JP2003043817A - Electrophotographic device and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaner-less system electrophotographic device capable of realizing the compatibility of trouble on toner welding and fogging, and a process cartridge. SOLUTION: This electrophotographic device is provided with an electrophotographic photoreceptor, an electrifying means for electrifying the photoreceptor, an information writing means for forming an electrostatic latent image on the photoreceptor processed to be electrified, a developing means for supplying developer to the electrostatic latent image and making the electrostatic latent image visualizable, a transfer means for transferring a developer image made visualizable to transfer material, and a developer electrified amount control means for electrifying the developer on the surface of the photoreceptor and positioned on a more upstream side than the electrifying means. In the device, the developer electrified amount control means processes to electrify the developer remaining on the photoreceptor after a transfer stage to have a normal polarity, and the electrifying means electrifies the surface of the photoreceptor and simultaneously makes electrified amount appropriate. Then, the photoreceptor incorporates polyallylate resin in its surface layer. Thus, the electrophotographic device and the process cartridge are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus and a process cartridge, and more particularly to an electrophotographic apparatus and a process cartridge that do not require a cleaner.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic apparatus using an electrophotographic system such as a copying machine, a printer or a facsimile is an electrophotographic photosensitive member which is a latent image carrier, a charging device for charging the electrophotographic photosensitive member, and an electronic device. A developing device that visualizes the electrostatic latent image formed on the photographic photoconductor with toner that is a developer, a transfer device that transfers the toner to a transfer material such as paper, and then remains on the electrophotographic photoconductor. It comprises a cleaning device for cleaning the residual toner, a fixing device for fixing the toner on the transfer material, and the like.

In recent years, from the viewpoint of environmental protection and effective use of resources, an electrophotographic apparatus has been developed in which transfer residual toner, so-called waste toner, collected by a cleaning device is returned to a developing device for reuse. As one of the methods, there is a cleanerless method in which the cleaning device is eliminated and the transfer residual toner is cleaned in the developing device at the same time as the developing process.

The transfer residual toner remaining on the electrophotographic photosensitive member after the transfer is removed from the surface of the electrophotographic photosensitive member by a cleaning device to become waste toner, but the cleaner is eliminated and the transfer residual toner on the electrophotographic photosensitive member after the transfer is removed. There is proposed a cleanerless process electrophotographic apparatus in which toner is removed from the electrophotographic photosensitive member by a developing apparatus and is collected and reused in the developing apparatus. For example, JP-A-8
Japanese Patent Laid-Open No. 137368 discloses that an auxiliary charging unit for charging transfer residual toner to the charging roller, which has the same polarity as the charging unit and has a higher potential, is provided on the upstream side of the charging roller which is the charging unit. While preventing the stain due to the adhesion of the residual toner, the AC voltage is superposed on the charging roller to perform uniform charging, and at the same time, the residual transfer toner is discharged to be collected by the developing device.

[0005]

However, in this process, when the AC voltage superimposed on the charging roller is high, the surface of the electrophotographic photosensitive member is roughened by the oscillating electric field, and the nip portion between the charging roller and the electrophotographic photosensitive member is transferred. When the residual toner passes through, a phenomenon of adhesion, that is, toner fusion, occurs on the surface of the electrophotographic photosensitive member, causing an image defect. On the other hand, when the AC voltage is low, the charge of the transfer residual toner is not properly removed, so that it is difficult to collect in the developing device and a fog image is generated. That is, the superposed AC
Unless the voltage is accurately controlled, it is difficult to make these two problems compatible.

An object of the present invention is to provide an electrophotographic apparatus and a process cartridge of a cleanerless system which can solve the problems of toner fusion and fogging.

[0007]

According to the present invention, an electrophotographic photosensitive member, a charging means for charging the electrophotographic photosensitive member, and an information writing means for forming an electrostatic latent image on the charged electrophotographic photosensitive member. A developing unit for supplying a developer to the electrostatic latent image to visualize the electrostatic latent image; a transferring unit for transferring the visualized developer image to a transfer material; and an electrophotographic apparatus located upstream of the charging unit. A developer charge amount control means for charging the developer on the surface of the photoconductor is provided, and the developer remaining on the electrophotographic photoconductor after the transfer step is charged to a normal polarity by the developer charge amount control means. An electrophotographic apparatus for charging the surface of the electrophotographic photosensitive member by the charging unit and at the same time providing an appropriate amount of charge, wherein the electrophotographic photosensitive member contains a polyarylate resin in a surface layer Cartridge provided That.

