JPH1184819A - Electrifying member and electrophotographic device using that - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrifying member which shows uniform electrification property with little irregular resistance and little changes for long-term use, which is nonadhesive and which causes no sticking or contamination with a photoreceptor by mixing and vulcanizing a nitrile rubber and a nonpolar polymer to prepare a conductive elastic material to constitute the electrifying member. SOLUTION: This electrifying member is used to electrify the surface of the objective body while voltage is applied on the electrifying member. The conductive elastic material which constitutes the electrifying member is produced by mixing and vulcanizing nitrile rubber and a nonpolar polymer. In this method, the polymer used for the elastic material is nitrile rubber, and for example, when NBR (acrylonitrile rubber) is used, the molecule has a cyano group which is electrically charged into negative in the polymer molecules because the cyano group has strong electron withdrawing property. Further, by blending the rubber with a nonpolar polymer, the obtd. electrifying member shows both of uniform resistance and nonadhesive property.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging member used in an electrophotographic apparatus, and more particularly, to a charging member for charging, developing, transferring, etc., which charges a surface of an object to be charged by a charging member to which a voltage is applied. The present invention relates to an electrophotographic apparatus using the same.

[0002]

2. Description of the Related Art In image forming apparatuses such as electrophotographic apparatuses (copiers, optical printers, etc.) and electrostatic recording apparatuses, means for charging a surface of an image bearing member as a member to be charged such as a photoreceptor or a dielectric. As such, a corona discharge device has been conventionally used.

A corona discharge device is effective as a means for uniformly charging a surface of a charged body such as an image carrier to a predetermined potential. However, there is a problem that a high voltage power source is required and undesired ozone is generated because corona discharge is used.

In the contact charging device, in which the charging member to which the above-described voltage is applied is brought close to or in contact with the surface of the object to be charged, and the surface of the object to be charged is charged with respect to the above-described corona discharge device, the power supply voltage is reduced. It has advantages such as low ozone generation.

[0005] Such a charging member is required to have semi-conductivity in order to prevent uniformity of the member to be charged and leakage caused by pinholes and scratches on the surface of the member to be charged such as a photoreceptor.

For example, in the case of a transfer roller used in an image forming apparatus such as a copying machine, it is a member for transferring a toner image on an image carrier such as a photoreceptor, an intermediate transfer member, a transfer drum onto a transfer paper, The transfer roller is pressed into contact with the photoreceptor or the like on which the toner image has been developed via a transfer paper serving as a transfer target, and a charge having a polarity opposite to that of the toner of the toner image is supplied. Is absorbed and transferred to
Here, the magnitude of the charge density supplied to the transfer paper greatly affects the image quality. That is, if the charge density is low, the toner adsorbing power is weakened. In particular, in the case of dry paper, “scattering” occurs, and when the charge density is high, “bleeding” occurs due to the opposite polarity charging of the toner, resulting in high quality. No image is obtained.

[0007] If the charge density is non-uniform, density unevenness occurs in solid black transferability, and spot-like transfer unevenness such as sandy ground occurs. Therefore, it is desired that the conductivity of the surface be uniform.

In response to this requirement, a conductive metal core such as a metal is coated on a particle surface with carbon black, graphite, metal oxides such as titanium oxide and tin oxide, metal powders such as Cu and Ag, and the like. A conductive rubber roller in which conductive particles such as particles that have been made conductive is dispersed is used.

However, since the rubber roller in which the conductive particles are dispersed needs to disperse a large amount of the conductive particles in order to adjust the resistance, a variation in local resistance occurs due to uneven dispersion of the conductive particles, and as a result, There has been a problem of causing charging unevenness and destruction of the photoreceptor due to partial leakage.

[0010] In addition, as conductive means other than conductive particles, L
iC10_Four , NaSCN, LiCF _Three SO_Four Etc. ion
Ion conductive rubber with resistance adjusted by adding a non-ionic electrolyte
Is used.

In this case, there is a problem that the electrolyte migrates to the surface and the resistance value changes with time, the photosensitive member is contaminated, or the resistance is changed by charging up by applying a voltage. The required characteristics other than the resistance characteristics include, in order to ensure that the charging member is in contact with the photosensitive material and to alleviate damage to the body, the photoreceptor, etc., and particularly in the case of the transfer roller, to ensure stable paper conveyance. In particular, low hardness is required. For this reason, generally, the hardness is reduced by adding a plasticizer or oil. However, in this case, there is an adverse effect that they migrate to the surface and contaminate the charged object such as a photoreceptor, and physical properties such as resistance value and hardness change with time and durability.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has a small resistance unevenness, a uniform charging property, a small fluctuation due to durability, and a non-adhesive property with a photosensitive member. An object of the present invention is to provide a charging member having no sticking property and no contamination and an electrophotographic apparatus using the same.

