JPH1097118A - Electrifying member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly electrify a photosensitive surface and to prevent deterioration of the quality of an output image. SOLUTION: An elastic layer 102 having medium resistance is formed around a conductive supporting body 101, and further a surface layer 103 containing polyaminoamide epichlorohydrin resin is formed. The electric resistance of the medium resistance elastic layer 102 is controlled to the range from 10<7> to 10<9> Ω.cm. By using the electrifying member 100 thus produced, contamination on the roller surface can be decreased and the photosensitive surface can be uniformly electrified. Thus, a good output image can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging member, and more particularly, to a charging member for charging an image carrier of an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus, a corona discharger has been widely used as a charging method for uniformly charging the entire surface of an image bearing member (photosensitive member).
However, corona dischargers generate harmful substances such as ozone. For this reason, harmful substances are collected by a filter or the like. However, if used for a long time, the collection efficiency of the filter decreases. In addition, it is necessary to replace the filter periodically.

In order to avoid such a problem, a charging method (contact charging method) that does not use a corona discharger has been proposed. For example, JP-A-58-1391
In the method described in Japanese Patent Application Laid-Open No. 56-178267 and Japanese Patent Application Laid-Open No. 57-178267, charging is performed by bringing a brush-shaped charger into contact with the surface of the photoreceptor. Also, Japanese Patent Application Laid-Open No. Sho 56-10435
In the system described in Japanese Patent Application Publication No. 1 (1999), a charging belt is employed, and charging is performed by bringing the charging belt into contact with a photosensitive member. Further, in the method described in Japanese Patent Application Laid-Open No. 58-40566, a fibrous electrode is used in order to further suppress ozone generation.

In this type of contact charging system, the applied voltage can be reduced as compared with the corona charging system (1 to 2).
KV), the generation of ozone can be suppressed.

[0005]

However, according to the above-mentioned prior art, when charging is continuously performed in a copying machine or the like, toner particles pass through the cleaning unit and become residual toner particles, which adhere to the surface of the charging roller. When the residual toner particles adhere to the surface of the charging roller due to a filming phenomenon, the surface of the charging roller is electrically insulated. There is a problem that the temperature is significantly reduced.

In particular, in the case of regular development, white streak-like image unevenness occurs in an output image, and in the case of reversal development generally used in laser printers and the like, black streak-like image unevenness occurs in an output image. Was.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and prevents the residual toner particles from sticking to the charging member, uniformly charges the surface of the photoreceptor, and prevents the quality of the output image from deteriorating. The purpose is to:

[0008]

According to a first aspect of the present invention, there is provided a charging member according to the first aspect, wherein at least one intermediate layer provided on an outer periphery of the conductive support, and an outer periphery of the intermediate layer. Wherein the surface layer contains a polyaminoamide / epichlorohydrin resin.

According to a second aspect of the present invention, there is provided a charging member comprising: an elastic layer provided on an outer periphery of a conductive support; and a surface layer provided on an outer periphery of the elastic layer. The surface layer contains a polyaminoamide / epichlorohydrin resin, and the elastic layer is a medium resistance elastic layer.

The charging member according to claim 3 is the charging member according to claim 2, wherein the medium-resistance elastic layer is
It has an electrical resistance in the range of 10 ⁷ to 10 ⁹ Ω · cm.

According to a fourth aspect of the present invention, there is provided a charging member comprising: an elastic layer provided on an outer periphery of a conductive support; and a surface layer provided on an outer periphery of the elastic layer. The surface layer contains a polyaminoamide / epichlorohydrin resin, and the elastic layer is a conductive elastic layer.

According to a fifth aspect of the present invention, in the charging member according to the fourth aspect, the conductive elastic layer comprises:
It has an electric resistance of 10 ⁴ Ω · cm or less.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The charging member of the present invention will be described below with respect to [Example of shape and configuration of charging member of the present invention], [Configuration example of electrophotographic apparatus], [First Embodiment], Embodiment 2], [Comparative Examples 1 to 3], [Embodiment 3], [Embodiment 4], and [Comparative Example 4] will be described in detail with reference to the drawings. The present invention is not limited by the embodiment.