[0008]

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

The above problem can be solved by allowing the electrophotographic photosensitive member according to the present invention to simultaneously contain a polyarylate resin and a silicone-modified polycarbonate resin in the surface layer.

The polyarylate resin is disclosed in JP-A-10-20.
As described in JP-A No. 519 and JP-A No. 10-20523, and as described in these publications, it is a thermoplastic resin having excellent mechanical abrasion resistance. That is,
Even if an oscillating electric field for charging is applied, the occurrence of surface roughness is small, and it is considered that toner adhesion is suppressed. On the other hand, since the silicone-modified polycarbonate of the present invention has excellent lubricity as described in JP-A-6-295075, etc., it has an excellent effect of preventing toner adhesion. Conceivable.

Next, the cleanerless type electrophotographic apparatus will be described with reference to FIG. In FIG. 1, negative DC voltage and AC voltage are simultaneously applied to the charging roller to negatively charge the photosensitive drum, an electrostatic latent image is written by laser light, and the negatively charged developer is applied to the photosensitive drum by the developing device. An example of the reversal development method in which development is performed on the exposed portion of

In FIG. 1, the photosensitive drum 1 first rotates in the direction of the arrow and is charged by a charging device (charging roller) 2. After that, the image information is written as an electrostatic latent image by the exposure unit 3 and visualized as a toner image by the developing device 4. The visualized toner image on the photosensitive drum is transferred to a transfer material 6 by a transfer device (transfer roller) 5, and then the transfer material 6 is conveyed to a fixing device (not shown). After the transfer step, the residual toner remaining on the electrophotographic photosensitive member 1 is charged by the auxiliary charging device 7 to the same polarity as that of the charging and to a higher potential, and the charge is removed by alternating current in the charging step. After passing through the exposure process, it is collected in the developing container by the developing device and used again for the developing process. Thereafter, the above process is repeated. The auxiliary charging means shown in FIG. 1 uses a fixed brush-shaped member,
It may be a member of any form such as a brush rotating body, an elastic roller body or a sheet-like member. Further, this member can be made to thrust the electrophotographic photosensitive member in the longitudinal direction thereof to make the potential imparting property more uniform.

Further, the residual developer image is uniformed upstream of the developer charge amount control means (the above-mentioned auxiliary charging device 7) for charging the developer as the auxiliary charging means and downstream of the transfer means. It is also possible to add an auxiliary charging device 8 as a charging means. FIG. 2 shows an electrophotographic apparatus having two auxiliary charging devices.

Auxiliary charging means (means for uniforming residual developer image)
Although a fixed brush-like member is used for the member 8 in this figure, it may be any member such as a brush rotating body, an elastic roller body, or a sheet-like member. Further, this member can be thrust in the longitudinal direction of the electrophotographic photosensitive member to make the potential imparting property more uniform. Furthermore, the auxiliary charging device 7 can be grounded or a bias can be applied as necessary.

Next, the electrophotographic photosensitive member according to the present invention will be described in detail.

As the electrophotographic photosensitive member according to the present invention, a laminated type in which a charge transport layer and a charge generation layer are separated and the surface layer is a charge transport layer will be described with reference to FIG. In this electrophotographic photosensitive member, an undercoat layer 13, a charge generation layer 14, and a charge transport layer 15 for the purpose of preventing interference fringes and the like are sequentially provided on a conductive support 11. Further, the conductive layer 12 may be provided between the conductive support 11 and the undercoat layer 13.

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

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

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

A charge generation layer is formed on the undercoat layer. The charge generation layer used in the present invention is formed by applying and drying a coating material in which a charge generation material and a binder resin are dispersed in a solvent. In the case of the function separation type, the charge generation layer includes a charge generation material together with a binder resin and a solvent, a homogenizer, ultrasonic dispersion, a ball mill, a vibrating ball mill, a sand mill,
Disperse evenly by a method such as an attritor, a roll mill or a liquid collision type high speed disperser. Examples of the charge generating material used here include pyrylium, thiapyrylium dye, phthalocyanine, anthanthrone, dibenzpyrenequinone, trisazo, cyanine, disazo, monoazo, indigo, quinacridone and asymmetric quinocyanine pigments.