[0013]

The above object is achieved by the following means.

That is, the present invention relates to a charging member for charging a surface of an object to be charged with a charging member to which a voltage is applied, wherein the conductive elastic material constituting the charging member comprises nitrile rubber, liquid nitrile rubber, and a non-polar polymer. And vulcanizing the mixture. The present invention proposes a charging member characterized by being mixed and vulcanized, wherein the conductive elastic body is further mixed and vulcanized with epichlorohydrin rubber, and the conductive elastic body is made of nitrile rubber 25 to 90. % By weight, 10 to 75% by weight of the non-polar polymer, the nitrile content of the nitrile rubber is 15 to 40% by weight, the non-polar polymer is EPDM, and the surface of the charging member. Is irradiated with ultraviolet rays. The present invention also proposes an electrophotographic apparatus using the above-mentioned charging member, and includes that the above-mentioned charging member is a transfer roller.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in more detail.

The present invention is characterized in that a mixed vulcanizate of nitrile rubber, liquid nitrile rubber and a non-polar polymer is used as a conductive elastic body on a conductive substrate.

That is, a nitrile rubber such as NBR (acrylonitrile.
When (butadiene rubber) is used, it has a cyano group in the molecule, and the cyano group is electrically negatively charged in the polymer molecule due to its strong electron-withdrawing property. In this case, it is considered that a complex is formed with the hydronium ion in the intramolecular water, and therefore, it is considered that the ion moves to exhibit conductivity.

[0018] Therefore, due to the conductivity developing mechanism caused by the material polymer itself, local unevenness in the resistance value is smaller than that of a material in which the resistance value is adjusted by dispersing the conductive particles.

Furthermore, since a conductive agent having a migration property such as a surfactant or a low molecular weight electrolyte is not added, there is no fluctuation in resistance due to migration with the passage of time or durability.

However, since a highly polar polymer such as NBR has a strong adhesiveness, it sticks or adheres to the object to be charged such as a photoreceptor when left in contact for a long time, and the components of the charging member migrate to the object to be charged. In addition, there is a problem that a roller or the like is stuck and does not rotate. Accordingly, the present invention provides a charging member that achieves both uniformity of resistance value and non-adhesion by blending with a non-polar polymer.

Here, the nonpolar polymer is a polymer having no large dipole moment in the molecule and generally a polymer having a small dielectric constant. Specific examples of such a non-polar polymer include NR (IR) (isoprene rubber), BR (butadiene rubber), SBR (styrene butadiene rubber), EPDM (ethylene propylene diene terpolymer), IIR (butyl rubber) and olefin. Elastomers, SEBS-based elastomers, polystyrene-based elastomers and the like can be mentioned. In addition, by blending these polymers, resistance adjustment to the high resistance side becomes possible, and it is possible to cope with various resistance specifications of the electrophotographic apparatus. In particular, when weather resistance such as ozone resistance becomes a problem, and when aging resistance is considered, EP
The use of DM is suitable because of its high weather resistance. Particularly in the case of sulfur vulcanization, the iodine value of the EPDM used is suitably 20 or more, preferably 30 or more, from the viewpoint of co-vulcanization.
Also, JP-A-58-87572 and JP-A-1-142256.
In the use of a hydrin rubber as disclosed in JP-A No. 9-94, although good conductivity can be obtained for the same reason as described above, since its adhesiveness is large, it is used alone as disclosed in JP-A-7-164571. Even if it is blended with a polymer, sufficient anti-adhesion effect cannot be obtained, and there are adverse effects such as deterioration of electrical characteristics due to fusion of toner to the surface of the charging member due to long-term durability. However, in the case of hydrin rubber, since the double bond is not included in the bond, the material is hardly changed due to the application of a voltage. In addition, since there is a characteristic that deterioration due to oxygen, ozone, or the like is unlikely to occur, stability due to durability can be expected. Therefore, by replacing a part of the nitrile rubber with hydrin rubber, it is possible to improve the non-adhesion and the level of durability.