[Shape and Configuration Example of Charging Member of the Present Invention] FIG. 1 is a sectional configuration diagram showing a first example of the shape of the charging member of the present invention. The charging member 100 is in the form of a roller, and has a conductive support 101 in the form of a metal core,
It comprises a middle resistance elastic layer 102 which is an intermediate layer provided around the conductive support 101, and a surface layer 103 formed on the outer peripheral surface of the middle resistance elastic layer 102.

FIG. 2 is a sectional view showing a second example of the shape of the charging member of the present invention. The charging member 200 is in the form of a roller, and has a conductive support 1 in the form of a cored bar.
01, a conductive elastic layer 104 which is an intermediate layer provided around the conductive support 101, and a surface layer 103 formed on the outer peripheral surface of the conductive elastic layer 102.

In order to improve the adhesiveness, a primer layer may be provided between the layers shown in FIGS. For example, the surface of the conductive support 101 may be treated with a conductive primer such as synthetic rubber mixed with a conductive substance such as carbon black.

Further, as the conductive support 101, iron,
Metals such as stainless steel and aluminum, and conductive resins such as carbon black dispersed resin and metal particle dispersed resin can be used.

The medium resistance elastic layer 102 has an electric resistance of 1
If the range of 0 ⁷ ~10 ⁹ Ω · cm good results. As a material for the medium resistance elastic layer 102, polar rubbers such as epichlorohydrin rubber, urethane rubber, chloroprene rubber, and acrylic rubber can be used as a raw material rubber. Epichlorohydrin rubber is preferred because of its low environmental dependency.

The raw rubber for epichlorohydrin includes homopolymers of epichlorohydrin, copolymers of epichlorohydrin and ethylene oxide, copolymers of epichlorohydrin and allyl glycidyl ether, and ternary copolymers of epichlorohydrin, ethylene oxide and allyl glycidyl ether. Although there is a polymer (hereinafter referred to as GECO), GECO is preferred because it has a relatively low electric resistance, has little environmental dependence of electric resistance, and has a very small increase in electric resistance due to energization.

The surface layer 103 is formed of a resin layer containing a polyaminoamide / epichlorohydrin resin (hereinafter, referred to as a PAE resin). PAE resin is used as a sizing agent for paper and is used as a polymer to increase the wet resistance of paper. This PAE resin is a known material, and is disclosed in U.S. Pat. No. 2,926,116 and U.S. Pat.
No. 87510 discloses this.

The PAE resin is a water-soluble resin obtained by obtaining a water-soluble polyamino amide by primary synthesis by a condensation reaction of a dibasic ester and ethylenetriamine, and subjecting this linear polymer to a condensation reaction with epichlorohydrin. And is thermosetting. Its molecular structure is shown in Chemical Formula 1.

[0022]

Embedded image

The reason that the surface layer 103 contains a PAE resin is that the PAE resin was found to have excellent non-adhesiveness. The use of the PAE resin can effectively prevent the toner particles from sticking to the surface of the charging member.
Therefore, stable charging characteristics can be obtained. As a result, good image quality can be maintained for a long period of time.

The PAE resin has an electric resistance of 10 ¹⁰ Ω ·
cm and a medium resistance region. For this reason, it is not necessary to add an adjusting material such as conductive particles, which is suitable as a surface material of the charging member. Further, the electric resistance value in the surface layer 103 can be made uniform, and the charging unevenness can be extremely reduced.

In order to adjust the hardness of the surface layer 103, an inorganic filler such as silica may be added. Also,
Since the PAE resin is a water-soluble resin, it is preferable from the viewpoint of suppressing the emission of organic solvents in recent years.