Examples of the binder resin include polyester resin, polyacrylic resin, polyvinylcarbazole resin, phenoxy resin, polycarbonate resin, polystyrene resin, polyvinyl acetate resin, polysulfone resin, polyarylate resin, vinyldene chloride, polyvinylbenzal resin, and the like. Examples thereof include polybutyral resin. The ratio of the pigment to the binder resin is preferably 1 / 0.1 to 1/10, more preferably 1/1 to 3/1. The thickness of the charge generation layer formed by coating and drying the dispersion is 5μ.
m or less is preferable, and 0.1 to 2 μm is particularly preferable.

The charge transport layer is mainly coated with a coating material prepared by dissolving the charge transport material and the polyarylate resin of the present invention as a binder resin, and further, dissolving the polyarylate resin and the silicone-modified polycarbonate in a suitable solvent that dissolves them. Work / dry to form.

Examples of the constitution of the polyarylate of the present invention include JP-A-10-20519 and JP-A-10-20.
Examples of these are described below, but the present invention is not limited to these, and those having the structure represented by Structural Unit Example 6 are preferable in the present invention.

[0024]

[Chemical 3]

In the silicone-modified polycarbonate used in the present invention, the proportion of the polymer having the constitutional unit represented by the formula (2) and the copolymer having the constitutional units represented by the formulas (2), (3) and (4). Must be controlled in consideration of solvent crack resistance, environmental stability with respect to durability and electrical characteristics, and manufacturing stability depending on solution stability. However, in equations (2), (3) and (4), The copolymer having the structural unit shown is preferably in the range of 0.1 to 95% by mass with respect to the polymer having the structural unit represented by the formula (2), and 0.5 to 80% by mass. The range of% is particularly preferable.

In particular, let α be the mass of the constitutional units represented by the formulas (2) and (3), and β be the constitutional unit represented by the formula (4).
When the value of β / (α + β) is in the range of 0.01 to 0.1, the proportion of the polymer is preferably in the range of 1 to 15% by mass and 3 to 10% by mass. Ranges are particularly preferred.

The mass of the constitutional units represented by the formulas (2) and (4) is γ, and the constitutional unit represented by the formula (3) is δ.
The value of δ / (γ + δ) is preferably 0.3 to 0.8, particularly preferably 0.4 to 0.8.

[0028]

[Chemical 4]

When the polyarylate resin and the silicone-modified polycarbonate resin are mixed in the present invention, it is preferable that A / B ≧ 1 when the masses of A and B are A and B, respectively.

Since the silicone-modified polycarbonate has a foaming property, if the mixing amount is increased, the film formation cannot be successful, so that it is preferable to use within the above mixing ratio range.

As the charge transport material used in the present invention, triarylamine compounds, hydrazone compounds,
Examples thereof include low molecular weight compounds such as stilbene compounds, pyrazoline compounds, oxazole compounds, triarylmethane compounds and thiazole compounds. As the binding of the charge transport layer, in addition to the polyarylate resin of the present invention and the silicone-modified polycarbonate, a polycarbonate resin is blended, or other resins such as polyacrylate resin, polyester resin, polystyrene resin, styrene-acrylonitrile. You may further mix a copolymer resin, a polymethacrylic acid ester resin, a styrene-methacrylic acid ester copolymer resin, or the like.

The charge transport material is combined with 0.5 to 2 times the amount of the binder resin, coated and dried to form the charge transport layer.
The thickness of the charge transport layer is preferably 5 to 40 μm, and particularly 1
It is preferably 5 to 30 μm.

The silicone powder lubricant used in the surface layer of the electrophotographic photosensitive member of the present invention may be any one as long as it improves the slipperiness of the surface of the electrophotographic photosensitive member and does not deteriorate the electrophotographic characteristics. The product may be used, but "Product Name: Aron GS-101CP" manufactured by Toagosei Kagaku Kogyo Co., Ltd. is particularly preferable.