The nitrile content of the nitrile rubber used is preferably from 40% by weight to 15% by weight. 40
%, The polarity becomes strong, so the tackiness increases,
The compatibility with the non-polar polymer is deteriorated, and the physical properties of the mixed vulcanizate are reduced. Further, permanent deformation after long-term pressure contact is increased, and in the case of a transfer roller or the like, transferability of a transfer material is affected, resulting in poor transfer. The mixing ratio between the nitrile rubber and the non-polar polymer is preferably 25 to 90% by weight of the nitrile rubber and 10 to 75% by weight of the non-polar polymer.

If the amount of the non-polar polymer is less than 10% by weight, there is a problem that the component of the charged body is transferred by adhering or sticking to a non-charged body such as a photoreceptor, or it is fixed by a roller and does not rotate. If it exceeds 75% by weight, the insulating component increases, and the resistance becomes non-uniform, causing a problem of uneven charging, which is not preferable.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 3 is an example of a schematic sectional view showing the configuration of the transfer roller according to the present invention.

The transfer roller of this embodiment is provided with a semiconductive elastic layer 32 on a cylindrical conductive cylindrical base material 31 made of metal or the like.

In the present invention, the semiconductive elastic layer is not particularly limited as long as it can apply a transfer bias voltage to the paper and has an elasticity enough to uniformly press the paper against the paper. Volume resistance 1E + 5Ω ~ 1E + 12
It has about Ω. Further, it is preferable that the nip width with the member to be charged is sufficiently obtained to obtain uniform charging, and particularly in the case of a transfer member, low hardness is used as a countermeasure against “center missing” in which the central portion of the line drawing comes off. Liquid NBR especially for low hardness
Is valid. That is, since liquid NBR has the same molecular structure as nitrile rubber, it has good compatibility with nitrile rubber and thus has excellent non-migratory properties. Further, the hardness can be reduced without affecting the resistance value.

As the low hardness, sponge hardness (asker
In C), 20 ° to 80 ° is preferred.

As a usage form, a solid or foam may be used. The fixation to a charged body such as a photoreceptor can be improved by blending with a non-polar polymer. As a means for further improvement, surface modification can be considered. For example, blending of release particles such as silicone particles or fluororesin particles, surface treatment with a silane coupling agent or a reactive fluorine-based surfactant, or surface cleaning with a chlorine-based solvent such as dilute hydrochloric acid can be mentioned.

However, in terms of simplicity of processing and effectiveness, U
V (ultraviolet) irradiation treatment is preferred. When a softener such as oil is used, non-migratory liquid rubber is suitable. This has the effect of oxidizing the rubber surface or hardening the surface by a crosslinking reaction between diene bonds to make the surface non-adhesive. It is also preferable that there is no effect on the physical properties as compared with additives and coating treatment.

As the UV condition, the wavelength is 180 to 600 n
m is particularly effective on the short wavelength side. Irradiation intensity is 10mW
/ Cm ^{2 to} 100 mW / cm ² .

When the charging member is in the form of a roller, if the irradiation is performed while rotating the roller, UV is uniformly applied to the entire surface, and the treatment can be performed effectively in a short time.

Further, the surface of the charging member is imparted with a high releasability by this treatment, and the extra toner and paper dust which have adhered can be easily cleaned.

FIG. 1 is a cross-sectional view of a schematic configuration diagram of an electrophotographic apparatus using the charging member according to the present invention. Reference numeral 1 denotes an image carrier as a member to be charged. In this embodiment, a drum-type electrophotographic photosensitive member having a photoconductive layer 1a formed on the outer peripheral surface as a conductive base layer 1b of aluminum or the like as a basic constituent layer. It is. It is driven to rotate around the support shaft 1d clockwise in the drawing at a predetermined peripheral speed.

Reference numeral 2 denotes a charging member that contacts the surface of the photoconductor 1 to uniformly primary-charge the surface of the photoconductor to a predetermined polarity and potential, and is required to have uniform conductivity. This example is of a roller type. Hereinafter, it is referred to as a charging roller. Charging roller 2
Is composed of the central core metal 2c, the lower conductive elastic layer 2b formed on the outer periphery thereof, and the upper resistive layer 2d formed on the outer periphery thereof as described above. As a result, the photosensitive member 1 is driven to rotate with the rotational driving. It is also effective to use the material of the present invention for the resistance layer 2d and the conductive elastic layer 2b.

