to the charging means 2 from the charging bias applying power source S1, so that the peripheral surface of the electrophotographic photosensitive member 1 is directly injected by a predetermined polarity. Contact charging is applied uniformly to the electric potential.

The charged particles M are accumulated together with the toner t in a developing container 60e of the developing means 60, which will be described later, and are supplied to the charging roller via the electrophotographic photosensitive member together with the development of the toner. Further, it may have a charged particle supply member for supplying the charged particles M to the charged particle carrier.

Reference numeral 4 is an exposing means. Examples of the exposing means 4 include a laser beam scanner including a laser diode and a polygon mirror. This laser beam scanner outputs a laser beam whose intensity is modulated corresponding to a time-series digital image signal of desired image information, and scans and exposes the uniformly charged surface of the rotating electrophotographic photosensitive member 1 with the laser beam. . The scanning exposure light L forms an electrostatic latent image on the surface of the rotating electrophotographic photosensitive member 1 corresponding to the target image information.

Reference numeral 60 is a developing means. The electrostatic latent image on the surface of the rotating electrophotographic photosensitive member 1 is developed as a toner image at the developing portion a by the developing means 60. Developing means 6
In the developing container 60e of 0, a mixture tm in which charged particles M are added to the toner t is provided. Reference numeral 60a is a non-magnetic rotary developing sleeve as a developer carrying / conveying member that encloses a magnet roll 60b, and the toner t in the pre-development mixture tm provided in the developing container 60e is conveyed on the rotary developing sleeve 60a. In the process, the regulation blade 60c receives layer thickness regulation and charge application. 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 electrostatic latent image on the electrophotographic photosensitive member is visualized in the developing area a by the bias applied between the sleeve and the electrophotographic photosensitive member.

Reference numeral 6 is a transfer means. Transfer means 6 in the figure
Is a cored bar 6a on which a medium resistance foam layer 6b is formed, and a voltage is applied to the cored bar to perform transfer.

The electrophotographic apparatus of the present invention is a toner recycling process, and the residual toner remaining on the surface of the electrophotographic photosensitive member 1 after image transfer is transferred to the charging means which counter-rotates as the electrophotographic photosensitive member 1 rotates. Temporarily collected,
The toner charge that has been reversed around the outer circumference is normalized, and is sequentially discharged to the electrophotographic photosensitive member to reach the developing portion a, and is recovered and reused in the developing device 60 by simultaneous cleaning with development. Therefore, it is not always necessary to remove it with a dedicated cleaner (cleaning means).

Reference numeral 7 is a fixing means such as a heat fixing system. The recording medium P that has been fed to the transfer nip portion b and transferred with the toner image on the electrophotographic photosensitive member 1 side is separated from the surface of the rotating electrophotographic photosensitive member 1 and introduced into the fixing unit 7. After the toner image is fixed, the image formed product (print
It is ejected outside the electrophotographic device as a copy).

Further, as shown in FIG. 6, for example, the charging means 2 and the developing means 60 are integrally supported together with the electrophotographic photosensitive member 1 to form a cartridge, which is mounted on the apparatus main body by using guide means such as the rail 10 of the apparatus main body. The process cartridge 9 can be attached and detached. Reference numeral 11 is a regulation blade.

It should be noted that S1, S2, S3, S4 and S5 in FIGS. 1 and 6 and FIGS.

In the drawings, the same reference numerals denote the same members, and the duplicated description will be omitted.

FIG. 5 is a diagram showing a schematic structure of the charged particle supply member of the electrophotographic apparatus of the present invention. 3A is a charged particle supply member, M is a charged particle, 37A is a stirring blade, 38A is a housing container, 39a is a fur brush, and 39b is a regulating blade.

Next, the structures of the charging means and the developing means used in the electrophotographic apparatus of the present invention will be described.

The charged particle carrier of the charging means used in the electrophotographic apparatus of the present invention is a roller in which a medium resistance layer (elastic layer) 2b of rubber or foam is formed on a core metal 2a as shown in FIG. A shape (charging roller) is preferable.

The medium resistance layer (elastic layer) 2b is formulated with a resin such as urethane, a sulfiding agent and a foaming agent, and is formed in a roller shape on the core metal 2a. The surface may be polished to obtain a predetermined surface roughness.

The charged particle carrying member is required to carry charged particles at a high density, and therefore a certain degree of surface roughness is required. The average roughness Ra is preferably 1 μm to 500 μm. 1
If it is less than μm, the surface area for supporting the charged particles is insufficient, and when an insulating material such as toner adheres to the surface layer of the charged particle carrier, the charged particles carried in the periphery should be brought into contact with the electrophotographic photoreceptor. Are no longer possible and the charging performance is reduced. On the other hand, when it exceeds 500 μm, the unevenness on the roller surface reduces the in-plane charging uniformity of the electrophotographic photosensitive member.

To measure the average roughness Ra, the surface shape measuring microscopes VF-7500 and VF7510 manufactured by Keyence Corp. are used with an objective lens of 1250 times to 2500 times, and the shape of the roller surface and Ra are measured without contact. It was

Further, in the direct injection charging method, since the charging does not involve the discharge start voltage, the charging can be performed even when the applied voltage is low, so that the charging roller (= charged particle carrier) has a high resistance. The roller can be composed of a single layer, without the need for

The surface resistance of the charged particle carrier is 10 ⁴ to 1
It is preferably 0 ¹⁰ Ω □. When it exceeds 10 ¹⁰ Ω □, the uniformity in the charged surface is deteriorated, unevenness due to rubbing of the roller appears as streaks in the halftone image, and the image quality may be deteriorated. On the other hand, when it is less than 10 ⁴ Ω □, a peripheral voltage drop may occur due to the drum pinhole.

Further, regarding the volume resistance, 10 ⁴ to 1
It is preferably in the range of 0 ⁷ Ω · cm. 10 ⁴ Ω
If it is less than cm, a voltage drop of the power source may occur due to pinhole leakage. On the other hand, if it exceeds 10 ⁷ Ω · cm, the current required for charging cannot be secured, and the charging voltage may decrease.

The resistance of the charged particle carrying member is measured by the following procedure.

FIG. 2 shows a schematic view of the structure at the time of measurement.

The resistance of the charged particle carrier is 30 m in outer diameter so that a total pressure of 1 kg is applied to the core metal 2a of the charged particle carrier.
An electrode was applied to the insulating drum 43 of m to measure. The electrodes are
The guard electrode 41 was arranged around the main electrode 42, and the measurement was performed with the wiring diagram shown in FIG. The distance between the main electrode and the guard electrode was adjusted to about the thickness of the medium resistance layer (elastic layer) 2b, and the main electrode secured a sufficient width with respect to the guard electrode. In the measurement, +100 V was applied to the main electrode from the power source S4, the currents flowing through the ammeters Av and As were measured, and the volume resistance and the surface resistance were measured, respectively.

In the direct injection charging system, it is important that the charging means functions as a flexible electrode. The charging means of the electrophotographic apparatus of the present invention can be achieved, for example, by adjusting the elastic characteristics of the medium resistance layer (elastic layer) of the charged particle carrier. The Asker C hardness is preferably 15 to 50 degrees, more preferably 25 to 40 degrees. If the hardness is too high, the required amount of penetration cannot be obtained, and the charging contact part n cannot be secured between the electrophotographic photosensitive member and the charging performance in some cases. Further, since the molecular level contact property of the substance cannot be obtained, the contact with the periphery thereof is hindered by the inclusion of foreign matter. On the other hand, if the hardness is too low, the shape irregularity is not stable, so that the contact pressure with the body to be charged may be uneven, and uneven charging may occur. Alternatively, charging failure may occur due to permanent deformation strain of the roller due to long-term storage.

The material of the charging roller is EPDM,
Examples thereof include urethane, NBR, silicone rubber, and rubber materials in which a conductive material 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. After that, molding is performed by adjusting the surface roughness or polishing, if necessary. Further, a structure having a plurality of layers with separated functions is also possible.