Further, additives such as an antioxidant, an ultraviolet absorber and a plasticizer may be added to the charge transport layer if necessary.

[0035]

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

(Embodiment 1) FIG. 1 is a sectional view of an electrophotographic apparatus according to the present invention. In the electrophotographic apparatus in this embodiment, a voltage obtained by superimposing an AC voltage on a negative DC voltage is applied to the charging roller to negatively charge the photosensitive drum A.
In the reversal development type electrophotographic apparatus in which an electrostatic latent image is written by a laser beam using a C charging device, and negatively charged toner is developed on an exposed portion on a photosensitive drum by a developing device, the developer charging control means 7 is used. It uses a conductive brush. However, as the function, it is sufficient that the charge of the toner can be controlled to the normal side, so that the surface property and the resistance uniformity are not required, and the structure may be simple. In this example, conductive rayon was used. A negative DC voltage Vtc is applied to the conductive brush by a power source so that the conductive brush is discharged toward the surface of the photosensitive drum. After the transfer process, the transfer residual toner remaining on the electrophotographic photosensitive member 1 is
The discharge from the conductive brush or the rubbing / contact with the conductive brush charges the developer to a negative charge, which is a regular charge polarity, and passes through the developer charge control process. Although positive toner adheres to the conductive brush, it does not affect the function of controlling the charging polarity of the toner to the regular side. The range of the voltage Vtc applied to the conductive brush is that Vtc is on the negative side of Vdb when the surface potential before entering the developer charge control step is Vdb. Vdb> Vtc In the developer charge control step The surface potential after being discharged is V
In the case of da, it is determined by two conditions that Vda is in a range where it can converge to the potential Vd desired to be obtained in the charging process downstream thereof. The latter condition is as follows depending on the type of charging device. When the charging device is an AC charging device that applies a voltage obtained by superimposing an AC voltage on a DC voltage to the charging roller as in this embodiment, the surface potential Vda of the photosensitive drum after the developer charging control process is the desired potential Vd. Regardless of the positive side or the negative side, the potential Vd can be converged in the charging process, and therefore the applied voltage Vtc is not particularly limited except Vdb> Vtc.

In this example, an experiment was conducted under the following voltage settings.

Voltage applied to the charging device: DC-600V + A
C1000 to 2500Vpp Surface potential Vd after charging process; -600V Surface potential after exposure Vl; -600V Applied voltage to developing sleeve Vdev; DC-400V Applied voltage to transfer roller Vt; DC + 1000V Surface potential Vdb before developer charging control process + 100 ~-
Applied voltage Vt of 500V conductive brush (developer charge amount control means)
c; DC-1200V Charge start voltage Vth of conductive brush (developer charge amount control means); 600V Surface potential Vda after developer charge control process; -800V

The electrophotographic photosensitive member of the present invention uses an aluminum cylinder as a support, and a coating material composed of the following materials is applied to the support by a dipping method, and the temperature is 140 ° C.
And heat-cured for 30 minutes to form a conductive layer having a thickness of 15 μm.

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

Next, a solution prepared by dissolving 4.5 parts of N-methoxymethylated nylon and 1.5 parts of copolymerized nylon in a mixed solvent of 65 parts of methanol / 30 parts of n-butanol was applied onto this by a dipping method. An intermediate layer having a film thickness of 0.6 μm was formed.

Next, 3.5 parts of hydroxygallium phthalocyanine crystal having strong peaks at Bragg angles (2θ ± 0.2 °) of 7.4 ° and 28.2 ° in CuKα characteristic X-ray diffraction and polyvinyl butyral resin ( (Product name: S-REC BH-S, manufactured by Sekisui Chemical Co., Ltd.) 1 part was added to 120 parts of cyclohexanone and dispersed for 3 hours in a sand mill using 1 mmφ glass beads, and 120 parts of methyl ethyl ketone was added to dilute it to generate a charge A layer coating was prepared. This charge generation layer coating material was applied onto the undercoat layer by dip coating and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.15 μm.