When a predetermined DC (DC) bias or DC + AC (DC + AC) bias is applied to the metal core 2c by the rubbing power source 3a, the peripheral surface of the rotary photoreceptor 1 is applied. It is contact-charged to a predetermined polarity / potential. The surface of the photoreceptor 1 which has been uniformly charged by the charging member 2 is then subjected to exposure of target image information (laser beam scanning exposure, slit exposure of a document image, etc.) by the exposure means 10, so that the peripheral surface thereof An electrostatic latent image corresponding to the image information is formed.

The latent image is then visualized sequentially by the developing means 11 as a toner image. This toner image is then transferred from a paper supply unit (not shown) by a transfer unit 12 to a transfer unit between the photosensitive member 1 and the transfer unit 12 at an appropriate timing synchronized with the rotation of the photosensitive member 1. It is sequentially transferred to the surface of the material 14. The transfer unit 12 of the present embodiment is a transfer roller, and the toner image on the photoconductor 1 side is transferred to the front side of the transfer 14 by performing charging of the opposite polarity to the toner from the back of the transfer material 14.

The transfer material 14 to which the toner image has been transferred is separated from the surface of the photoreceptor 1, conveyed to an image fixing means (not shown), subjected to image fixing, and output as an image formed product. Alternatively, when an image is also formed on the back surface, the image is conveyed to a re-conveying unit to the transfer unit.

The surface of the photoreceptor 1 after the image transfer is cleaned by a cleaning means 13 to remove adhered contaminants such as untransferred toner, and is repeatedly used for image formation.

The charging member 2 may be of a blade type, a block type, a rod type, a belt type, or the like, in addition to the roller type which is used as the charging device for the image end holding member 1 in the image forming apparatus of FIG. Can be configured in form.

The roller-type charging member 2 may be driven by the surface-moved member 1 to be driven, may be non-rotating, or may be in the forward direction in the surface-moving direction of the member 1. Alternatively, the motor may be positively driven to rotate at a predetermined peripheral speed in the opposite direction. In addition, as an electrophotographic apparatus, a plurality of components, such as the above-described photoconductor, developing means, and cleaning means, are integrally combined as a process cartridge. It may be configured to be detachable with respect to a printer, a laser beam printer, or the like. For example, at least one of the charging unit, the developing unit, and the cleaning unit is integrally supported together with the photoreceptor to form a cartridge, which is a process cartridge detachable from the apparatus main body, and is detachable using guide means such as rails of the image forming apparatus main body. May be adopted. At this time, the process cartridge may be provided with a charging unit and / or a developing unit.

In the case of using an electrophotographic apparatus as a copier printer, the light image exposure is performed by reflecting light or transmitted light from an original or reading the original and converting the signal into a signal. , Or by driving a liquid crystal shutter array.

When used as a facsimile printer, optical image exposure is exposure for printing received data. FIG. 2 is a block diagram showing an example of this case. The controller 21 controls the image reading unit 20 and the printer 29. The whole controller 21 is controlled by the CPU 27. Data read from the image reading unit is sent to the printer 29 through the transmission circuit 23. Predetermined image data is stored in the image memory. The printer controller 28 controls a printer 29. 24 is a telephone.

The image received from the circuit 25 (image information from a remote terminal connected via a line) is demodulated by the receiving circuit 22, and then the CPU 27 performs a composite process of the image information and sequentially stores it in the memory 26. Is done. When at least one page of the image is stored in the memory 26, the image of the page is recorded. The CPU 27 reads out one page of image information from the memory 26 and sends the combined one-page image information to the printer controller 28. When receiving the image information of one page from the CPU 27, the printer controller 28 controls the printer 29 to record the image information of the page.

The CPU 27 receives the next page during recording by the printer 29. As described above, image reception and recording are performed. The electrophotographic apparatus is configured as follows.

The photosensitive layer is provided on a conductive support. As the conductive support, those having conductivity itself, for example, metals such as aluminum, aluminum alloys, stainless steel, and nickel can be used.In addition, aluminum, aluminum alloy, indium tin oxide alloy, and the like can be used in vacuum. Plastic, glass, or the like having a layer formed by vapor deposition can be used.

An undercoat layer having a barrier function and an adhesive function can be provided between the conductive support and the photosensitive layer. The undercoat layer can be formed of casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymer nylon, etc.) polyurethane, gelatin, aluminum oxide, or the like. The thickness of the undercoat layer is 5 μm
Hereinafter, preferably, 0.5 to 3 μm is appropriate. In order for the undercoat layer to exhibit its function, it is desirable that the thickness be 1E + 7Ω · cm or more.