As the form of the roller, a porous structure is more preferable. It is also advantageous from a manufacturing point of view that the above-mentioned surface roughness can be obtained at the same time 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 aforementioned roughness can be produced.

On the other hand, as the material of the charged particles M, one or more kinds of conductive inorganic particles such as metal oxides, a mixture of them and an organic substance, or various kinds of those obtained by surface-treating them. Conductive particles can be used. Further, since the charged particles of the present invention do not need to be magnetically restrained,
It does not have to have magnetism.

The resistance of the charged particles depends on the electrophotographic apparatus of the present invention.
Is the charge that transfers and receives charges through charged particles.
Therefore, the resistance is 10¹²Ω · cm or less is preferable,
10 ¹⁰Ω · cm or less is more preferable.

The resistance of the charged particles was measured by the tablet method and normalized. That is, the bottom area is 2.26 cm
Approximately 0.5 g of charged particles was placed in the ^second cylinder, 15 kg of pressure was applied to the upper and lower electrodes, a voltage of 100 V was applied at the same time, the resistance value was measured, and then normalized to calculate the resistance.

The particle size of the charged particles is preferably 10 μm or less in order to obtain high charging efficiency and charging uniformity exceeding the magnetic brush charging. In the present invention, the particle size when the particles form an aggregate is defined as the average particle size of the aggregate.

For the measurement of the particle size, 100 or more particles were extracted from the observation by an electron microscope, the volume particle size distribution was calculated with the maximum chord length in the horizontal direction, and the 50% average particle size was determined.

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

Since the charged particles are used for charging the electrophotographic photosensitive member, it is preferable that the charged particles are close to white or transparent so as not to interfere with latent image exposure. Further, considering that the charged particles are partially transferred from the photoconductor to the recording medium P, colorless or white ones are preferable in color recording. Further, in order to prevent light scattering by particles during image exposure. However, the particle size is preferably equal to or smaller than the constituent pixel size, more preferably equal to or smaller than the toner particle size. The lower limit of the particle diameter is considered to be 10 nm as a particle that can be stably obtained. Furthermore, it is more preferable that the charged particles be positively charged.

Further, when the developing means used in the electrophotographic apparatus of the present invention is a two-component toner, the magnetic carrier spills along with the toner onto the electrophotographic photosensitive member, and is caught by the charging means and scratches the surface of the electrophotographic photosensitive member. It is preferable that the reversal developing means uses a one-component magnetic toner (negative toner) as the toner because it may be attached and is easy to handle.

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

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

The developing bias voltage is preferably a superimposed voltage of DC voltage and AC voltage.

As a result, the electrostatic latent image on the electrophotographic photosensitive member 1 side is reversely developed by the toner t.

The toner is prepared by mixing a binder resin, magnetic particles, and a charge control agent, kneading, pulverizing, and classifying, and further adding charged particles M and a fluidizing agent as external additives. It is made by.

The average particle diameter (D4) of the toner is 5 to 10 μm.
Is preferred.

Next, the method for measuring the charge amount of the toner particles of the present invention will be described with reference to FIG.

Under an environment of temperature 23 ° C./relative humidity 60%, iron powder carrier DSP-138 (19.6 g) and charged particles 0.
4 g of the mixture is placed in a polyethylene bottle with a volume of 50 to 100 ml and shaken by hand 50 times. Then, 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.
do. At this time, the mass of the entire measuring container 92 is measured, and W
₁ (g). Next, in 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 to adjust the air volume control valve 96 to set the pressure of the vacuum gauge 95 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
(Bolt). Here, 98 is a capacitor, and the capacitance is C (μF). In addition, the mass of the entire measurement container after suction is measured to be W ₂ (g). The triboelectric charge amount (μC / g) of this toner is calculated by the following equation.

Triboelectric charge amount (μC / g) = CV / (W ₁ −
W ₂ ) The electrophotographic apparatus of the present invention has a toner recycling structure,
The charging means may be provided with the charged particle supply member, but the configuration without the charged particle supply member is simpler. However, a configuration is adopted in which charged particles are accumulated together with the toner in the developing container of the developing means without supplying the charged particle supply member and are supplied to the charged particle carrier through the electrophotographic photosensitive member together with the development of the toner. In this case, many toners contaminate the surface of the charged particle carrier.

[0080] The toner in order to maintain the electric charge by triboelectric charging on the surface, preferably has a resistivity of more than 10 ^{1 3} Ω · cm as a resistance value.

Therefore, when the charged particle carrier is contaminated with the toner, the resistance of the charged particles carried on the charged particle carrier increases, and the charging performance deteriorates. for example,
Even if the resistance of the charged particles is low, the resistance of the entire powder carried by the charged particle carrier increases due to the mixing of the toner, thereby impairing the charging property. Thus, the supported amount of the charged particles of the charged particle bearing member is preferably from 0.1 to 50 mg / cm ^2, more preferably 0.1 to 10 mg / cm ^2.

Even so, when the component contains a large amount of toner, the charging performance naturally deteriorates. 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 entire powder carried by the charged particle carrier (including contaminants such as toner and paper powder) is measured by the above method, and the value is 10
⁻¹ to 10 ¹² Ω · cm is preferable, and 10
More preferably, it is ⁻¹ to 10 ¹⁰ Ω · cm.

Further, in order to grasp the effective amount of charged particles in charging, it is more important to adjust the ratio (coverage) of how much the charged particles support the charged particles. Becomes If the charged particles are white,
It can be distinguished from the black color of the magnetic toner. The area showing white in observation with a microscope is obtained as an area ratio. If the coverage is 0.1 or less, the charging performance may be insufficient even if the peripheral velocity of the charged particle carrier is increased. Therefore, the coverage of the charged particles is in the range of 0.2 to 1. It is preferable to keep Further, by a fluorescent X-ray method, for example, in the case of a combination of charged particles containing zinc and a toner containing iron, by quantitatively analyzing the amount of zinc in the charged particles and the amount of iron in the toner, It is also possible to measure the amount of charged particles present.

As described above, it is preferable that the charged particles are positively charged, and more of them will be present in the dark potential portion on the photosensitive member. The amount of charged particles supplied to the charged particle carrier is such that the charged particles once transferred to the dark potential part of the photoconductor remain on the photoconductor without being transferred to the recording medium in the transfer step, and the charged particle carrier is as it is. Is ideally supplied to.

Therefore, the first and second cycles of the electrophotographic photosensitive member are performed.
By setting the absolute value of the difference in charging potential on the circumference (charging potential difference) to be larger than 5 V and smaller than 70 V, the amount of charges in the dark potential portion of the electrophotographic photosensitive member increases, and the coulomb that acts between the charged particles and The force is increased, and the amount of charged particles transferred from the electrophotographic photosensitive member to the recording medium is correspondingly reduced.
The amount of conductive particles supplied to the charged particle carrier increases,
The charging becomes more stable.

Next, the structure of the electrophotographic photosensitive member used in the electrophotographic apparatus of the present invention will be described.

The electrophotographic photoreceptor of the present invention is a single layer type photoreceptor having a single layer type photosensitive layer containing a charge generating substance and a charge transporting substance, or a charge generating layer containing a charge generating substance and a charge transporting substance. Either of the laminated photoreceptors having the laminated photosensitive layer having the charge transport layer containing the substance may be used, but the laminated photoreceptor is more preferable from the viewpoint of electrophotographic characteristics.

As an example of the layer structure of the electrophotographic photosensitive member,
As shown in FIG. 4, the charge generation layer 63 is formed on the support 64,
A charge transport layer 62 is sequentially provided, and a charge injection layer 61 is further provided.
Is provided on the outermost surface of the photoconductor. Further, an intermediate layer 66 or the like may be provided between the support 64 and the charge generation layer 63. Further, the conductive layer 65 may be provided on the support.