Next, 8 parts of the charge transport material represented by the following formula (5)

[0044]

[Chemical 5] And 10 parts of the polyarylate resin represented by the above formula (1) (weight average molecular weight Mw = 110,000) with dimethoxymethane 3
It was dissolved in a mixed solvent of 3 parts / 60 parts of monochlorobenzene to obtain a charge transport layer coating liquid.

Coating with this coating by dipping method (constant coating speed)
Then, it was dried at 120 ° C. for 1 hour to form a charge transport layer having a film thickness of 20 μm (near the center).

The electrophotographic photosensitive member thus produced was mounted on the above-mentioned electrophotographic apparatus, and the AC voltage applied to the charging device was set to 1000 or 12 in an environment of 30 ° C./80%.
It was changed to five levels of 50, 1500, 2000 and 2500 Vp-p, and 5000 sheets were passed under each condition, and fogging due to toner fusion on the drum and toner recoverability was evaluated. The results are shown in Table 1. In the evaluation, in toner fusion, ◯: no problem, Δ: toner fusion occurred during durability, ×: toner fusion occurred in the initial several sheets,
Regarding fogging, ◯: no problem, Δ: fogging occurred during durability, ×: fogging occurred from the initial several sheets.

Example 2 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the charge transporting material in Example 1 was replaced by the compound of the following formula (6). The setting was evaluated. The results are shown in Table 1.

[0048]

[Chemical 6]

(Example 3) 9.5 parts of polyarylate resin in Example 1 and the silicone-modified polycarbonate represented by the above formulas (2), (3) and (4) (viscosity average molecular weight Mv = 40,000) 0 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the amount was set to 0.5 part, and the same settings as in Example 1 were evaluated. The results are shown in Table 1.

(Example 4) The same as Example 1 except that 0.1 part of the silicone powder lubricant (trade name: Aron GS-101CP, manufactured by Toagosei Chemical Industry Co., Ltd.) was added in Example 3. To prepare an electrophotographic photosensitive member, and
Evaluation was performed with the same setting as. The results are shown in Table 1.

Example 5 Example 5 is the same as Example 4, except that the charge transport material represented by the formula (5) was changed to 7.2 parts and the charge transport material represented by the formula (6) was changed to 0.8 part. An electrophotographic photosensitive member was produced in the same manner as in Example 1 and evaluated in the same setting as in Example 1. The results are shown in Table 1.

Example 6 An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that 8 parts of polyarylate resin and 2 parts of silicone-modified polycarbonate were used in Example 5. Evaluation was performed with the same setting as. The results are shown in Table 1.

Example 7 An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that 5 parts of polyarylate resin and 5 parts of silicone-modified polycarbonate were used in Example 5. Evaluation was performed with the same setting as. The results are shown in Table 1.

Example 8 In Example 5, 9.5 parts of the polyarylate resin and the silicone-modified polycarbonate represented by the above formulas (2), (3) and (4) (viscosity average molecular weight Mv = 40,000) were used. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the amount was set to 0.5 part, and the same settings as in Example 1 were evaluated. The results are shown in Table 1.

(Embodiment 9) Auxiliary charging means 8 using a brush-like member as a residual developer uniformizing means as shown in FIG.
The same evaluation as in Example 1 was performed using the electrophotographic apparatus of Example 5 and the electrophotographic photosensitive member of Example 5.

As a member of the auxiliary charging means (residual developer uniformizing means), a conductive rayon brush member is grounded. The results are shown in Table 1.

(Comparative Example 1) An electron was produced in the same manner as in Example 1 except that the polyarylate resin in Example 1 was changed to polycarbonate A (trade name: Teijin Panlite L-1250, manufactured by Teijin Chemicals Ltd.). A photographic photosensitive member was produced and evaluated under the same settings as in Example 1. The results are shown in Table 1.

(Comparative Example 2) An electron was obtained in the same manner as in Example 1 except that the polyarylate resin in Example 5 was replaced with polycarbonate A (trade name: Teijin Panlite L-1250, manufactured by Teijin Chemicals Ltd.). A photographic photosensitive member was produced and evaluated under the same settings as in Example 1. The results are shown in Table 1.

(Comparative Example 3) An electron was prepared in the same manner as in Example 1 except that Polycarbonate A (trade name: Teijin Panlite L-1250, manufactured by Teijin Chemicals Ltd.) was used as the polyarylate resin in Example 2. A photographic photosensitive member was produced and evaluated under the same settings as in Example 1. The results are shown in Table 1.

