JP5561518B2 - Semiconductive member for electrophotography and electrophotographic apparatus using them - Google Patents

Description

  The present invention relates to an electrophotographic conductive member such as a transfer member and a charging member used in an image forming apparatus that forms an image by an electrophotographic system such as a copying machine, a printer, and a facsimile.

  Various electroconductive materials are used in electrophotographic image forming apparatuses. In particular, as a semiconductive material used as a transfer belt, a thermoplastic resin and a thermosetting resin have been conventionally used. In order to suppress the adverse effect of image quality, it is desirable that the dependency of the resistivity of the transfer belt material is small on the applied bias. In order to reduce the applied bias dependency, it is necessary to uniformly and finely disperse the conductive material such as carbon black to be added. For these reasons, it is common to use a thermosetting resin such as polyamide or polyamideimide capable of controlling the dispersion of carbon black in a low-viscosity solution state for a high-quality transfer belt. However, in recent years, reduction of CO2 emission to the global environment has been desired more than before, and thermosetting resins must use organic solvents and cannot be continuously produced or recycled. Environmental load such as CO2 emissions is large. On the other hand, thermoplastic resins typified by polyvinylidene fluoride resins have the advantage that they can be produced continuously, can reduce the environmental burden during manufacturing, and are easy to recycle. However, the dispersion of the conductive material such as carbon black is not easy as compared with the thermosetting resin, and there is a drawback that the bias dependency of the resistivity becomes large.

  Conventionally, there are semiconducting members used for various purposes in electrophotographic apparatuses, for example, semiconducting members such as a belt member, a conveying roll member, and a charging sheet member. An intermediate transfer belt system is used in which the toner image thus transferred is temporarily transferred onto an intermediate transfer medium and then transferred onto a transfer medium such as paper. At that time, in a full-color electrophotographic apparatus, an intermediate transfer belt that temporarily superimposes developed images of four colors of yellow, magenta, cyan, and black on an intermediate transfer medium and then collectively transfers them onto a transfer medium such as paper. The method is used.

  For example, Japanese Patent Application Laid-Open No. 2008-291098 of Patent Document 1 discloses a belt member obtained by adding carbon black and an ionic conductive agent to polyvinylidene fluoride. In this technology, since polyvinylidene fluoride is difficult to disperse carbon, there is a problem that it is difficult to control the resistance value and it is difficult to obtain uniformity. Therefore, by adding an ionic conductive agent, a desired volume resistance can be obtained. Values are made stable and uniform. However, since an ionic conductive agent is used, there is a problem that resistance change due to the environment is large.

  Japanese Patent Application Laid-Open No. 2006-313308 of Patent Document 2 describes an electrophotographic belt member having a sea-island structure composed of a matrix phase of polyvinylidene fluoride in which carbon is dispersed and a domain phase of a resin such as polyetheresteramide. Yes. In this technique, since polyvinylidene fluoride is difficult to disperse carbon, unless it is added in large amounts, charge transfer between the carbons is not performed quickly, and the static elimination performance becomes insufficient. In this case, there is a problem that the image density repeatedly becomes unstable. Therefore, by causing a resin such as polyetheresteramide dispersed in islands to enter between the carbons, charge transfer is accelerated. It aims to improve the static elimination performance. However, since the volume resistance value of the belt material is governed by the dispersion state and addition amount of carbon, the stability and uniformity are not sufficiently improved.

Generally, it can be achieved by increasing the amount of heat and shear energy input when dispersing a conductive material such as carbon black in a thermoplastic resin, thereby uniformly and finely dispersing the conductive material such as carbon black. In the case of a thermoplastic resin, the polymer chain is broken or the conductive fine particles penetrate into the crystal region, thereby causing a decrease in the tensile elastic modulus and Tg of the semiconductive material. When actually incorporated in an image forming apparatus and used, it causes quality problems due to belt elongation, creep, and the like.
On the other hand, when priority is given to maintaining the tensile elastic modulus, the uniformity of conductivity is impaired. Therefore, when used as a transfer belt, there arises a problem that image defects such as blur and white spots occur.