As the support, it is possible to use a support having conductivity, such as aluminum, aluminum alloy or stainless steel. In addition, aluminum, aluminum alloy, indium oxide-tin oxide alloy or the like having the above-mentioned support having a layer formed by vacuum deposition and plastic, conductive fine particles (for example, carbon black, tin oxide, titanium oxide and silver particles) A support in which plastic or paper is impregnated with a suitable binder, or a plastic having a conductive binder can be used.

A conductive layer may be provided between the support and the photosensitive layer for the purpose of preventing interference fringes and covering scratches on the support. This conductive layer can be formed by dispersing conductive particles such as carbon black or metal particles in a binder resin. Further, it is also effective to add an appropriate amount of silica fine particles in order to suppress interference fringes.
The thickness of the conductive layer is preferably 2 to 40 μm, and 5 to 25 μm.
m is more preferred. Moreover, in order to suppress interference fringes, the surface of the support may be cut, roughened, or anodized.

On the support or the conductive layer, an intermediate layer having a function of adhering the layer and a function of charge barrier may be provided. As the material of the intermediate layer, polyamide, polyvinyl alcohol, polyethylene oxide, ethyl cellulose,
Examples include casein, polyurethane and polyether urethane. These are dissolved in a suitable solvent and applied. The thickness of the intermediate layer is preferably 0.05 μm to 5 μm, more preferably 0.3 to 1.5 μm.

The charge generating substance used in the present invention includes phthalocyanine pigments, azo pigments, indigo pigments, polycyclic quinone pigments, perylene pigments, quinacridone pigments, azurenium salt pigments, pyrylium dyes, thiopyrylium dyes, squarylium dyes, cyanine dyes, Examples include xanthene dyes, quinoneimine dyes, triphenylmethane dyes, styryl dyes, selenium, selenium-tellurium, amorphous silicon, cadmium sulfide and zinc oxide. Among these, phthalocyanine pigments, as a highly sensitive charge generating substance corresponding to the recent digitization of exposure,
Azo pigments are preferable, and among them, phthalocyanine pigments are more preferable.

In the case of a laminated type photoreceptor, the solvent used for the charge generation layer coating material is selected from the solubility and dispersion stability of the resin and charge generation substance used, but as the organic solvent, alcohols, sulfoxides, Ketones, ethers, esters, aliphatic halogenated hydrocarbons, aromatic compounds and the like can be used.

The charge generation layer contains 0.3% of the charge generation material.
It is formed by uniformly dispersing with a binder resin and a solvent in an amount of up to 4 times by a method such as a homogenizer, an ultrasonic wave, a ball mill, a sand mill, an attritor or a roll mill, coating and drying. The thickness of the charge generation layer is preferably 5 μm or less, and particularly preferably 0.01 to 1 μm.

As the charge transport substance, amine compounds,
Known materials such as oxazole compounds and thiazole compounds can be used.

In the case of a laminated type photoreceptor, the charge transport layer is generally formed by dissolving the charge transport substance and the binder resin in a solvent and coating the solution. The mixing ratio of the charge transport material and the binder resin is about 2: 1 to 1: 2. As the solvent, ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, and chlorinated hydrocarbons such as chlorobenzene, chloroform and carbon tetrachloride are used. To be When applying this solution, for example, a coating method such as a dip coating method, a spray coating method and a spinner coating method can be used, and drying is preferably 10 ° C to 200 ° C, more preferably 20 ° C to 150 ° C. The temperature is in the range of 5 minutes to 5 hours, more preferably 10 minutes to 2 hours under blast drying or static drying.

The binder resin used for forming the charge transport layer includes acrylic resin, styrene resin, polyester, polycarbonate resin, polyarylate, polysulfone, polyphenylene oxide, epoxy resin, polyurethane resin, alkyd resin and unsaturated resin. It is selected from known materials such as resins. Particularly preferred resins include polymethylmethacrylate, polystyrene, styrene-acrylonitrile copolymers, polycarbonate resins and diallylphthalate resins. The thickness of the charge transport layer is preferably 5 to 40 μm, particularly 10 to 30
μm is preferred.

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

Further, the electrophotographic photosensitive member of the present invention has a layer structure having a charge injection layer on the photosensitive layer as a surface layer, and the charging means of the electrophotographic apparatus uses a charge from the contact charging member to the charge injection layer. It is preferable that the means for charging the surface of the electrophotographic photosensitive member by directly injecting is obtained because stable chargeability can be secured.

The thickness of the charge injection layer is 0.5 μm to 10 μm.
Is preferred, and particularly preferably 1 μm to 7 μm.

The charge injection layer preferably contains a binder resin and conductive particles. Furthermore, a charge transport material may be contained.

In the case where the charge injection layer is a layer in which conductive particles are dispersed in a binder resin to adjust the resistance, the binder resin is an electrically insulating transparent resin, and the binder resin may change depending on changes in humidity or temperature. Use a resin whose electrical resistance does not change easily. Moreover, since the charge injection layer is also the surface layer of the electrophotographic photosensitive member as described above, it is required from the background that high speed, high durability and high image quality are required in the electrophotographic apparatus such as a copying machine in recent years. It is necessary to use a binder resin having high strength.

The binder resin for the charge injection layer used in the present invention is preferably a curable resin. The curable resin has small fluctuations in the resistance of the charge injection layer under high temperature and high humidity and normal temperature and low humidity environments, has a high surface hardness, is excellent in abrasion resistance, and further, in terms of fine particle dispersibility and stability after dispersion. Is also excellent.

Of these, phenol resins, epoxy resins and siloxane resins are preferable, and among them, phenol resins are more preferable. Further, it is more preferable to use a resol type phenol resin, particularly a thermosetting resol type phenol resin.

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. As aldehydes,
Examples 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. Among them, a relatively large molecule having a repeating structural unit of 2 to 20 is an oligomer, and one is a monomer.

The alkali catalysts used include metal-based alkali compounds, ammonia and amine compounds, and the metal-based alkali compounds include NaOH and KO.
Hydroxides of alkali metals and alkaline earth metals such as H and Ca (OH) ₂ and the like, and amine compounds include, but are not limited to, ammonia, hexamethylenetetramine, trimethylamine, triethylamine and triethanolamine. It is not something that will be done. Ammonia and an amine compound are preferably used in consideration of resistance fluctuations in a high humidity environment, and further, an amine compound is more preferably used in view of solution stability.

When a thermosetting resin which is hardened by heat is used as the binder resin of the charge injection layer, the charge injection layer is usually applied on the photosensitive layer and then cured in a hot air drying oven or the like.
The curing temperature at this time is preferably 100 ° C to 300 ° C, and particularly preferably 120 ° C to 200 ° C.

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

The conductive particles used as the resistance adjusting agent in the charge injection layer include ZnO, TiO _x , SnO ₂ ,
Metal oxides such as In ₂ O ₃ , Sb ₃ O ₂ -containing SnO ₂ , In ₂ O ₃ -containing SnO ₂ , V ₂ O ₅ , MoO ₃ , NiO and CuO, or metal particles are preferable. Two or more kinds of these conductive particles may be mixed. Among these, SnO ₂ and antimony (Sb), or
A solid solution with Sb ₃ O ₂ or SnO ₂ is preferable because it can lower the electric resistance and can make the charge injection layer substantially transparent.

The ratio of the conductive particles to the binder resin is:
It is a value that directly determines the electric resistance of the charge injection layer, and it is preferable to contain conductive particles so that the electric resistance of the charge injection layer is in the range of 10 ⁹ to 10 ¹⁴ Ω · cm.

When the electric resistance exceeds 10 ¹⁴ Ω · cm,
The efficiency of charge injection due to direct injection charging is likely to deteriorate, resulting in poor charging, and the residual potential is likely to increase, resulting in an image with a lot of fog. On the other hand, if it is less than 10 ⁹ Ω · cm, image blurring and reduction in resolution tend to occur.