[0060]

[Table 1]

[0061]

As described above, according to the present invention, it has been a problem until now that the surface layer of an electrophotographic photoreceptor contains a polyarylate resin or a polyarylate resin and a silicone-modified polycarbonate resin at the same time. It has become possible to provide a cleaner-less system electrophotographic apparatus and a process cartridge that can solve the problems of toner fusion and fogging.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a schematic configuration of an electrophotographic apparatus of the present invention having two auxiliary charging means.

FIG. 3 is a diagram showing a layer structure of an electrophotographic photosensitive member.

[Explanation of symbols] 1 Electrophotographic photoreceptor 2 Charging device 3 exposure means 4 Developing device 5 Transfer device 6 Transfer material 7 Auxiliary charging device (developer charge amount control means) 8 Auxiliary charging device (residual developer uniformizing means) S1 to S5 Bias voltage application power supply 11 Support 12 Conductive layer 13 Undercoat layer 14 Charge generation layer 15 Charge transport layer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Haruyuki Tsuji             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Shinji Takagi             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Hiroshi Saito             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2H068 AA03 AA06 BB27 BB33 FA27                       FC01                 2H077 AA37 AC16 AD06 AD13 AD31                       AD35 DB08 GA04                 2H134 GA01 GB02 HF13 KG01 KG03                       KG07 KG08 KH01 MA02 MA11                       MA19                 2H200 FA03 FA08 FA18 GA16 GA23                       GA34 GA44 GA49 GB32 GB37                       HA02 HA28 HB07 HB12 HB22                       HB41 HB48 JA02 JA28 JB10                       NA02 NA06

Claims (8)

[Claims] 1. An electrophotographic photosensitive member, charging means for charging the electrophotographic photosensitive member, information writing means for forming an electrostatic latent image on the electrophotographic photosensitive member that has been subjected to charging processing, and a developer for the electrostatic latent image. And a transfer means for transferring the visualized developer image to a transfer material and a charging means for charging the developer on the surface of the electrophotographic photosensitive member. The developer remaining on the electrophotographic photosensitive member after the transfer step is charged to a normal polarity by the developer charge amount controlling means, and the electrophotography is performed by the charging means. An electrophotographic apparatus which charges a surface of a photoreceptor at the same time as an appropriate amount of charge, wherein the electrophotographic photoreceptor contains a polyarylate resin in a surface layer. 2. An electron after the developer image is transferred to a transfer material, which is located upstream of the developer charge amount control means for charging the developer on the surface of the electrophotographic photosensitive member and downstream of the transfer means. A residual developer image uniformizing means for uniformizing the residual developer image remaining on the surface of the photographic photosensitive member is provided, and the residual developer image remaining on the surface of the electrophotographic photosensitive member after the transfer of the developer image is converted to the residual developer image. The residual developer on the surface of the electrophotographic photosensitive member, which is uniformized by the uniformizing means, is charged to a normal polarity by the developer charge amount controlling means, and the surface of the electrophotographic photosensitive member is charged by the charging means. The electrophotographic apparatus according to claim 1, wherein an appropriate charge amount is set. 3. The electrophotographic apparatus according to claim 1, wherein the charging unit is of a contact charging type and applies an oscillating electric field. 4. The electrophotographic apparatus according to claim 1, wherein the structure of the polyarylate resin is represented by the following formula (1). [Chemical 1] 5. The electrophotographic apparatus according to claim 1, wherein the electrophotographic photosensitive member contains a silicone-modified polycarbonate resin. 6. The electrophotographic apparatus according to claim 5, wherein the silicone-modified polycarbonate resin is a copolymer of structural units represented by the following formulas (2), (3) and (4). [Chemical 2] 7. The electrophotographic apparatus according to claim 5, wherein the surface layer of the electrophotographic photosensitive member contains a silicone powder lubricant. 8. The electron according to claim 1, wherein the electrophotographic photosensitive member and at least one unit selected from the group consisting of a charging unit, an auxiliary charging unit and a developing unit are integrally supported. A process cartridge that is removable from the main body of the photographic device.