JP2003140419A - Conductive member and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive member which can eliminate the problems of initial fogging, durable fogging and OPC adhesiveness and ensures the good development operation, transfer operation, cleaning operation, etc., even under severe conditions and makes it possible to stably obtain good images. SOLUTION: The conductive member is a conductive member used for an electrophotographic device and is furnished with an elastic layer and at least one resin layer formed on this elastic layer, in which the outermost resin layer forming the member surface is formed of a resin material containing >=50 wt.% polyamide resin and <=50 wt.% fluororesin and/or fluorine compound component. The above conductive member is <=50 V in the maximum value of the surface potential after 0.3 seconds when the surface of the outermost resin layer is electrified by applying a voltage of 8 kV to a corona discharger arranged apart a spacing of 1 mm from the surface of the outermost resin layer in a state not to contain conducting agents at all and is <=5 V in the surface potential after 10 seconds.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive member used in a developing device, a transfer device, a cleaning device or the like used in an electrophotographic device or an electrostatic recording process, and a developing device, a transfer device or a developing device using the conductive member. The present invention relates to an electrophotographic apparatus equipped with a cleaning device.

[0002]

2. Description of the Related Art Conventionally, in electrophotographic devices such as copying machines and printers, the surface of a photoconductor is first uniformly charged, and an image is projected from the optical system onto the photoconductor to charge the exposed portion. A latent image is formed by erasing the image, and then a toner image is attached, the toner image is transferred to a paper, and cleaning is performed after the transfer to perform copying.

In these processes, first, regarding development, a non-magnetic one-component developer is supplied to a photosensitive drum or the like holding a latent image, and the developer is attached to the latent image on the photosensitive drum to form a latent image. A pressure developing method is known as a developing method for visualization (U.S. Pat. Nos. 3,152,2012 and 37311).
No. 46, etc.), this method does not require a magnetic material, so that the apparatus can be simplified and downsized, and the toner can be colored easily.

In this pressure developing method, as shown in FIG. 2, a developing roller 6 carrying a toner (non-magnetic one-component developer) holds a latent image on a photosensitive drum such as an electrostatic latent image. The development is performed by bringing the toner into contact with the body 5 and adhering the toner to the latent image of the latent image holding body 5. Therefore, the developing roller 6 is in close contact with the latent image holding body 5 such as a photosensitive drum. Must be securely held and rotated, and must be formed of an elastic body having conductivity.

Further, in a transfer device for transferring a toner image developed and visualized with toner from a latent image carrier onto a transfer sheet, conventionally, the transfer sheet is charged by using a corona charger to transfer the toner image onto the transfer sheet. Transfer is generally used, but corona discharge has problems such as generation of ozone and the need for a high-voltage power supply. As a transfer device that solves this problem, there is known a transfer device that charges a transfer paper 8 by using a bias roller (transfer roller) 9 made of conductive rubber, as shown in FIG. In this method, in order to obtain high transfer efficiency and a transferred image without unevenness, a constant nip width is set between the photosensitive drum 5 and the roller,
The pressure between the drums should be low and fairly soft conductive rubber must be used. In the apparatus of FIG. 2, the toner image transferred onto the transfer paper 8 is fixed by the fixing device 13.
Is heated and fixed on the transfer paper 8.

Further, the toner left on the photosensitive drum after the transfer of the toner image is removed by a cleaning device. As the cleaning device, the edge of a blade formed of urethane rubber or the like on a conventional photosensitive member is pressed. Generally, the toner is scraped off. However, when such a blade is used, the frictional force with the photoconductor is large, the driving force is large, the photosensitive drum is easily scratched by the edge, and when the rubber plate is scratched, cleaning cannot be performed in some cases. As one of the solutions to such a problem, as shown in FIG. 2, a cleaning roller 11 capable of applying a voltage is used.
There is proposed a cleanerless method in which a cleaning device 12 is configured by using a cleaning roller 11, and the cleaning roller 11 directly removes residual toner from the surface of the photosensitive drum 5 or forcibly charges the toner and collects the toner by a developing roller or the like. ing. This cleaning roller is also required to have the same characteristics as the above-mentioned transfer roller and the like.