The film strength of the charge injection layer generally becomes weaker as the amount of the conductive particles increases, so that the amount of the conductive particles is within a range in which the resistance and the residual potential of the charge injection layer are allowable. It is preferable to reduce the amount.

Further, the charge injection layer should be constructed so as not to substantially prevent passage of light used for exposure. If the particle size of the conductive particles dispersed in the binder resin is too large, the charge injection layer becomes opaque, resulting in a decrease in sensitivity and a decrease in image density. The particle diameter of the conductive particles is preferably the wavelength of light used for exposure (0.42 to 0.8 μm) or less,
Furthermore, 1/2 of the wavelength of light used for exposure (0.3 μ
m) or less is preferable, and 0.1 μm or less is particularly preferable.

Here, the particle size means a volume average particle size.

When the conductive particles are contained in the charge injection layer, a surfactant is added or silane coupling is performed for the purpose of improving dispersibility in the binder resin and suppressing resistance fluctuation. It is preferable to surface-treat the conductive particles with an agent, a titanate coupling agent, an isocyanate compound, a siloxane compound or a compound containing a fluorine atom. Among these, a siloxane compound or a fluorine atom-containing compound is preferable as the surface treatment agent for the conductive particles.

The charge injection layer preferably contains lubricating particles. As the lubricating particles, fluorine atom-containing resin particles, silicone particles, silicon particles or alumina particles are more preferable, and fluorine atom-containing particles are more preferable. Resin particles are more preferred. Further, two or more of these may be mixed.

The fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluoroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodichloroethylene resin, and ,
Particles of these copolymers are preferable, and particles of tetrafluoroethylene resin and vinylidene fluoride resin are particularly preferable. One or two or more of these may be appropriately selected and used.

The molecular weight of the resin particles and the particle diameter of the particles can be appropriately selected and are not particularly limited.

Further, although inorganic particles such as silicon particles and alumina particles may not function as lubricating particles as particles alone, by dispersing and adding them, the surface roughness of the charge injection layer becomes large. As a result, the investigation by the present inventors has revealed that the lubricity of the surface of the charge injection layer is increased.

As described above, in the present invention, the term "lubricant particles" means particles that impart lubricity to the layer surface.

The fluorine atom-containing resin particles and the conductive particles are
In order to prevent both particles from aggregating with each other in the binder resin solution, a fluorine atom-containing compound may be added when dispersing the conductive particles, or the surface of the conductive particles may be surface-treated with a fluorine atom-containing compound. You can do it.

By adding a fluorine atom-containing compound or by subjecting the conductive particles to a surface treatment, the conductive particles and the fluorine atom-containing resin particles in the binder resin solution can be compared with those in the case where no fluorine atom-containing compound is used. The dispersibility and dispersion stability of are significantly improved.

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

Examples of the fluorine atom-containing compounds include fluorine-containing silane coupling agents, fluorine-modified silicone oils, fluorine-based surfactants and the like.

Examples of these preferred compounds are shown in Tables 1 to 3, but the present invention is not limited to these compounds.

[0127]

[Table 1]

[0128]

[Table 2]

[0129]

[Table 3]

Further, by adding the siloxane compound to the binder resin solution at the time of dispersing the conductive particles, or by mixing the conductive particles preliminarily surface-treated with the siloxane compound into the binder resin solution, Further, it is possible to obtain a charge injection layer which is more excellent in environmental stability.

As the siloxane compound, a siloxane compound having a structure represented by the following formula is particularly preferable.

[0132]

[Outside 3]

In the above formula (1), A is a hydrogen atom or a methyl group, the ratio of hydrogen atoms to all A is in the range of 0.1 to 50%, and n is an integer of 0 or more.

The siloxane compound is added to the binder resin solution at the time of dispersing the conductive particles, or the conductive particles preliminarily surface-treated with the siloxane compound are mixed with the binder resin solution to obtain dispersed particles. No secondary particles are formed, and a charge injection layer coating solution that is stable and has good dispersibility over time is obtained. Furthermore, the charge injection layer formed using this charge injection layer coating solution is transparent. And a film having particularly high environmental resistance is obtained.

Further, when the resin used for the charge injection layer is a curable phenol resin, there are cases where streaky unevenness or cells are formed depending on the film thickness of the charge injection layer or other conditions. By adding the siloxane compound to the binder resin solution at the time of dispersing the conductive particles, or by mixing the conductive particles that have been surface-treated in advance with the siloxane compound into the binder resin solution,
It is possible to suppress streaky unevenness and formation of cells.

There was also an unexpected effect of the leveling agent.

The molecular weight of the siloxane compound 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 preferably about several hundreds to several tens of thousands. .

There are two types of surface treatment methods, wet type and dry type.

In the wet method, conductive particles and a siloxane compound are dispersed in a solvent, and the siloxane compound is attached to the surface of fine particles.

As a dispersing means, a general dispersing means such as a ball mill or a sand mill can be used.

Next, this dispersion solution is fixed to the surface of the conductive fine particles. In this heat treatment, S in siloxane
Owing to the oxygen in the air, the i—H bond is oxidized by hydrogen in the air to form a new siloxane bond. As a result, siloxane develops into a three-dimensional structure,
The surface of the conductive particles is wrapped with this network structure.

As described above, the surface treatment is completed by fixing the siloxane compound on the surface of the conductive particles, but the fine particles after the treatment may be subjected to a pulverization treatment, if necessary.

In the dry treatment, the siloxane compound is adhered to the surface of the conductive particles by mixing the siloxane compound and the metal and metal oxide particles without using a solvent and kneading.

Thereafter, heat treatment and crushing treatment are performed in the same manner as the wet treatment to complete the surface treatment.

The ratio of the siloxane compound to the conductive particles in the present invention depends on the particle size of the conductive particles, the ratio of methyl groups to hydrogen atoms in siloxane, and the like.
0 mass% is preferable, and 3-40 mass% is especially preferable.

Further, an additive such as an antioxidant may be added to the charge injection layer.

[0147]

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

Examples 1 to 7 and Comparative Examples 1 to 3 described later
Was evaluated using an electrophotographic apparatus (printer) having the following configuration.

The printer used has the structure shown in FIG. 6, that is, a laser printer of the toner injection process (cleanerless system without a cleaning means) of the direct injection charging type using the transfer type electrophotographic process. It is a modified machine of LaserJet 4000 (manufactured by Hewlett-Packard Co.).

The electrophotographic photosensitive member is a rotary drum type negative polarity organic electrophotographic photosensitive member (OPC) having a diameter of 30 mm, and is rotationally driven at a process speed of 110 mm / s.

The applied voltage applied from the charging bias applying power source to the charging means is DC-620V.

The charged particle carrying member was produced by forming a medium resistance layer (elastic layer) of rubber on a core metal having an outer diameter of 6 mm and a longitudinal length of 250 mm (thickness of elastic layer: 3 mm, length of elastic layer: 220 mm). ). Here, the medium resistance layer (elastic layer) is formulated with urethane resin, conductive particles (carbon black), a sulfiding agent, a foaming agent, etc., and is formed into a roller shape on a cored bar, and then the surface is ground to obtain a diameter. A roller having a surface of a porous body having a length of 12 mm and a length of 250 mm was produced.

The electrophotographic photosensitive member is provided with an intrusion amount of 0.3 mm to form a charging contact portion of about 2 mm.
The charging contact portion was formed by pressure-bonding to the electrophotographic photosensitive member so that a total pressure of 1 kg was applied to the cored bar of the charged particle carrying member.

The surface of the charged particle carrying member moves so as to move in the opposite direction to the surface of the electrophotographic photosensitive member at a constant speed.
Drive at 50 rpm.

The surface roughness Ra of the charged particle carrier is 40 μm.
m, and the Asker C hardness is 22 degrees.