The conductive elastic layer 104 has an electric resistance of 1
0 ⁴ Ω · cm when the following range good results are obtained. The conductive elastic layer 104 is made of carbon black,
It is formed by dispersing low-resistance particles such as metal oxides and metal powders and using a rubber material adjusted to be conductive. Rubber materials include nitrile rubber, chloroprene rubber, ethylene propylene / diene copolymer rubber (hereinafter referred to as EPDM), silicone rubber, urethane rubber, natural rubber, epichlorohydrin rubber, acrylic rubber, styrene / butadiene rubber, acrylonitrile / butadiene rubber. , A crosslinked rubber such as a hydrogenated nitrile rubber, and copolymers and mixtures thereof.

[Structural Example of Electrophotographic Apparatus] FIG. 3 is a structural view showing an electrophotographic apparatus 300 using the charging member 100 (or 200) of the present invention. A DC voltage power source 302 for applying a bias voltage is connected to the conductive support 101 of the charging member 100 (or 200) to form a charging device. Also, the charging member 100 (20
No. 0) is disposed in contact with a drum-shaped electrophotographic photosensitive member 303 which is an organic photosensitive member (OPC).

On the peripheral surface of the electrophotographic photosensitive member 303, a charging member 100 (200), an image exposing device (not shown), a developing unit 304, and a transfer charging device 305 are provided.
, A cleaning device 306 and a pre-exposure device (not shown). In the drawing, reference numeral 307 denotes exposure light emitted from the image exposure device, 308 denotes pre-exposure light of the pre-exposure device, and 309 denotes a member to be transferred such as paper.

First, a voltage (for example, -1400 V) is applied to the conductive support 101 of the charging member 100 (200) by the DC voltage power supply 302, and the electrophotographic photosensitive member 303
Then, the image on the original is image-exposed on the electrophotographic photosensitive member 303 by an image exposure device to form an electrostatic latent image.

Next, the electrostatic latent image on the electrophotographic photosensitive member 303 is developed by attaching the developer in the developing unit 304 to the electrophotographic photosensitive member 303. Subsequently, the developer on the electrophotographic photosensitive member 303 is transferred to a transfer member 309 such as paper by the transfer charging device 305. The cleaning device 306 does not transfer the image to the paper at the time of the transfer.
The developer remaining in 03 is collected. If residual charge remains on the electrophotographic photosensitive member 303, the charging member 1
It is better to remove residual charges by a pre-exposure device before performing primary charging by 00 (200).

[Embodiment 1] In Embodiment 1, the charging member 100 is manufactured by the following method. Conductive support 1
The medium resistance elastic layer 102 was formed by the following composition and processing method using a stainless steel core of φ8 mm as 01.

GECO-based epichlorohydrin raw rubber (trade name: Epichroma CG102, manufactured by Daiso) 100 parts by weight Calcium carbonate (trade name: Tamapearl TR-222H, manufactured by Okutama Kogyo) 30 parts by weight 10 parts by weight Stearic acid 0.5 part by weight Vulcanization accelerator (trade name: Noxera TT, manufactured by Ouchi Shinko Chemical) 1.0 part by weight Vulcanization accelerator (trade name: Noxera DM, Ouchi Shinko Chemical) 1.5 parts by weight Vulcanization accelerator (trade name: Barnock R, manufactured by Ouchi Shinko Chemical) 1.0 part by weight Vulcanizing agent (trade name: Sulfax, manufactured by Tsurumi Chemical) 0.25 parts by weight

The composition ratio of Epichroma CG102 is as follows:
Epichlorohydrin 40 mol%, ethylene oxide 5
3 mol% and allyl glycidyl ether 7 mol%.

After kneading the above-mentioned compound to form a compound having a uniform composition, a primary vulcanization (150 ° C. × 15 minutes) and a secondary vulcanization (150 ° C. × 15 minutes) are carried out on a φ8 mm stainless steel core (conductive support 101). (155 ° C x 7 hours)
A roller-shaped medium resistance elastic layer 102 was formed to have a size of mm × 310 mm. The electric resistance of the medium resistance elastic roller was 2 × 10 ⁷ Ω · cm, and the roller rubber hardness was 38 degrees (JisA).