  The present invention has been made in view of the above prior art, and in particular, a conductive powder material such as carbon black is uniformly and well dispersed, has excellent strength and elongation resistance, and has electrical characteristics, particularly resistivity. An object of the present invention is to provide a semiconductive member for an electrophotographic apparatus that is less dependent on an applied bias, has less cracks and scratches, is excellent in durability, and is suitable for forming a high-quality image, and an electrophotographic apparatus using the same. To do.

In general, thermoplastic resin materials cannot be said to have sufficient affinity for conductive fine particles, and in particular, the tendency of the resin having higher repellency such as fluorine resin and silicone resin is more remarkable. As a result of intensive studies, the present inventors have determined that when finely dispersing the conductive fine particles in such a thermoplastic resin, the conductive fine particles are not directly melt-kneaded in such a thermoplastic resin. Resin materials, ie, urea residues (—NH · CO · NH—), thiourea residues (—NH · CS · NH—), thiocarbamoyl residues (—NH · CS · O—), carbamoyl residues (— NH.CO.O-), a conductive fine particle-containing resin composition obtained by dispersing conductive fine particles in a resin material having a sulfonylamide residue (-SO ₂ NH-) site, and kneading with a thermoplastic resin To do More, it found that the object of the present invention is smoothly and completely achieved, and completed the present invention by promoting the further study.
As described above, when a conductive material such as carbon black is melt-kneaded and dispersed in a thermoplastic resin, a slightly harder molten resin material in a state where the melt viscosity is slightly lowered (a state where excessive high temperature is avoided) By sufficiently deforming the material such as rolling, the aggregate of fine particles firmly held in the resin plastic material is accompanied by the deformation of the resin material, and the secondary particles such as shredder are sufficiently unwound. Therefore, by applying a great amount of shear energy, the polymer chain of the thermoplastic resin is broken or the conductive fine particles penetrate into the crystalline region, and the tensile modulus of elasticity of the semiconductive material Although this will cause a decrease in Tg, the present invention can avoid this. This is because the specific resin material has a strong polar group portion as described above and a hydrocarbon portion portion having an affinity for a thermoplastic resin at the same time. It is also imagined that this is because a good polymer blend can be formed with a plastic resin. However, this hypothesis should not affect the actual effect and technical scope of the present invention.

Thus, the above object is preferably solved by the present invention described below.
(1) “The resin composition (α) in which conductive fine particles are dispersed is blended with a thermoplastic resin to form a sea-island structure in which the resin composition (α) is dispersed in a thermoplastic resin matrix. When the resistivity is 10 ⁵ to 10 ¹⁰ (Ω · cm), the volume resistivity when a bias of 10V is applied is ρv10, and the volume resistivity when a bias of 500V is applied is ρV500,
0 ≦ Log (ρv10) −Log (ρv500) ≦ 1 is satisfied, and the resin composition (α) has one of the following linking groups in the main chain or the subchain: Semiconductive member for photography.

（２）「前記熱可塑性樹脂がポリフッ化ビニリデン系樹脂であることを特徴とする前記（１）項に記載の電子写真用半導電性部材。」；
（３）「前記導電性微粒子がカーボンブラックであることを特徴とする前記（１）項又は（２）項に記載の電子写真用半導電性部材。」；
（４）「前記（１）項乃至（３）項のいずれかに記載の電子写真用半導電性部材を備えたことを特徴とする電子写真装置。」；
（５）「前記電子写真用半導電性部材が、像担持体に接触して設けられた転写用ベルトであることを特徴とする、前記（４）項に記載の電子写真装置。」；
（６）「前記電子写真用半導電性部材が、像担持体と転写用ベルトの接触部において、転写用ベルトの裏面に押圧して設けられた転写用シート部材であることを特徴とする、前記（４）項に記載の電子写真装置。」；
（７）「前記電子写真用半導電性部材が、像担持体に押圧して設けられた帯電用シート部材であることを特徴とする、前記（４）項に記載の電子写真装置。」。