The surface resistance of the charged particle carrier is 10 ⁷ Ω □, the volume resistance is 10 ⁶ Ω · cm, and the roller resistance is 10 ⁵ Ω. The roller resistance was measured by applying 100 V to the core of the charged particle carrying member and the support of the electrophotographic photosensitive member in the state where the charging contact portion was formed.

The developing bias voltage is a superimposed voltage of DC voltage and AC voltage, and is a system in which the electrostatic latent image on the electrophotographic photosensitive member is reversely developed by the toner. The average particle diameter (D4) of the toner is 7 μm.

The charged particles have a resistance of 10 ⁶ Ω · c.
m, an average particle diameter of 3 μm, and conductive zinc oxide (white) was used. The resistance was measured by the tablet method, and the resistance was normalized to obtain the resistance. A 0.5 g powder sample was placed in a cylinder with a bottom area of 2.26 cm ² , 15 kg of pressure was applied to the upper and lower electrodes, and a voltage of 100 V was applied at the same time to measure the resistance value and then normalize the resistance. It was calculated.

The charged particles are contained in the developing container together with the toner. The amount of triboelectricity of the charged particles with respect to the iron powder carrier is +5 μC / g.

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

In this electrophotographic apparatus, injection charging is performed by charging the charged particle carrier and the charged particles present in the charging contact portion of the electrophotographic photosensitive member with each other without rubbing the surface of the electrophotographic photosensitive member.

The amount of charged particles carried by the charged particle carrier is 4 m.
g / cm ^2, the rate at which the charged particles are carried on the charged particle bearing member covers the charged particle bearing surface (coverage) is 0.
8

A roller-shaped transfer roller was used as the transfer means, the transfer roller had a resistance value of 5 × 10 ⁸ Ω, and a voltage of +2.0 kV was applied to the core bar to perform transfer.

The difference in charging potential between the first and second laps of the electrophotographic photosensitive member (charging potential difference) is measured by the electrophotographic apparatus at the developing means position after charging of the electrophotographic photosensitive member of the electrophotographic apparatus. The surface potential difference between the first and second laps of the photoreceptor was read as the charging potential difference.

Example 1 A solution prepared by dissolving 10 parts of a copolymerized nylon resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) in a mixed solution of 60 parts of methanol / 40 parts of butanol was immersed in an aluminum cylinder. Apply, 9
It was heated and dried at 0 ° C. for 10 minutes to form an intermediate layer having a film thickness of 0.5 μm.

Next, the Bragg angle (2θ ± 2) in the CuKα characteristic X-ray diffraction having the structure represented by the following formula (2) is obtained.
3 parts of hydroxygallium phthalocyanine pigment having strong peaks at 7.4 °, 16.6 °, 25.5 ° and 28.2 ° of 0.2 °),

[Outside 4]

A mixed solution containing 2 parts of polyvinyl butyral resin (trade name: S-REC BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 70 parts of cyclohexanone was used in a sand mill to prepare a mixed solution.
After time-dispersed, 100 parts of ethyl acetate was added to prepare a charge generation layer coating liquid. This coating solution is applied onto the intermediate layer prepared above by dip coating, and dried by heating at 90 ° C. for 10 minutes,
A charge generation layer having a thickness of 0.17 μm was formed.

Next, 7 parts of a triarylamine compound having a structure represented by the following formula (3):

[Outside 5]

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

For the charge injection layer, 50 parts of antimony-doped tin oxide ultrafine particles surface-treated with a compound having a structure represented by the following formula (4) (treatment amount: 7%):

[Outside 6]

150 parts of ethanol was placed in a sand mill.
Dispersion was performed for 66 hours (average particle size 0.03μ
m). After that, resol type phenol resin (trade name: P
L-4804: Amine compound catalyst used, Gunei Chemical Industry Co., Ltd.) was used as a resin component to dissolve 30 parts to prepare a preparation liquid, and a film was formed on the above charge transport layer by a dip coating method. Film thickness 4μm after drying with hot air at 145 ° C for 1 hour
An electrophotographic photoreceptor having the charge injection layer of was obtained. This time,
The dispersion state of the charge injection layer coating was good, and the produced charge injection layer was a uniform and uniform film.

The electrophotographic photosensitive member thus produced was mounted on the above-mentioned modified laser jet 4000 and the ΔVd was measured, and it was 40V.

A halftone image was output with the above-mentioned device configuration. If the injection charging on the image is not performed properly, black stripes may appear during reversal development, and the charge potential of the second rotation of the photoconductor may become lower due to the exposure history of the first rotation, resulting in a halftone image. Image defects such as increased density appear on one image. However, in the apparatus structure having the electrophotographic photosensitive member of the present invention, no increase in density was observed, and a high-quality image could be output even after continuous output of 1000 sheets. In addition, as a result of observing the surface of the photoconductor with a microscope after outputting the image, no scratch was found on the surface of the photoconductor.

Example 2 An electrophotographic photoreceptor was prepared in exactly the same manner except that a charge generation layer, a charge transport layer and a charge injection layer were provided on the intermediate layer prepared in Example 1 as follows. .

The structure represented by the following formula (5):
Bragg angle (2θ ± 0.2 in Kα characteristic X-ray diffraction
2 parts of an oxytitanium phthalocyanine pigment having strong peaks at 9.0 ° and 27.1 °.

[Outside 7]

A mixed solution containing 2 parts of polyvinyl butyral resin (trade name: S-REC BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 70 parts of cyclohexanone was used in a sand mill to prepare a mixed solution.
After time-dispersed, 100 parts of ethyl acetate was added to prepare a charge generation layer coating liquid. This coating solution is applied onto the intermediate layer prepared above by dip coating, and dried by heating at 90 ° C. for 10 minutes,
A charge generation layer having a thickness of 0.17 μm was formed.

Next, 7 parts of a triarylamine compound having a structure represented by the following formula (6):

[Outside 8]

Polycarbonate (trade name: Iupilon Z
A solution prepared by dissolving 10 parts of -200, manufactured by Mitsubishi Gas Chemical Co., Inc. in 70 parts of chlorobenzene is dip-coated on the charge generation layer, and dried by heating at 110 ° C. for 1 hour to give a film thickness of 15 μm. Was formed on the charge transport layer.

As the charge injection layer, 50 parts of antimony-doped tin oxide ultrafine particles surface-treated with a compound having the structure represented by the above formula (4) (treatment amount 7%), melamine resin (Cymel 701, Mitsui Cytec Co., Ltd.) Made) 30 parts,
And 150 parts of ethanol were dispersed in a sand mill for 66 hours to prepare a preparation liquid.

Further, using this coating composition, a surface film was formed on the charge transport layer of the electrophotographic photosensitive member 1 by a dip coating method on the charge transport layer, followed by hot air drying at 150 ° C. for 1 hour. A charge injection layer having a thickness of 3 μm was formed.

The produced electrophotographic photosensitive member was mounted on the modified laser jet 4000 used in Example 1 and ΔVd was measured. As a result, ΔVd was 69V.

As in Example 1, when a halftone image was output with this apparatus configuration, a slight ghost was seen, although at an acceptable level. Also, 10
As a result of observing the surface of the photoreceptor with a microscope after continuously outputting 00 sheets, no scratch was found on the surface of the photoreceptor.

Comparative Example 1 The charge transport layer of the electrophotographic photosensitive member prepared in Example 2 was 15 μm, the melamine resin used for the charge injection layer was 30 to 10 parts, and the film thickness was 1.5.
An electrophotographic photosensitive member was produced in exactly the same manner except that the thickness was changed to μm. When evaluated in the same manner as in Example 1, ΔVd
Was 75V. Further, when a futone image was output, an image defect in which the density was remarkably increased occurred. This is because at the portion where the photosensitive member was charged and exposed during the first rotation, a part of the charge generated during the exposure history stays in the photosensitive layer, and during the second charging, only that portion has a potential. It was thought that this was due to a decrease in image quality and an increase in image density. After continuously outputting 1,000 sheets, the surface of the photoconductor was observed with a microscope, and as a result, no scratch was found on the surface of the photoconductor.