The electric resistance of the medium-resistance elastic roller was measured by measuring the medium-resistance elastic roller at 20.degree. H. After being left in the environment for 16 hours, a copper foil tape (trade name: Scotch No. 1181, manufactured by 3M) having a width of 25.4 mm was wound around the circumference of the medium resistance elastic roller to form an electrode. A DC voltage of 500 V was applied between the metal core and the electrode, and a current value one minute after the application was measured to determine a volume resistance value. The rubber hardness of the medium resistance elastic roller was measured by JisK.
Using a hardness meter JisA described in No. 6301, measurement was performed by applying pressure perpendicular to the center axis direction of the medium resistance elastic roller.

Next, the surface layer 1 is placed on the medium resistance elastic roller.
03 was formed as follows. First, the paint for the surface layer was prepared as follows. To 100 parts by weight of PAE resin (trade name: Harmide PY-410, manufactured by Harima Chemicals), 56 parts by weight of city water (PH6.8) was added, and the mixture was sufficiently stirred to obtain a coating for the surface layer (resin solid content: 8%). .

After the surface layer paint was applied by dip coating on the medium resistance elastic roller, the coating was cured at 120 ° C. for 2 hours to form a surface layer 103 having a thickness of 10 μm. This surface layer 10
The electrical resistance of No. 3 was 2 × 10 ¹⁰ Ω · cm.

The electric resistance of the surface layer 103 was measured by coating the surface layer on an aluminum plate (0.2 mm thick) with a thickness of about 100 μm.
m, a sample coated at 20 ° C., 60% R.M. 1 in H environment
After standing for 6 hours, a resistance measuring cell (trade name: 16008)
A, manufactured by YHP) and a resistance meter (trade name: R8340A, manufactured by Advantest) at an applied voltage of 100 V.

The charging member 10 manufactured as described above
No. 0 (charging roller) was attached instead of the primary corona charger of a regular development type copying machine (trade name: Ricoh FT3350, manufactured by Ricoh Co., Ltd.), and was driven to rotate following contact with the OPC drum surface. DC voltage -1 as primary charging voltage
400 V, 24 ± 1 ° C., 50-55% R. Operate continuously in H environment, start, 10,000 sheets, 20
000 sheets, 30000 sheets, 40000 sheets (A3 size)
The potential measurement of the dark potential of the OPC, the contamination state of the charging roller surface, and the image quality were evaluated for each OPC.

Table 1 shows the results of the evaluation. The state of contamination of the surface of the charging roller with toner and the like was evaluated according to the following criteria. : Slight toner and the like adhered, but the adhered matter on the roller surface can be easily wiped off with a cloth or the like. : A slight amount of toner or the like remains on the roller surface after wiping. : Complete wiping was not possible, and a thin film of toner remained on the roller surface. : The toner and the like are strongly adhered to the roller surface.

[0041]

[Table 1]

[Second Embodiment] A medium resistance elastic roller according to the second embodiment is similar to the medium resistance elastic layer 1 of the first embodiment.
GECO-based epichlorohydrin raw rubber (trade name: Epichroma CG102: manufactured by Daiso Co., Ltd.)
Was manufactured in the same manner as in Embodiment 1 except that GECO-based epichlorohydrin raw rubber (trade name: Epichroma CG108, manufactured by Daiso) having a different composition ratio was used.

The composition ratio of this epichroma CG108 is epichlorohydrin 63 mol%, ethylene oxide 31 mol%, and allyl glycidyl ether 6 mol%. The electric resistance of the medium resistance elastic roller is 3 × 10
It was ⁹ Ω · cm.

Next, the surface layer 1 is placed on the medium resistance elastic roller.
03 was formed in the same manner as in the first embodiment. Surface layer 10
The thickness of No. 3 was 10 μm.

Table 1 shows the evaluation results of the charging roller manufactured as described above in the same manner as in the first embodiment.

[Comparative Example 1] As Comparative Example 1, a medium-resistance elastic roller in which the surface layer 103 of Embodiment 1 was not applied was manufactured. Table 1 shows the results of evaluation of this medium resistance elastic roller in the same manner as in Embodiment 1.