(2) “The electroconductive semiconductive member as described in (1) above, wherein the thermoplastic resin is a polyvinylidene fluoride resin”;
(3) “The electroconductive semiconductive member according to item (1) or (2), wherein the conductive fine particles are carbon black”;
(4) “An electrophotographic apparatus comprising the electroconductive semiconductive member according to any one of (1) to (3)”;
(5) "The electrophotographic apparatus according to (4), wherein the electrophotographic semiconductive member is a transfer belt provided in contact with an image carrier";
(6) "The electrophotographic semiconductive member is a transfer sheet member provided by being pressed against the back surface of the transfer belt at a contact portion between the image carrier and the transfer belt. The electrophotographic apparatus according to (4) above ”;
(7) The electrophotographic apparatus according to (4), wherein the electrophotographic semiconductive member is a charging sheet member provided by being pressed against an image carrier.

As will be apparent from the following detailed and specific description, according to the present invention, excellent physical properties (chemical resistance, wear resistance, piezoelectricity) of thermoplastic resins such as polyvinylidene fluoride resins can be obtained. An electrophotographic semiconductive member that is excellent in electrical characteristics while being maintained can be obtained.
That is, it is possible to simultaneously improve the tensile modulus and the dispersion uniformity of carbon black. In particular, when used as a transfer belt member in an image forming apparatus, a stable transfer performance can be maintained over a long period of time without causing belt deformation or breakage, so that a high-quality image free from blur and white spots can be obtained. Can do.

1 is a diagram illustrating an example of an image forming apparatus using an electrophotographic semiconductive member of the present invention as an intermediate transfer belt.

[Image forming apparatus]
First, an example of an image forming apparatus using the electrophotographic semiconductive member to which the present embodiment is applied will be described.
FIG. 1 is a schematic diagram illustrating a configuration of a color image forming apparatus to which the exemplary embodiment is applied.
Each process cartridge unit (1) has a structure in which a photosensitive drum (2), a charging roller (3), a developing means (4), and a cleaning means (5) are integrally coupled. Each process cartridge unit (1) can be replaced by releasing each stopper.

The photosensitive drum (2) rotates in the direction of the arrow. The charging roller (3) is in pressure contact with the surface of the photosensitive drum (2), and is rotated by the rotation of the photosensitive drum (2).
A bias voltage is applied to the charging roller (3) by a high voltage power source (not shown) to charge the surface of the photosensitive drum (2) so as to have a desired surface potential.
The exposure means (6) exposes image information to the photosensitive drum (2) and forms an electrostatic latent image by partially changing the surface potential. A laser beam scanner or LED using a laser diode is used for the exposure means (6).

The developing means (4) is one-component contact development, and a predetermined developing bias is supplied from a high voltage power source (not shown). The developing means (4) forms a toner image by adhering toner that has been frictionally charged in accordance with the electrostatic latent image on the photosensitive drum (2).
The photoreceptor cleaning means (5) cleans the transfer residual toner on the surface of the photoreceptor drum (2).
Four process cartridge units (1) are arranged in parallel in the moving direction of the intermediate transfer belt (7), and form visible images in the order of yellow, cyan, magenta, and black.
A primary transfer bias is applied to the primary transfer roller (8), and the toner image on the surface of the photosensitive drum (2) is transferred to the surface of the intermediate transfer belt (7). The intermediate transfer belt (7) is driven to rotate in the direction of the arrow in the figure by a drive motor (not shown), and a full color image is formed by sequentially transferring the visible images of the respective colors onto the surface.

The formed full color image is transferred to a sheet (10) as a transfer material by applying a predetermined voltage to the secondary transfer roller (9), and is fixed and output by a fixing device (not shown). The toner that cannot be transferred by the secondary transfer roller (9) and remains on the intermediate transfer belt (7) is collected by the transfer belt cleaning means (11).