Comparative Example 2 Similar to Example 1 except that the charge generating layer of the electrophotographic photosensitive member prepared in Example 2 was prepared as described below and the thickness of the charge transport layer was 10 μm. It was set up. Further, a charge injection layer was formed on the charge transport layer in the same manner as in Example 2 to obtain an electrophotographic photoreceptor.

1.125 parts of a trisazo pigment having a structure represented by the following formula (7):

[Outside 9]

2 parts of polyvinyl benzal having a structure represented by the following formula (8) (benzalization rate 80%, weight average molecular weight 12000)

[Outside 10]

After dispersing 30 parts of cyclohexanone and a sand mill, 60 parts of tetrahydrofuran was added to prepare a charge generation layer coating solution. This coating liquid was applied onto the intermediate layer by dip coating and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.4 μm.

When evaluated in the same manner as in Example 1, ΔVd was 70V. Further, when a futone image was output, the image defect of increased density observed in Comparative Example 1 was observed. In addition, after continuously printing 1000 sheets, the surface of the photoconductor was observed with a microscope, and as a result, no scratch was found on the surface of the photoconductor.

Example 3 An electrophotographic photosensitive member was produced in exactly the same manner except that the charge injection layer produced in Example 1 was formed as described below.

The coating material for the charge injection layer was surface-treated with a compound having the structure represented by the above formula (4) (treatment amount 7
%) 50 parts of antimony-doped tin oxide ultrafine particles were dispersed together with 150 parts of ethanol in a sand mill for 66 hours. Furthermore, 20 parts of a charge transport material having a structure represented by the following formula (9), and a resin component of a resole type curable phenol resin manufactured by Sumitomo Dures Co., Ltd. (trade name: P
R-53123, nonvolatile content: 45%) was used as a nonvolatile content, and 30 parts was dissolved in the above dispersion liquid to obtain a charge injection layer coating material. This was dried on the charge transport layer with hot air at a temperature of 145 ° C. for 1 hour to obtain an electrophotographic photosensitive member having a charge injection layer of 2 μm.

[0191]

[Outside 11]

When the manufactured electrophotographic photosensitive member was measured for ΔVd with a modified laser jet 4000 in the same manner as in Example 1, ΔVd was 34V. Alternatively, when a futone image was output, a high-quality image with no density increase could be output. After continuously outputting 1000 sheets of images, the surface of the photoconductor was observed with a microscope. As a result, no scratch was found on the surface of the photoconductor.

Example 4 By the method described in Example 1,
On the aluminum cylinder, the intermediate layer and the charge generation layer were formed by changing the film thickness to 0.2 μm, and the charge transport layer having a thickness of 25 μm was provided by the method described in Example 2. A charge injection layer having a thickness of 2 μm was formed on the charge transport layer by the method described in Example 1 to prepare an electrophotographic photosensitive member.

When the manufactured electrophotographic photosensitive member was measured for ΔVd with a modified laser jet 4000 in the same manner as in Example 1, ΔVd was 22V. Also, when a futone image was output, a high-quality image with no density increase could be output. After continuously outputting 1000 sheets of images, the surface of the photoconductor was observed with a microscope. As a result, no scratch was found on the surface of the photoconductor.

Example 5 By the method described in Example 1,
An intermediate layer and a charge generation layer were sequentially formed on an aluminum cylinder, and only the charge transport layer was changed to 10 μm, and the charge transport layer was also prepared. Further, the phenol resin used in the charge injection layer of Example 1 was replaced with Japan Epoxy Resin Co., Ltd.
Made Epicoat # 815 and Epomate B002 2: 1
A 1 μm charge injection layer was provided in place of the epoxy resin blended (mass ratio) to prepare an electrophotographic photoreceptor.

When the electrophotographic photosensitive member thus produced was measured for ΔVd with a modified laser jet 4000 in the same manner as in Example 1, ΔVd was 21V. Also, when a halftone image was output, a high-quality image with no density increase could be output. Furthermore, after the continuous image output of 1000 sheets, the surface was observed with a microscope, but no scratches were found.

Example 6 An intermediate layer and a charge generation layer were provided on an aluminum cylinder by the method described in Example 2, and then a charge transport layer was provided by 25 μm by the method described in Example 1. Further, the phenol resin used in the charge injection layer of Example 1 was replaced with methylphenylpolysiloxane (K
F-50500CS: manufactured by Shin-Etsu Silicone Co., Ltd., a surface film was formed by a dip coating method, followed by heat drying at 160 ° C. for 1 hour to provide a 2 μm charge injection layer.

Using this electrophotographic photosensitive member, ΔVd was measured in the same manner as in Example 1. As a result, ΔVd was 18V. Alternatively, when a futone image was output, a high-quality image with no density increase was output. Furthermore, consecutive 1
When 000 sheets were output, a high-quality image could be output, but when the photoreceptor after output was observed with a microscope, slight scratches that did not appear on the image were observed.

Example 7 An intermediate layer was prepared on an aluminum cylinder by the method described in Example 2, and the oxytitanium phthalocyanine used in the charge generation layer described in Example 2 was replaced with 2 parts to 5 parts. A charge generation layer was prepared.
Further, the charge transport layer described in Example 2 is provided in a thickness of 30 μm,
The charge injection layer described in Example 5 was provided thereon with a thickness of 0.5 μm.

Using this electrophotographic photosensitive member, ΔVd was measured in the same manner as in Example 1. As a result, ΔVd was 6V. Also, when a halftone image was output, a high-quality image with no density increase was output. Furthermore, when 1000 sheets were continuously output, a high-quality image could be output, but when the photoconductor after the output was observed with a microscope, slight scratches that did not appear on the image were observed.

Comparative Example 3 By the method described in Comparative Example 2, an intermediate layer was provided on an aluminum cylinder and the charge generation layer was 0.1 μm. A charge transport layer was applied by the method described in Example 7, and a charge injection layer was provided as described below.

As the charge injecting layer, 50 parts of antimony-doped tin oxide ultrafine particles described in Example 1, the following formula (10) was used.
UV curable acrylic resin having a structure shown by
0 parts, 3 parts of 2-methylthioxanthone and 150 parts of ethanol were dispersed in a sand mill for 66 hours to prepare a preparation liquid.

[0203]

[Outside 12]

Further, using this coating composition, after forming a surface layer on the charge transport layer by the dip coating method, it was cured by a high pressure mercury lamp at a light intensity of 800 mW / cm ² for 30 seconds,
Then, it was dried with hot air at 120 ° C. for 2 hours to form a charge injection layer having a film thickness of 3 μm.

When this electrophotographic photosensitive member was mounted on the apparatus used for evaluation in Example 1 and ΔVd was measured, ΔVd was 4V.

As in Example 1, when a halftone image was output in this apparatus configuration, it was possible to output an image with no increase in density. But,
When 1000 sheets were continuously output, the toner recycling system in this apparatus caused ejection failure in which the toner collected by the charger could not be properly ejected onto the drum, resulting in an image defect. It is considered that this is because the toner was excessively accumulated in the charger due to the defective discharge of the toner in the charger, and the toner was contaminated by the toner, resulting in a defective image. When the surface of the photoconductor was observed with a microscope after the image was output, many scratches were found in the driving direction. It is considered that this is because the toner is defectively ejected in the developing device, and the toner enters between the developing device and the photoconductor, and is rotated, and is rotated to cause a scratch.

Example 8 Except that the charge injection layer of the electrophotographic photosensitive member used in Example 1 was prepared as follows,
A charge injection layer was formed on the charge transport layer and evaluated in exactly the same manner as in Example 1.