The photosensitive layer can be formed by applying an organic or inorganic photoconductor together with a binder resin, if necessary, or by vapor deposition.

The form of the photosensitive layer is preferably a function-separated laminated photosensitive layer of a charge generation layer and a charge transport layer.

The charge generating layer is formed by depositing a charge generating substance such as an azo pigment, a phthalocyanine pigment, or a quinone pigment, or
It can be formed by coating with an appropriate binder resin (or even without a binder).

The thickness of the charge generation layer is 0.01 μm to 30 μm.
μm, particularly preferably 0.05 μm to 2 μm.

The charge transport layer can be formed by dissolving a charge transport material such as a hydrazone compound, a styryl compound, an oxazole compound, and a triarylamine compound in a film-forming binder resin. The thickness of the charge transport layer is preferably 5 μm to 50 μm, and particularly preferably 10 μm to 30 μm. Note that a protective layer may be provided on the photosensitive layer to prevent deterioration due to ultraviolet light or the like.

Examples of the present invention will be described below. Embodiment 1 FIG. 3 is a cross-sectional view of a transfer roller of the present embodiment, wherein 32 is a semiconductive elastic layer, and 31 is a conductive cylindrical base material.

A semiconductive elastic roller is formed on a conductive core metal of 6 mm in diameter made of stainless steel, iron or iron whose surface has been subjected to nickel or nickel-chrome plating for rust prevention.

The material of the elastic body is N230S as NBR.
(Nitrile content 35%: Nippon Synthetic Rubber) 70 parts, EPDM
EPT 4070 (Iodine value 22: Mitsui Petrochemical)
30 parts, 5 parts of zinc oxide, 1 part of stearic acid, 40 parts of calcium carbonate, 20 parts of liquid NBR, 1.5 parts of sulfur, 2 parts of vulcanization accelerator DM, and 1 part of TT were used. This rubber was formed into a tube by extrusion, and then vulcanized at 160 ° C. for 30 minutes, and further subjected to secondary vulcanization at 150 ° C. for 30 minutes using an electric furnace to obtain a vulcanized product. The tube thus obtained was pressed into a core metal coated with an adhesive and polished to obtain an elastic roller having a diameter of 12 mm. The resistance value of the obtained elastic roller was measured using an apparatus shown in FIG. 4 while rotating the aluminum drum, and the resistance value was 24 in an N / N (23 ° C., 60% RH) environment.
After standing for a period of time, a DC voltage of 2 kV is applied and 3.0E + 8 to
3.2E + 8Ω (resistance unevenness = max. / Min. = 1.
07), the hardness was 65 ° ASKER C.

Evaluation was performed using the electrophotographic apparatus shown in FIG. 1 with the above roller as a transfer roller. The process speed is 100 mm / sec. The diameter of the photosensitive drum is 30m
m. The photosensitive drum is negatively charged OPC, the toner is positively charged, and the voltage applied to the transfer roller is -3k during transfer.
V, +1.5 kV during cleaning.

When a line drawing, a solid black, and a halftone image were produced using dry paper with the above rollers, the L / L (15
° C, 10% R.C. H. ) To H / H (32.5 ° C., 80%
R. H. A clear image was obtained under any of the above conditions.

When a double-sided transfer image was evaluated using dried paper in an L / L environment, a similar clear image was obtained.

Further, the durability of 200,000 sheets was continuously evaluated, but no image defect due to the fluctuation of the resistance value occurred.

Next, at 40.degree. H. In this environment, the organic photoreceptor was pressed against the organic photoreceptor at a total pressure of 1 kg and left for 2 weeks. No adverse effects such as sticking occurred.

Further, this roller is connected to an ultraviolet irradiation device (18).
40 mW / c using 5 nm and 254 nm wavelength main components)
m ² for 4 minutes at 40 ° C., 95%
R. H. In this environment, the organic photoreceptor was pressed against the organic photoreceptor with a total pressure of 1 kg and left for 30 days. No adverse effects such as sticking occurred. Next, using this photoreceptor, an image was evaluated under an N / N environment, and a good image was obtained without any trace of contact. Example 2 The material of the elastic body was DN201 (Nitrile content 3) as NBR.
3.5%: Nippon Zeon) 70 parts, BR-01 as BR
(Japan Synthetic Rubber) A roller was obtained in the same manner as in Example 1 except that 30 parts were used. When the resistance value of the obtained elastic roller was measured while rotating it using an aluminum drum, the resistance value was measured at a DC voltage of 2 kV after standing for 24 hours in an N / N environment.
By application, 3.1E + 8 to 3.3E + 8Ω (resistance unevenness = m
ax. / Min. = 1.06), hardness is 67 ° ASKE
RC.