  The operation of the intermediate transfer belt (7) in the color image forming apparatus of FIG. 1 will be described in detail. The intermediate transfer belt (7) is moved endlessly in the direction of the arrow (counterclockwise direction) in the drawing while being stretched by a plurality of stretching rollers (21), (22), (23). Specifically, the plurality of stretching rollers (21), (22), and (23) are a driven roller, a driving roller, and a tension roller. The primary transfer roller (8) is a roller in which a metal core is covered with an elastic body such as sponge, and is pressed toward the photosensitive drum (2) to sandwich the intermediate transfer belt (7). It is out. Then, primary transfer nips for yellow, cyan, magenta, and black are sequentially formed along the belt moving direction by the photosensitive drum (2) and the intermediate transfer belt (7).

A primary transfer bias voltage that is constant current controlled by a transfer bias power source (not shown) is applied to the core of the primary transfer roller (8). As a result, transfer charge is applied to the back surface of the intermediate transfer belt (7) via the primary transfer roller (8), and transfer is performed between the intermediate transfer belt (7) and the photosensitive drum (2) in each primary transfer nip. An electric field is formed. In this color image forming apparatus, the primary transfer roller (8) is used as means for applying the transfer charge from the back surface of the intermediate transfer belt (7). It does not matter. Also, a transfer charger or the like may be used.
The yellow, cyan, magenta, and black toner images formed on the photosensitive drums (2) of the respective colors are transferred onto the intermediate transfer belt (7) in a primary transfer nip of the respective colors. As a result, a toner image with four colors superimposed is formed on the intermediate transfer belt (7).

  The secondary transfer roller (9) is in contact with the secondary transfer nip portion back roller on the intermediate transfer belt (7) from the belt surface side, thereby forming a secondary transfer nip portion. . A secondary transfer bias is applied to the secondary transfer roller (9) by a voltage applying means including a power source and wiring (not shown). As a result, a secondary transfer electric field is formed between the secondary transfer roller (9) and the grounded secondary transfer nip back roller (24). The four-color superimposed toner image formed on the intermediate transfer belt (7) enters the secondary transfer nip portion with the endless movement of the belt. When the toner image formed on the photosensitive drum (2) is transferred to the intermediate transfer belt (7), the photosensitive drum (2) and the intermediate transfer belt (7) are preferably in pressure contact. The pressure contact force at this time is preferably in the range of 10 to 60 N / m.

[Semiconductive member for electrophotography]
Next, in the present embodiment, an electrophotographic semiconductive member used in the image forming apparatus will be described by taking the intermediate transfer belt (7) as an example.
In this embodiment, polyethylene, polypropylene, polycarbonate, etc. are used as the thermoplastic resin material used for the electroconductive semiconductive member from the viewpoint of excellent chemical resistance, stain resistance, molding processability, and the like. It is done. Furthermore, in consideration of heat resistance, abrasion resistance, and non-adhesiveness required for the intermediate transfer belt, a polyvinylidene fluoride resin represented by a vinylidene fluoride homopolymer (PVDF) is preferable.

  For adjusting the resistance of the electroconductive semiconductive member, conductive carbon black, such as ketjen black or acetylene black, is used as a conductive resin composition by dispersing it in a predetermined resin. Besides, carbon for rubber such as SAF, ISAF, HAF, FEF, GPF, SRF, FT, MT, carbon for color (ink) subjected to oxidation treatment, pyrolytic carbon, natural graphite, artificial graphite, antimony dope Metals and metal oxides such as tin oxide, titanium oxide, zinc oxide, nickel, copper, silver, germanium, conductive polymers such as polyaniline, polypyrrole, polyacetylene, carbon whisker, graphite whisker, titanium carbide whisker, conductive titanic acid Conductive whiskers such as potassium whisker, conductive barium titanate whisker, conductive titanium oxide whisker, and conductive zinc oxide whisker are within the range (less than 50%) without impairing the achievement of the object of the present invention. You may use together. The resin is preferably polycrea, polyurethane, polythiocrea, polythiourethane, or polysulfonamide from the viewpoint of affinity with carbon black.

  By blending the conductive resin composition and the thermoplastic resin material, a sea-island structure is formed in which the conductive resin composition is discontinuously present in the thermoplastic resin matrix. The resistivity of the electrophotographic semiconductive member can be controlled by the blend ratio of the conductive resin composition and the thermoplastic resin material at this time. The conductive resin composition is desirably blended at a ratio of 1 to 45 parts by weight with respect to 100 parts by weight of the thermoplastic resin.