30 parts of antimony-doped tin oxide ultrafine particles surface-treated with a compound having the structure represented by the above formula (4) (treatment amount: 7%) for the charge injection layer, having the structure represented by the above formula (1) 30 parts of antimony-doped tin oxide fine particles (20%) surface-treated with methyl hydrogen silicone oil (trade name: KF99, manufactured by Shin-Etsu Silicone Co., Ltd.) were added, and 150 parts of ethanol were added in a sand mill for 66 hours. Dispersed (average particle size 0.03
μm). Furthermore, 20 parts of polytetrafluoroethylene fine particles (average particle size 0.18 μm) were added, and further 2
Time dispersion was performed.

After that, 30 parts of a resol type phenol resin (trade name: PL-4852; using an amine compound catalyst, manufactured by Gunei Chemical Industry Co., Ltd.) as a resin component was dissolved to prepare a preparation liquid, which was then subjected to a dip coating method. A film is formed on the charge transport layer and dried by hot air at a temperature of 145 ° C. for 1 hour to give a film thickness of 4
An electrophotographic photoreceptor having a charge injection layer of μm was obtained. At this time, the dispersion state of the charge injection layer coating material was good, and the produced charge injection layer was a uniform and uniform film.

The electrophotographic photosensitive member thus prepared was mounted on the modified laser jet 4000 used in Example 1 and ΔVd was measured. As a result, ΔVd was 33V.

As in Example 1, when a halftone image was output in this apparatus configuration, a high-quality image without image defects was obtained. Furthermore, after the continuous image output of 1000 sheets, the surface was observed with a microscope, but no scratches were found.

[0212]

As described above, according to the present invention,
It is possible to always provide stable toner recycling, provide high-quality images with little ghost, and provide an electrophotographic apparatus that does not cause scratches on the electrophotographic photosensitive member even after repeated output. became.

It is also possible to provide a process cartridge and an electrophotographic photosensitive member for the electrophotographic apparatus.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a resistance measuring method of an elastic charging member.
(A) Volume resistance measurement, (b) Surface resistance measurement

FIG. 3 is a diagram showing a schematic configuration of an apparatus for measuring a triboelectric charge amount of toner particles.

FIG. 4 is a diagram showing an example of a layer structure of an electrophotographic photosensitive member of the present invention.

FIG. 5 is a diagram showing a schematic configuration of a charged particle supply member of the electrophotographic apparatus of the present invention.

FIG. 6 is a diagram showing a schematic configuration of a process cartridge having the electrophotographic photosensitive member of the present invention.

[Explanation of symbols]

1 Electrophotographic photoreceptor 2 charging means 2a core metal 2b Medium resistance layer (elastic layer) M charged particles 3A charged particle supply member 37A stirring blade 38A housing container 39a fur brush 4 Exposure means L exposure light 6 Transfer means 60 1-component magnetic developing device 60a rotating developing sleeve 60b magnet roll 60c regulation blade 60d stirring member 60e developing container 7 fixing means 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 91 suction machine 92 Measuring container 93 screen 94 lid 95 vacuum gauge 96 Air flow control valve 97 Suction port 98 condenser 99 electrometer 61 charge injection layer 62 charge transport layer 63 Charge generation layer 64 support 65 Conductive layer 66 Middle class S1, S2, S3, S4, S5 Applied power supply

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/00 G03G 15/00 15/08 507 15/08 507B (72) Inventor Kimihiro Yoshimura Ota-ku, Tokyo 3-30-2 Shimomaruko Canon Inc. (72) Inventor Koichi Nakata 3-30-2 Shimomaruko Ota-ku, Tokyo Canon Inc. F-term (reference) 2H068 AA03 AA04 AA05 AA06 BA05 BA13 BA53 BA58 BA61 BB30 BB31 BB33 BB34 BB35 BB58 CA05 CA32. QB54 QC03 TB02 TB06 TB13 UA03 2H200 FA09 FA14 FA18 GA16 GA23 GA46 GA49 GB35 GB37 HA03 HA21 HA28 HA29 HB12 HB17 HB22 HB43 HB45 HB46 HB47 HB4 8 LA38 LC02 MA03 MA08 MA13 MA14 MB01 MB04 MC01 MC06 MC11 MC15 NA02 PA05 PA10 PA20 PA22