[Comparative Example 2] As Comparative Example 2, a medium resistance elastic roller was prepared by adding carbon black (trade name: Black Pearls L, manufactured by Cabot Corporation) to the material composition of the medium resistance elastic layer 102 of the first embodiment. 0.0 parts by weight,
It was manufactured in the same manner as in the first embodiment.

The electric resistance of this medium resistance elastic roller is 3 × 1
0 ⁶ Ω · cm, the roller hardness was 40 degrees. The surface layer 103 was formed on the medium resistance elastic roller in the same manner as in the first embodiment. The thickness of the surface layer 103 was 10 μm.

Table 1 shows the evaluation results of the charging roller manufactured as described above in the same manner as in the first embodiment.

[Comparative Example 3] As Comparative Example 3, a medium-resistance elastic roller was manufactured by using a raw material rubber of GECO-based epichlorohydrin (trade name: Epichroma CG102, Daiso Co., Ltd.) Was manufactured in the same manner as in Embodiment 1 except that the raw material of the copolymer of epichlorohydrin and ethylene oxide (ECO; trade name: Epichroma CG, manufactured by Daiso) was used instead of E.g.

The composition ratio of this epichroma CG was 49 mol% of epichlorohydrin and 51 mol of ethylene oxide.
mol%. The electric resistance of the medium resistance elastic roller was 4 × 10 ¹⁰ Ω · cm.

Next, the surface layer 1 is placed on the medium resistance elastic roller.
03 was formed in the same manner as in the first embodiment. The thickness of the surface layer was 10 μm.

Table 1 shows the evaluation results of the charging roller manufactured as described above in the same manner as in the first embodiment.

Consideration is made from Table 1 above. First, there is a marked difference between the first embodiment and the comparative example 1 in the state of contamination on the surface of the charging roller depending on whether or not the surface layer 3 is provided. When the surface layer 103 is provided, in the range from the start to 40,000 sheets, the level is such that "a slight amount of toner or the like adheres to the surface of the charging roller, but the attached matter on the roller surface can be easily wiped off with a cloth or the like." (Reference). However, when the surface layer 103 was not provided, in the same range, the level (reference) was lower than the reference, and "the toner or the like was strongly fixed to the roller surface".

Next, the charging potential is compared between the first embodiment and the first comparative example. In Comparative Example 1, the charging potential decreased as the number of sheets increased, and the charging became completely insufficient from 20,000 sheets. On the other hand, in Embodiment 1, the charging potential was stable even when the number of sheets was increased. This indicates that if the surface of the charging roller is extremely contaminated (Comparative Example 1), the charging becomes insufficient.

Next, regarding the presence / absence of an abnormal image, it does not occur in the first embodiment.
From the time of 000 sheets, the image density became low, and streaky unevenness increased.

From this, it can be seen that the surface layer 103 works effectively for preventing contamination of the surface of the charging roller and preventing occurrence of abnormal images. In particular, when a resin containing a polyaminoamide / epichlorohydrin resin is used for the surface layer 103, the non-adhesiveness to the toner increases, and the charging characteristics are maintained for a long time. As a result, occurrence of an abnormal image can be effectively prevented.

(2) Next, when the first and second embodiments are compared with the comparative examples 2 and 3, first, the electric resistance of the medium resistance elastic roller of the first embodiment is 2 ×
10 ⁷ Ω · cm, and the electric resistance of the medium resistance elastic roller of the second embodiment is 3 × 10 ⁹ Ω · cm. On the other hand, the electrical resistance of Comparative Example 2 was 3 × 10 ⁶ Ω · cm,
It is smaller than in the first embodiment. The electric resistance of Comparative Example 3 is 4 × 10 ¹⁰ Ω · cm, which is larger than that of Embodiment 2.

According to the comparison results, the contamination state of the charging roller surface is good in any case. Further, with respect to the charging potential, the comparative examples 2 and 3 have some variation.