Regarding the resistivity, it is important how to set the values of volume resistivity and surface resistivity. Particularly when used as an intermediate transfer belt, the volume resistivity is in the range of 10 ⁵ to 10 ¹⁰ (Ω · cm), more preferably in the range of 10 ⁶ to 10 ⁸ (Ω · cm), and the surface resistivity is 10 ⁶ to 10. It is preferably in the range of 10 ¹⁰ (Ω / □). Further, it is preferable that the relationship of volume resistivity ≦ surface resistivity is satisfied.
When the volume resistivity and the surface resistivity are lower than the lower limit values, the electrostatic adhesion force with the toner is increased and the secondary transfer efficiency is lowered. On the other hand, if the upper limit is exceeded, the charge induced on the belt by the applied transfer bias is not neutralized and affects image quality such as image memory. Further, when the relationship of volume resistivity> surface resistivity is satisfied, the image edge appears blurred and a sharp image quality cannot be obtained.

  In general, a semiconductive member obtained by adding and dispersing a conductive material in a thermoplastic resin has a disadvantage that the resistivity changes according to the magnitude of a bias to be applied. In particular, when used as an intermediate transfer belt, if the resistivity of the belt material is highly dependent on the applied bias, the image quality such as fine lines and solid image portions will be adversely affected. In order to suppress this change in resistivity, it is effective to uniformly disperse the conductive material in the thermoplastic resin.

  Therefore, when the volume resistivity when the bias of 10V or 500V is applied to the semiconductivity is ρv10 and ρV500, the relationship thereof falls within the range of 0 ≦ Log (ρv10) −Log (ρv500) ≦ 1. Thus, it is preferable to adjust the electrical characteristics of the semiconductive member.

  The electrical characteristics can be adjusted, for example, by setting the resin composition to 5 to 45% by weight with respect to the thermoplastic resin.

  EXAMPLES Hereinafter, the present invention will be described more specifically based on examples. However, the present invention is not limited by these examples, and these examples are appropriately modified without departing from the gist of the present invention. Are also within the scope of the present invention.

[Measuring method]
The measurement methods and measurement conditions for each evaluation item are described below.
[(1) Volume resistivity]
Based on JIS: K6911-2006 “General Thermosetting Plastics Test Method”, volume resistivity by the ring electrode method was measured. The volume resistivity ρv is a volume resistivity measuring device manufactured by Mitsubishi Chemical Co., Ltd., under the trade name Hiresta UP. The measurement condition is a ring-shaped probe (Mitsubishi Chemical Corporation, trade name: URS probe; inner electrode diameter 5 .9 mm, outer electrode inner diameter 11.0 mm, outer electrode outer diameter 17.8 mm) and holding the sample with a load of about 30 N between the measurement stage (Mitsubishi Chemical Corporation, product name register table FL) The voltage of 100 V was applied between the inner electrode of the probe and the measurement stage for 10 seconds.
Conductive adhesive sheet (made by Kokugo Co., Ltd., trade name REP-2, thickness 1 mm, volume resistivity 0.87 Ωcm) on the inner electrode of the probe and the surface of the measurement stage is used. A product of Oken Shoji Co., Ltd., product name T-9181, thickness 0.13 mm). 21 points arbitrarily selected per A4 size of the sample to be measured were measured, and the average value was obtained.

[(2) Voltage dependence]
The voltage dependence was evaluated by looking at changes in resistivity when the 10V and 500V voltages were changed. When the resistivity at 10V application and 500V application is ρv10 and ρv500, respectively.
Log (ρv10) −Log (ρv500)
The value of was calculated.
[(3) Tensile modulus]
The tensile elastic modulus (Young's modulus) was measured based on JIS: K-7161 “Plastic—Testing method of tensile properties”.