When the same evaluation as in Example 1 was performed using this roller, similar results were obtained. Example 3 The material of the elastic body was N240S (nitrile component 2) as NBR.
6%: Japan Synthetic Rubber) 40 parts, EP35 as EPDM
(Iodine value 26: Japan Synthetic Rubber) A roller was obtained in the same manner as in Example 1 except that the amount was 60 parts.

The resistance value of the obtained elastic roller was measured using an apparatus shown in FIG. 4 while rotating the aluminum drum. The resistance value was measured by applying a DC voltage of 2 kV after leaving the device under an N / N environment for 24 hours. 8.8E + 8 to 9.5E + 8Ω (resistance unevenness = max. / Min. = 1.08), hardness is 66 °
ASKER C.

When the same evaluation as in Example 1 was performed using this roller, similar results were obtained. Example 4 The material of the elastic body was N250S (nitrile content 2) as NBR.
0%: Japan synthetic rubber) 40 parts, hydrogenated NBR as 203
0 L (nitrile content 36.2%: Zeon Corporation) 30 parts, B
A roller was obtained in the same manner as in Example 1 except that 30 parts of BR-01 (Japanese synthetic rubber) was used as R. When the resistance value of the obtained elastic roller was measured while rotating the aluminum drum using the apparatus shown in FIG. 4, the resistance value was measured by applying a DC voltage of 2 kV after standing for 24 hours in an N / N environment. 0E
+8 to 6.4E + 8Ω (resistance unevenness = max. / Min.
= 1.07) and the hardness was 64 ° ASKER C.

When the same evaluation as in Example 1 was performed using this roller, similar results were obtained. Example 5 The material of the elastic body was N220S (Nitrile content 2) as NBR.
0%: Nippon Synthetic Rubber) 70 parts, 1502 as SBR
(Nippon Zeon) A roller was obtained in the same manner as in Example 1 except that 30 parts were used. When the resistance value of the obtained elastic roller was measured while rotating the aluminum drum using the apparatus shown in FIG. 4, the resistance value was measured by applying a DC voltage of 2 kV after standing for 24 hours in an N / N environment. 8E + 8-3E + 8Ω
(Resistance unevenness = max. / Min. = 1.07), and hardness was 70 ° ASKER C.

When the same evaluation as in Example 1 was performed using this roller, similar results were obtained. Example 6 The material of the elastic body was N230S (Nitrile content 2) as NBR.
6%: Japan Synthetic Rubber) 50 parts, EPT4 as EPDM
A roller was obtained in the same manner as in Example 1 except that 070 (iodine value: 22: Mitsui Petrochemical) was changed to 10 parts.

When the resistance value of the obtained elastic roller was measured while rotating the aluminum drum using the apparatus shown in FIG. 4, the resistance value was measured by applying a DC voltage of 2 kV after standing for 24 hours in an N / N environment. 3.8E + 8 to 4.1E + 8Ω (resistance unevenness = max. / Min. = 1.08), hardness is 68 °
ASKER C.

When the same evaluation as in Example 1 was performed using this roller, similar results were obtained. Example 7 The material of the elastic body was N240S (nitrile content 2) as NBR.
6%: Japan Synthetic Rubber) 50 parts, EPT4 as EPDM
Example 1 except that 070 (iodine value 22: Mitsui Petrochemical) 30 parts, and epichromer H (epichlorohydrin 100%: Daiso) 20 parts as a hydrin rubber.
A roller was obtained in the same manner as described above.

When the resistance value of the obtained elastic roller was measured while rotating the aluminum drum using the apparatus shown in FIG. 4, the resistance value was measured by applying a DC voltage of 2 kV after standing for 24 hours in an N / N environment. 2.6E + 8 to 2.8E + 8Ω (resistance unevenness = max. / Min. = 1.08), hardness is 64 °
ASKER C.