However, looking at the presence or absence of an abnormal image,
In the first and second embodiments, no abnormal image was generated. In contrast, in the comparative example 2, the image density was uneven from the start, and in the comparative example 3, the image density was decreased from the start. From this, it was found that by setting the electric resistance (2 × 10 ⁷ Ω · cm to 3 × 10 ⁹ Ω · cm) as in the embodiment, generation of an abnormal image can be prevented.

[Embodiment 3] In Embodiment 3, a charging member is manufactured by the following method. A conductive elastic layer 104 was formed by the following composition and processing method using a stainless steel core of φ8 mm as the conductive support 101.

EPDM raw rubber (trade name: Esplen, manufactured by Sumitomo Chemical) 100 parts by weight Carbon black (trade name: Black Pearls L, manufactured by Cabot) 13 parts by weight Hydrocarbon synthetic oil (trade name: Lucant HC-100, Mitsui) Petrochemical) 15 parts by weight Zinc flower (trade name: special name, manufactured by Shodo Chemical) 5 parts by weight Stearic acid 1 part by weight Vulcanization accelerator (trade name: Succinol BZ, manufactured by Sumitomo Chemical) 2.0 parts by weight 0.5 parts by weight of vulcanization accelerator (trade name: Succinol TT, manufactured by Sumitomo Chemical) 0.5 parts by weight vulcanization accelerator (trade name: Succinol M, manufactured by Sumitomo Chemical) 1.0 parts by weight Vulcanizing agent (trade name: Sulfax, manufactured by Tsurumi Chemical) 1.0 part by weight

After kneading the above compound to form a compound having a uniform composition, a primary vulcanization (155 ° C. × 15 minutes) and a secondary vulcanization (160 ° C.) were performed on a stainless steel core bar of φ8 mm (conductive support 101). ° C × 5 hours), outer diameter φ14m
m × 310 mm, roller-shaped conductive elastic layer 1
04 was provided. The electric resistance of this conductive elastic roller is 2 ×
10 ⁴ Ω · cm, and the roller rubber hardness was 37 degrees.

The surface layer 10 on the conductive elastic roller described above
The formation of No. 3 is the same as that of Embodiment 1 except that the total amount of 56 parts by weight of city water (PH 6.8) is deleted (resin solid content: 12.5%) in the composition of the coating material for the surface layer of Embodiment 1. Coating and drying were performed in the same manner as in Example 1. The thickness of the surface layer 103 was 250 μm.

Table 2 shows the evaluation results of the charging roller manufactured as described above in the same manner as in the first embodiment.

[0066]

[Table 2]

[Embodiment 4] Embodiment 4 is different from Embodiment 3 in that the addition amount of carbon black is changed to 18 parts by weight in the composition of the conductive elastic layer 104 of Embodiment 3. Similarly, it was produced similarly. The electric resistance of this conductive elastic roller was 1 × 10 ² Ω · cm, and the roller rubber hardness was 40 degrees.

Next, the surface layer 1 is placed on the conductive elastic roller.
03 was formed in the same manner as in the third embodiment. This surface layer 10
3 had a thickness of 240 μm.

Table 2 shows the evaluation results of the charging roller manufactured as described above in the same manner as in the first embodiment.

Comparative Example 4 As Comparative Example 4, the conductive elastic roller of Embodiment 3 was replaced with the conductive elastic layer 104 except that the addition amount of carbon black was changed to 8 parts by weight. It was manufactured in the same manner as the third embodiment.

The electric resistance of this conductive elastic roller was 5 × 10 ⁵ Ω · cm, and the roller rubber hardness was 36 degrees. The surface layer 103 was formed on the conductive elastic roller in the same manner as in the third embodiment. The thickness of the surface layer 103 was 250 μm.

Table 2 shows the evaluation results of the charging roller manufactured as described above in the same manner as in the first embodiment.

Consideration is made from Table 2 above. Embodiment 3
Comparing Embodiment 4 with Comparative Example 4, first, the electric resistance of the conductive elastic roller of Embodiment 3 is 2 ×
10 ⁴ Ω · cm, and the electric resistance of the conductive elastic roller of the fourth embodiment is 1 × 10 ² Ω · cm. On the other hand, the electrical resistance of Comparative Example 4 was 5 × 10 ⁵ Ω · cm,
It is larger than the third and fourth embodiments.