[(4) Endurance life evaluation]
It was used as an intermediate transfer belt for a laser printer Ipsio SP C310 manufactured by Ricoh. This printer was continuously printed at a printing rate of 5%. However, the printing operation was paused every 24 sheets. T6200 manufactured by Ricoh Company was used as the transfer material. The case where cracks or cracks occurred in the intermediate transfer belt until the number of printed sheets reached 90K was evaluated as x, and the case where cracks or cracks did not occur even when the number of printed sheets exceeded 90K was evaluated as o.

[(5) Image evaluation]
Double-sided printing of solid images of green, red, and blue was performed using the laser printer in various environments (10 ° C./15% Rh, 23 ° C./65% Rh, 30 ° C./80% Rh). Classic white made of recycled paper was used as the transfer material. In the obtained image, “X” indicates a noticeable spot or white spot, “△” indicates a slightly noticeable image, and “◯” indicates an inconspicuous image.

After 10 parts by weight of carbon black (Denka Black made by Denki Kagaku Kogyo) for 10 parts by weight of polyurethane resin (Nihon Milactolan P995) is preliminarily dried at 80 ° C. for 12 hours in a vacuum, a dry blend A is prepared at a predetermined ratio. did.
Further, 30 parts by weight of vinylidene fluoride homopolymer (Kureha KF # 1000) was blended with 10 parts by weight of the dry blend A.
Next, this dry blended product is put into a micro high-shear molding machine, the gap and the internal feedback screw inner diameter are set to 1 to 2 mm and 2.5 φ, respectively, heated to 240 ° C. and melted and kneaded ( Screw rotation speed: 100 rpm and 1000 rpm, kneading time: 2 minutes), and then extruded from a T-die. Subsequently, hot pressing was performed to obtain a uniform film having a thickness of 200 μm.

10 parts by weight of carbon black (Ketjen Black EC-600JD manufactured by Ketjen Black International) is added to each 10 parts by weight of polyurea resin obtained by the method described in JP-A-2002-69149 at 80 ° C. in vacuum. After pre-drying for a time, a dry blend A was prepared at a predetermined ratio.
Furthermore, a blend of 200 parts by weight of vinylidene fluoride homopolymer (Kureha KF # 1000) to 10 parts by weight of this dry blend A was charged into a micro-type high shear molding machine, and the gap and The internal feedback screw inner diameter was set to 1 to 2 mm and 2.5φ, respectively, heated and melted to 220 ° C. and kneaded (screw rotation speed: 100 rpm and 1000 rpm, kneading time: 2 minutes), then from the T-die Extruded. Subsequently, hot pressing was performed to obtain a uniform film having a thickness of 200 μm.

20 parts by weight of carbon black (Denka Black manufactured by Denki Kagaku Kogyo) with 10 parts by weight of formaldehyde-toluene-sulfonamide condensation polymer (Kegenflex MS80 manufactured by Akzo Chemie) were each preliminarily dried at 80 ° C. for 12 hours in a vacuum, A dry blend A was produced at a ratio.
Further, 10 parts by weight of this dry blend A was blended with 12.5 parts by weight of vinylidene fluoride homopolymer (Kureha KF # 1000) and put into a micro high-shear molding machine, The internal diameter of the gap and the internal feedback type screw was set to 1 to 2 mm and 2.5φ, respectively, heated and melted to 240 ° C. and kneaded (screw rotation speed: 100 rpm and 1000 rpm, kneading time: 2 minutes). Extruded from die. Subsequently, hot pressing was performed to obtain a uniform film having a thickness of 200 μm.

[Comparative Example 1]
After 10 parts by weight of carbon black (Denka Black made by Denki Kagaku Kogyo) for 10 parts by weight of polyurethane resin (Nihon Milactolan P995) was pre-dried at 80 ° C. for 12 hours in vacuum, a dry blend A was prepared at a predetermined ratio. did.
Furthermore, a blend of 400 parts by weight of vinylidene fluoride homopolymer (Kureha KF # 1000) with respect to 10 parts by weight of this dry blend A was charged into a trace type high shear molding machine, and the gap and The internal feedback type screw inner diameter was set to 1 to 2 mm and 2.5φ, respectively, heated and melted to 240 ° C. and kneaded (screw rotation speed: 100 rpm and 1000 rpm, kneading time: 2 minutes), then from the T-die Extruded. Subsequently, hot pressing was performed to obtain a uniform film having a thickness of 200 μm.