Claims (43)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a support, a charging means for charging the surface of the electrophotographic photoreceptor, and an electrostatic latent image on the surface of the electrophotographic photoreceptor charged by the charging means by exposure. An exposing unit that forms an image, a developing unit that develops the electrostatic latent image formed by the exposing unit with toner to form a toner image, and a toner image formed by the developing unit is transferred to a recording medium. What is claimed is: 1. An electrophotographic apparatus comprising: a transfer unit; and a fixing unit that fixes the toner image transferred onto the recording medium by the transfer unit onto the recording medium, wherein the charging unit is provided on the surface of the electrophotographic photosensitive member. A means for charging the surface of the electrophotographic photosensitive member by directly injecting an electric charge from the contact charging member to the electrophotographic photosensitive member, the contact charging member being provided with the contact charging member. Charge that comes into contact with the body An electrophotographic apparatus, which is a member having a child and a charged particle carrier that carries the charged particles and has conductivity and elasticity on the surface, wherein the charging unit is the electrophotographic photosensitive member after transfer by the transfer unit. The developing means functions as a means for carrying the residual toner remaining on the body surface to normalize the electric charge of the residual toner and returning the electric charge-normalized residual toner to the surface of the electrophotographic photosensitive member. In an electrophotographic apparatus having a toner recycling structure that also serves as means for recovering residual toner whose electric charge is normalized and returned to the surface of the electrophotographic photosensitive member, a charging potential of the first and second laps of the electrophotographic photosensitive member An electrophotographic apparatus, wherein the absolute value of the difference (charge potential difference) is larger than 5V and smaller than 70V. 2. The electrophotographic apparatus according to claim 1, wherein an absolute value of a difference in charging potential (charging potential difference) between the first and second rounds of the electrophotographic photosensitive member is larger than 20V and smaller than 70V. 3. The electrophotographic photosensitive member has a charge injection layer as a surface layer, and the charging unit directly injects charges from the contact charging member to the charge injection layer, thereby exposing the surface of the electrophotographic photosensitive member. The electrophotographic apparatus according to claim 1, which is a means for charging. 4. The electrophotographic apparatus according to claim 3, wherein the charge injection layer of the electrophotographic photosensitive member contains a binder resin and further contains at least one of conductive particles and a charge transport substance. 5. The electrophotographic apparatus according to claim 4, wherein the binder resin contained in the charge injection layer of the electrophotographic photosensitive member is a curable resin. 6. The electrophotographic apparatus according to claim 5, wherein the curable resin is at least one resin selected from the group consisting of a phenol resin, an epoxy resin and a siloxane resin. 7. The electrophotographic apparatus according to claim 6, wherein the charge injection layer of the electrophotographic photosensitive member contains a phenol resin, and the phenol resin is a resol type phenol resin. 8. The electrophotographic apparatus according to claim 7, wherein the resol-type phenol resin is a resin synthesized using ammonia or an amine compound. 9. The electrophotographic apparatus according to claim 8, wherein the resol-type phenol resin is a resin synthesized by using an amine compound. 10. The electrophotographic apparatus according to claim 9, wherein the charge injection layer of the electrophotographic photosensitive member contains a phenol resin, and the phenol resin is a thermosetting phenol resin which is cured by heat. 11. The electrophotographic apparatus according to claim 4, wherein the charge injection layer of the electrophotographic photosensitive member contains conductive particles, and the conductive particles are metal particles or metal oxide particles. . 12. The charge injection layer of the electrophotographic photosensitive member,
The electrophotographic apparatus according to any one of claims 3 to 11, which contains at least one of a fluorine atom-containing compound and a siloxane compound. 13. The charge injection layer contains a fluorine atom-containing compound, and the fluorine atom-containing compound is selected from the group consisting of a fluorine-containing silane coupling agent, a fluorine-modified silicone oil and a fluorine-based surfactant. Item 1
The electrophotographic apparatus according to 2. 14. The electrophotographic apparatus according to claim 12, wherein the charge injection layer contains a siloxane compound, and the siloxane compound is a siloxane compound having a structure represented by the following formula (1). [Outer 1] (In the formula, A is a hydrogen atom or a methyl group, and A
The ratio of hydrogen atoms to the total is in the range of 0.1 to 50%. n is a positive integer of 0 or more. ) 15. The charge injection layer of the electrophotographic photosensitive member,
The electrophotographic apparatus according to any one of claims 3 to 14, which contains lubricating particles. 16. The lubricating particles contained in the charge injection layer of the electrophotographic photosensitive member are at least one particle selected from the group consisting of fluorine atom-containing resin particles, silicone particles, silicon particles and alumina particles. Item 15
The electrophotographic apparatus according to 1. 17. The charged particles carried by the charged particle carrier are mainly composed of conductive particles having a particle size of 10 nm or more and 10 μm or less, and the resistance of the charged particles is 10 ⁻¹ Ω · cm or more 1.
0 ¹² Ω · cm or less, and the carried amount of the charged particles of the charged particle carrier is 0.1 mg / cm ² or more and 50 mg / cm ²
The electrophotographic apparatus according to claim 1, which is as follows. 18. A rate (coverage rate) with which the charged particles carried by the charged particle carrier cover the surface of the charged particle carrier.
Is 0.2 or more and 1 or less, The electrophotographic apparatus according to claim 1. 19. The surface roughness Ra of the charged particle carrier is 1 μm or more and 500 μm or less, and the surface resistance of the charged particle carrier is 10 ⁴ Ω □ or more and 10 ¹⁰ Ω □ or less. The electrophotographic apparatus according to any one. 20. The electrophotographic apparatus according to claim 1, wherein the charged particle carrier is an elastic body having a porous body surface. 21. The electrophotographic apparatus according to claim 1, wherein the charging unit has a charged particle supply member that supplies charged particles to the charged particle carrier. 22. An electrophotographic photosensitive member having a photosensitive layer on a support, a charging unit for charging the surface of the electrophotographic photosensitive member, and an exposing unit after charging the surface of the electrophotographic photosensitive member by the charging unit. Developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with toner to form a toner image, and transfer means for transferring the toner image formed by the developing means onto a recording medium. A process cartridge that integrally supports a fixing unit that fixes the toner image transferred onto the recording medium by the transfer unit onto the recording medium, and is detachable from the main body of the electrophotographic apparatus. A means for charging the surface of the electrophotographic photosensitive member by directly injecting an electric charge from the contact charging member to the electrophotographic photosensitive member, the contact charging member being in contact with the surface of the electrophotographic photosensitive member. Charging member Is a process cartridge that is a member having charged particles that come into contact with the electrophotographic photosensitive member and a charged particle carrier that carries the charged particles and that has conductivity and elasticity on the surface, After the toner image formed on the surface of the electrophotographic photosensitive member by the developing unit is transferred to the recording medium by the transfer unit, the residual toner remaining on the surface of the electrophotographic photosensitive member is carried, and the charge of the residual toner is charged. Normalize
The developing unit also serves as a unit for returning the residual toner whose electric charge is normalized to the surface of the electrophotographic photosensitive member, and the developing unit collects the residual toner whose electric charge is normalized by the charging unit and returned to the surface of the electrophotographic photosensitive member. In a process cartridge having a toner recycling structure that also serves as a means,
A process cartridge characterized in that the absolute value of the difference in charging potential between the second and second cycles (charging potential difference) is larger than 5V and smaller than 70V. 23. The process cartridge according to claim 22, wherein the absolute value of the difference in charging potential (charging potential difference) between the first and second rounds of the electrophotographic photosensitive member is larger than 20V and smaller than 70V. 24. The electrophotographic photosensitive member has a charge injection layer as a surface layer, and the charging unit directly injects charges from the contact charging member to the charge injection layer, thereby exposing the surface of the electrophotographic photosensitive member. 24. A means for charging, 22 or 23
The process cartridge described in 1. 25. The charge injection layer of the electrophotographic photosensitive member,
25. The process cartridge according to claim 24, which contains a binder resin and further contains at least one of conductive particles and a charge transport substance. 26. The process cartridge according to claim 25, wherein the binder resin contained in the charge injection layer of the electrophotographic photosensitive member is a curable resin. 27. The process cartridge according to claim 26, wherein the curable resin is at least one resin selected from the group consisting of a phenol resin, an epoxy resin and a siloxane resin. 28. The process cartridge according to claim 27, wherein the charge injection layer of the electrophotographic photosensitive member contains a phenol resin, and the phenol resin is a resol type phenol resin. 29. The process cartridge according to claim 28, wherein the resol-type phenol resin is a resin synthesized using ammonia or an amine compound. 30. The process cartridge according to claim 29, wherein the resol-type phenol resin is a resin synthesized by using an amine compound. 31. The process cartridge according to claim 30, wherein the charge injection layer of the electrophotographic photosensitive member contains a phenol resin, and the phenol resin is a thermosetting phenol resin which is cured by heat. 32. The process cartridge according to claim 25, wherein the charge injection layer of the electrophotographic photosensitive member contains conductive particles, and the conductive particles are metal particles or metal oxide particles. 33. The charge injection layer of the electrophotographic photosensitive member,
33. The process cartridge according to claim 24, containing at least one of a fluorine atom-containing compound and a siloxane compound. 34. The charge injection layer contains a fluorine atom-containing compound, and the fluorine atom-containing compound is selected from the group consisting of a fluorine-containing silane coupling agent, a fluorine-modified silicone oil and a fluorine-based surfactant. Item 3
3. The process cartridge according to item 3. 35. The process cartridge according to claim 33, wherein the charge injection layer contains a siloxane compound, and the siloxane compound is a siloxane compound having a structure represented by the following formula (1). [Outside 2] (In the formula, A is a hydrogen atom or a methyl group, and A
The ratio of hydrogen atoms to the total is in the range of 0.1 to 50%. n is a positive integer of 0 or more. ) 36. The charge injection layer of the electrophotographic photosensitive member,
The process cartridge according to any one of claims 24 to 35, which contains lubricious particles. 37. The lubricating particles contained in the charge injection layer of the electrophotographic photosensitive member are at least one particle selected from the group consisting of fluorine atom-containing resin particles, silicone particles, silicon particles and alumina particles. Item 36
The process cartridge described in 1. 38. The charged particles carried by the charged particle carrier are mainly composed of conductive particles having a particle size of 10 nm or more and 10 μm or less, and the resistance of the charged particles is 10 ⁻¹ Ω · cm or more 1.
0 ¹² Ω · cm or less, and the carried amount of the charged particles of the charged particle carrier is 0.1 mg / cm ² or more and 50 mg / cm ²
38. The process cartridge according to claim 22, which is as follows. 39. A ratio (coverage ratio) of the charged particles carried by the charged particle carrier to cover the surface of the charged particle carrier.
39. The process cartridge according to claim 22, wherein the value is 0.2 or more and 1 or less. 40. The surface roughness Ra of the charged particle carrier is 1 μm or more and 500 μm or less, and the surface resistance of the charged particle carrier is 10 ⁴ Ω □ or more and 10 ¹⁰ Ω □ or less. The process cartridge according to any one. 41. The process cartridge according to claim 22, wherein the charged particle carrier is an elastic body having a porous body surface. 42. The process cartridge according to claim 22, wherein the charging unit has a charged particle supply member that supplies charged particles to the charged particle carrier. 43. An electrophotographic photosensitive member, which is used in the electrophotographic apparatus according to claim 1.