From the comparison results, the state of contamination on the surface of the charging roller is good in any case and indicates the standard. Also, the charging potential is relatively stable.

However, looking at the presence or absence of an abnormal image,
In the third and fourth embodiments, no abnormal image was generated, whereas in the comparative example 4, the image density was uneven from the beginning. From this, it was found that occurrence of an abnormal image can be prevented by setting the electric resistance (2 × 10 ⁴ Ω · cm or less) as in the third and fourth embodiments.

The surface layer 103 is made of polyaminoamide.
Since the resin containing the epichlorohydrin resin is used, the non-adhesiveness to the toner is increased, and the charging characteristics are maintained for a long time. As a result, occurrence of an abnormal image can be effectively prevented.

[0077]

As described above, according to the charging member of the present invention (claim 1), the surface layer of the charging member contains a polyaminoamide / epichlorohydrin resin. The non-adhesiveness to the toner increases, and the toner hardly remains on the surface of the charging member. As a result, the photosensitive member surface can be uniformly charged,
Deterioration of the quality of the output image is prevented. In other words, the non-adhesiveness of the charging member surface to the toner can be improved, and the durability of the charging member can be improved.

According to the charging member of the present invention (claim 2), the surface layer contains a polyaminoamide / epichlorohydrin resin and the elastic layer is a medium-resistance elastic layer. In addition to improving the non-adhesion of the charging member, the durability of the charging member can be improved, a uniform charging process can be performed, and the durability of the charging member can be significantly improved.

Further, according to the charging member of the present invention (claim 3), the electric resistance of the medium resistance elastic layer is 10 ⁷ to 10 ⁹ Ω ·
cm, a more uniform charging process can be performed, and the durability of the charging member can be significantly improved.

According to the charging member of the present invention (claim 4), the surface layer contains a polyaminoamide / epichlorohydrin resin and the elastic layer is a conductive elastic layer. In addition to improving the non-adhesion of the charging member, the durability of the charging member can be improved, a uniform charging process can be performed, and the durability of the charging member can be significantly improved.

According to the charging member of the present invention (claim 5), the electric resistance of the conductive elastic layer is set to a range smaller than 10 ⁴ Ω · cm, so that a more uniform charging process can be performed. The durability of the charging member can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a sectional configuration view showing a first example of a shape of a charging member of the present invention.

FIG. 2 is a sectional view showing a second example of the shape of the charging member of the present invention.

FIG. 3 is a configuration diagram showing an electrophotographic apparatus using the charging member of FIG. 1 or 2;

[Explanation of symbols]

 REFERENCE SIGNS LIST 100, 200 charging member 101 conductive support 102 medium resistance elastic layer 103 surface layer 104 conductive elastic layer

Claims (5)

[Claims] 1. A charging member having at least one intermediate layer provided on an outer periphery of a conductive support and a surface layer provided on an outer periphery of the intermediate layer, wherein the surface layer comprises:
A charging member comprising a polyaminoamide / epichlorohydrin resin. 2. A charging member having an elastic layer provided on an outer periphery of a conductive support and a surface layer provided on an outer periphery of the elastic layer, wherein the surface layer is made of a polyaminoamide / epichlorohydrin resin. A charging member, wherein the elastic layer is a medium-resistance elastic layer. 3. The charging member according to claim 2, wherein said medium resistance elastic layer has an electric resistance in a range of 10 ⁷ to 10 ⁹ Ω · cm. 4. A charging member having an elastic layer provided on an outer periphery of a conductive support and a surface layer provided on an outer periphery of the elastic layer, wherein the surface layer is made of a polyaminoamide / epichlorohydrin resin. A charging member, wherein the elastic layer is a conductive elastic layer. 5. The charging member according to claim 4, wherein the conductive elastic layer has an electric resistance of 10 ⁴ Ω · cm or less.