[Comparative Example 2]
10 parts by weight of polyurethane resin (P995 made by Nippon Milactolan), 5 parts by weight of carbon black (Ketjen Black EC made by Ketjen Black International) were each pre-dried at 80 ° C. for 12 hours in a vacuum, and then a dry blended product at a predetermined ratio A was produced.
Further, 10 parts by weight of this dry blend A was blended with 10 parts by weight of a vinylidene fluoride homopolymer (Kureha KF # 1000) and put into a trace type high shear molding machine, and the gap and The internal feedback type screw inner diameter was set to 1 to 2 mm and 2.5φ, respectively, heated and melted to 240 ° C. and kneaded (screw rotation speed: 100 rpm and 1000 rpm, kneading time: 2 minutes), then from the T-die Extruded. Subsequently, hot pressing was performed to obtain a uniform film having a thickness of 200 μm.
Table 1 shows the formulation list and the evaluation results.

As is clear from the above detailed and specific description, the conductive fine particles are dispersed, and —NH—CO—NH—, —NH—CS— NH—, —NH—CS—O— is dispersed in the main chain or sub chain. , —SO ₂ NH— having a linking group (α) and a thermoplastic resin are blended to form a sea-island structure in which the resin composition (α) is dispersed in a thermoplastic resin matrix. When the volume resistivity is ρv10 and ρV500 when a bias of 10 ⁵ to 10 ¹⁰ (Ω · cm), 10V or 500V is applied, 0 ≦ Log (ρv10) −Log (ρv500) ≦ The electroconductive semiconductive member of the present invention satisfying the relationship 1 is a comparative example 1 and a comparative example using a blend of a conductive resin composition in which conductive fine particles are dispersed in polyurethane and a thermoplastic resin. 2 electronic copy It can be seen that both the endurance life and the image formed are very excellent compared to the true semiconductive member.

DESCRIPTION OF SYMBOLS 1 Process cartridge unit 2 Photoconductor drum 3 Charging roller 4 Developing means 5 Photoconductor cleaning means 6 Exposure means 7 Intermediate transfer belt 8 Primary transfer roller 9 Secondary transfer roller 10 Paper 11 Transfer belt cleaning means 21, 22, 23 Stretching roller 24 Secondary transfer nip back roller

JP 2008-291098 A JP 2006-313308 A

Claims (7)

A resin composition (α) in which conductive fine particles are dispersed is blended with a thermoplastic resin to form a sea-island structure in which the resin composition (α) is dispersed in a thermoplastic resin matrix, and the volume resistivity is 10 ⁵ to 10 ¹⁰ (Ω · cm) When the volume resistivity when a bias of 10V is applied is ρv10, and the volume resistivity when a bias of 500V is applied is ρV500,
0 ≦ Log (ρv10) −Log (ρv500) ≦ 1 is satisfied,
The semiconductive member for electrophotography, wherein the resin composition (α) has one of the following linking groups in the main chain or the sub chain.

  2. The electroconductive member for electrophotography according to claim 1, wherein the thermoplastic resin is a polyvinylidene fluoride resin.   The electroconductive semiconductive member according to claim 1 or 2, wherein the conductive fine particles are carbon black.   An electrophotographic apparatus comprising the semiconductive member for electrophotography according to any one of claims 1 to 3.   The electrophotographic apparatus according to claim 4, wherein the electroconductive semiconductive member is a transfer belt provided in contact with an image carrier.   The electrophotographic semiconductive member is a transfer sheet member that is pressed against the back surface of the transfer belt at a contact portion between the image carrier and the transfer belt. The electrophotographic apparatus according to the description.   The electrophotographic apparatus according to claim 4, wherein the electrophotographic semiconductive member is a charging sheet member provided by being pressed against an image carrier.

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