Using this roller, the same evaluation as in Example 1 was obtained, and the same result was obtained.
Since the change in resistance before and after the endurance of the 10,000 sheets was very small, when the endurance of the 100,000 sheets was further performed, a good image similar to the initial image was obtained. Comparative Example 1 The material of the elastic body was EPDM4070 (Mitsui Petrochemical) 10
0 parts, carbon black (HAF) 70 parts, zinc oxide 5
Parts, stearic acid 1 part, paraffin oil 55 parts, calcium carbonate 40 parts, sulfur 1 part, vulcanization accelerator M2 parts, BZ
A roller was produced in the same manner as in Example 1 except that 1 part and 1 part of TT were used.

The resistance value of the above roller was measured while rotating the aluminum drum using the apparatus shown in FIG. 4. The resistance value was measured at a DC voltage of 2 kV after standing for 24 hours in an N / N environment.
When applied, 1.2E + 8 to 2.6E + 8Ω (resistance unevenness = m
ax. / Min. = 2.2), hardness is 75 ° ASKER
C.

As in the case of the first embodiment, the evaluation results of durability and the like were the same as those of the first embodiment.

When a line drawing, a solid black, and a halftone image were produced by using the dry paper with the above rollers, an image in which characters were partially blurred in an L / L environment was obtained. Further, when the image of the double-sided transfer was evaluated using dry paper under the L / L environment, a sandy image was obtained on the second side. Comparative Example 2 The material of the elastic body was 50 parts of Epichromer H (Daiso) as epichlorohydrin rubber, 50 parts of BR-01 (Japanese synthetic rubber) as BR, 5 parts of zinc oxide, and 1 stearic acid.
Parts, 30 parts of calcium carbonate, 20 parts of liquid NBR, MgO
A roller was produced in the same manner as in Example 1 except that 5 parts and 1 part of ethylenethiourea were used.

When the resistance value of the obtained roller was measured while rotating the aluminum drum using the apparatus shown in FIG. 4, the resistance value was measured by applying a DC voltage of 2 kV after leaving the device under an N / N environment for 24 hours. 0.0E + 8 to 3.2 + 8Ω (resistance unevenness = max. / Min. = 1.07), hardness is 68 ° AS
It was KERC.

Using the above-mentioned roller, image evaluation and durability evaluation were performed in the same manner as in Example 1, and the same results as in Example 1 were obtained.

Next, at 40.degree. H. When the organic photoreceptor was pressed against the organic photoreceptor under a total pressure of 1 kg and left for 2 weeks under this environment, it was fixed.

Further, this roller was treated at 40 mW / cm ² for 4 minutes using an ultraviolet irradiation device, and the roller obtained was treated at 40% ° C. and 95% R.C. H. When the organic photoreceptor was pressed against the organic photoreceptor under a total pressure of 1 kg and allowed to stand for 30 days, sticking occurred. Next, when the solid black image was evaluated using this photoreceptor under an N / N environment, the contact mark was white. Comparative Example 3 70 parts of N215SL (48% nitrile content: Japan Synthetic Rubber) as NBR and EPT as EPDM
A roller was produced in the same manner as in Example 1, except that 4070 (iodine value: 22: Mitsui Petrochemical) was used in an amount of 30 parts.

The resistance value of the obtained roller was measured using an apparatus shown in FIG. 4 while rotating the aluminum drum. The resistance value was 1 hour after being left for 24 hours in an N / N environment and applying a DC voltage of 2 kV. 0.2E + 8 to 1.6E + 8Ω (resistance unevenness = max. / Min. = 1.3), hardness: 70 ° AS
It was KERC.

Using the above-mentioned rollers, image evaluation, durability evaluation and pressure contact evaluation were performed in the same manner as in Example 1, and similar results were obtained.

Further, the roller obtained by treating this roller at 40 mW / cm ² for 4 minutes using an ultraviolet irradiation device was heated to 40 ° C. and 95% R.C. H. Photoreceptor and total pressure 1
When pressed with a kg load and left for 30 days, no adverse effects such as sticking occurred, but using this photoconductor, N / N
When the solid black image was evaluated under the environment, the contact trace was white. Comparative Example 4 Instead of liquid NBR, a polyester plasticizer (W-
A roller was obtained in the same manner as in Example 1 except that 20 parts of 305ELS (Dainippon Ink Kogyo) was used.

When the resistance value of the obtained elastic roller was measured while rotating the aluminum drum using the apparatus shown in FIG. 4, the resistance value was measured by applying a DC voltage of 2 kV after standing for 24 hours in an N / N environment. 5.3E + 8 to 5.8E + 8Ω (resistance unevenness = max. / Min. = 1.09), hardness is 65 °
ASKER C.

Using the above-mentioned rollers, image evaluation and durability evaluation were performed in the same manner as in Example 1, and similar results were obtained.

Next, at 40.degree. H. In this environment, the plasticizer was pressed against the organic photoreceptor under a total pressure of 1 kg and allowed to stand for 2 weeks, but there was no sticking, but the plasticizer had migrated onto the photoreceptor.

Further, the roller obtained by treating this roller at 40 mW / cm ² for 4 minutes using an ultraviolet irradiation device was heated to 40 ° C. and 95% R.C. H. Photoreceptor and total pressure 1
When pressed under a kg load and left for 30 days, no adverse effects such as sticking occurred, but the plasticizer had migrated onto the photoreceptor. Next, when this solid was used to evaluate a solid black image in an N / N environment, the contact trace was white, and the toner was fixed to the roller contact trace on the drum.

[0085]

As described above, by contacting the charging member to which a voltage is applied with the member to be charged, the charging member for charging the surface of the member to be charged is treated with the nitrile rubber and the elastic member constituting the charging member. By using a mixed vulcanizate with liquid nitrile rubber and non-polar polymer, low hardness,
Since a uniform chargeability with a small resistance unevenness can be obtained and a non-adhesive state can be obtained, it is possible to provide a charging member and an electrophotographic apparatus free from sticking and contamination after long-term pressure contact with a member to be charged such as a photoreceptor. is there. Since there is little fluctuation due to durability and non-adhesion, it is possible to provide a charging member that does not stick to a non-charged member such as a photoreceptor after long-term pressure contact, and an electrophotographic apparatus using the same.

Further, by mixing and vulcanizing epichlorohydrin rubber, it is possible to provide a charging member with less fluctuation due to durability.

Further, the surface of the charging member is irradiated with ultraviolet rays (UV).
By irradiating, the non-adhesiveness to the non-charging member is further improved, and the transfer of the internal components of the charging member to the surface of the member to be charged can be suppressed, so that after long-term contact under high temperature and high humidity, Thus, a good image can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a general electrophotographic apparatus using a charging member according to the present invention.

FIG. 2 is a block diagram of a facsimile using the electrophotographic apparatus using the charging member according to the present invention as a printer.

FIG. 3 is a schematic sectional view illustrating an example of a transfer roller according to the present invention.

FIG. 4 is a diagram showing a configuration of a device for measuring a resistance value of a semiconductive elastic roller.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrophotographic photoreceptor 1 a conductive support 1 b photosensitive layer 2 charging roller 2 c cored bar 2 b conductive layer (lower resistance layer) 2 d resistance layer (upper resistance layer) 3 power supply 10 photosensitive means 11 developing means 12 transfer roller 13 cleaning Means 14 Transfer material 31 Conductive cylindrical base material 32 Semi-conductive elastic layer 41 Semi-conductive elastic roller 42 Aluminum drum 43 Conductive metal core

Continued on the front page (51) Int.Cl. ⁶ Identification code FI (C08L 9/02 21:00) (C08L 9/02 23:16) B29K 9:00 105: 24

Claims (8)

[Claims] 1. A charging member for charging a surface of an object to be charged with a charging member to which a voltage is applied, wherein a conductive elastic body constituting the charging member is a mixture of vulcanized nitrile rubber, liquid nitrile rubber, and a nonpolar polymer. A charging member comprising: a charging member; 2. The charging member according to claim 1, wherein epichlorohydrin rubber is further mixed and vulcanized to the conductive elastic body. 3. The method according to claim 1, wherein the conductive elastic body is a nitrile rubber.
3. The charging member according to claim 1, wherein the amount of the non-polar polymer is 10 to 75% by weight. 3. The charging member according to claim 1, wherein a liquid nitrile rubber is used as the mixed vulcanized product. 4. The charging member according to claim 1, wherein said nitrile rubber has a nitrile content of 15 to 40% by weight. 5. The charging member according to claim 1, wherein the non-polar polymer is EPDM. 6. The charging member according to claim 1, wherein the surface of the charging member is irradiated with ultraviolet rays. 7. An electrophotographic apparatus using the charging member according to any one of claims 1 to 6. 8. The electrophotographic apparatus according to claim 7, wherein said charging member is a transfer roller.