Conventionally, as conductive members such as the developing roller, the transfer roller, and the cleaning roller, for example, on the surface of an elastic layer such as rubber or urethane foam, to secure the smoothness of the surface, adjust the resistance, and improve the charging property, Acrylic, urethane, nylon, polyethylene, epoxy, polyester, polyether, polystyrene, phenol, AB
It is known that a resin solution is formed by applying a resin solution of S, polyamide, urethane-modified acrylic resin or the like by a dipping method or a spray method.

[0008]

However, the above-mentioned conventional conductive member has the following problems. [Initial fog / durable fog] In response to the recent demands for higher image quality, lower cost (lower voltage, smaller members, etc.), higher speed, and higher durability in the electrophotographic field, a developing roller,
A conductive member such as a transfer roller or a cleaning roller may cause problems such as: initial image defect (initial fog), and durable image defect (durability fog) caused by stacking prints. However, the root cause of this has not been clarified, and there are currently no clear measures that can be fully satisfied.

[OPC contact] The conductive members such as the developing roller, the transfer roller, and the cleaning roller are the photosensitive member (OP).
Since it is in contact with C) for a long period of time, adhesion (adhesion) may occur between the photoconductor and the surface of these members, resulting in peeling of the coating film and contamination of the photoconductor. In particular, in recent years, there has been a strong demand for the development of a conductive member, particularly a resin layer on the surface of the member, which is excellent in releasability without coming into close contact with the photoconductor even under severe conditions such as temperature / humidity, etc., in response to demands for multi-environment.

The present invention has been made in view of the above circumstances, and is capable of solving the problems of [initial fog / durability fog] and [OPC adhesion], and good development operation and transfer even under severe conditions. An object of the present invention is to provide a conductive member capable of reliably performing an operation, a cleaning operation, etc. and stably obtaining a good image, and an electrophotographic apparatus using the conductive member.

[0011]

MEANS FOR SOLVING THE PROBLEMS AND BEST MODE FOR CARRYING OUT THE INVENTION As a result of intensive studies to achieve the above object, the present inventor has formed at least one resin layer on an elastic layer, When obtaining a conductive member such as a transfer roller or a cleaning roller, the outermost resin layer forming the surface of the member is set to 5
When the outermost resin layer is made of a resin material containing 0% by weight or more of a polyamide resin and 50% by weight or less of a fluorine resin component and / or a fluorine compound component, and the outermost resin layer contains no conductive agent, 1m with the outer resin layer surface
When a voltage of 8 kV is applied to a corona discharger arranged at intervals of m to generate a corona discharge and the outermost resin layer surface is charged, the maximum value of the surface potential after 0.3 seconds is 50 V or less. By setting the surface potential after 5 seconds to be 5 V or less, it is possible to solve the problems of [initial fog / durability fog] and [OPC adhesion] as described below. It has been found that a conductive member such as a developing roller, a transfer roller, or a cleaning roller can be obtained which can perform a good developing operation, a transferring operation or a cleaning operation even under the conditions and can stably obtain a good image. .

[Initial fog / durable fog] According to the study by the present inventors, the above-mentioned [initial fog / durable fog] is
Mainly depends on the resin layer of the conductive member, particularly the outermost resin layer, and among them, "initial fog", in the state where the outermost resin layer of the conductive member does not contain any conductive agent, and the surface of the outermost resin layer When a voltage of 8 kV was applied to a corona discharger arranged at an interval of 1 mm to generate a corona discharge and the outermost resin layer surface was charged, the maximum value of the surface potential after 0.3 seconds was 50 V. When the conductive member is capable of retaining the “surface charging potential characteristic”, which is the following, and the surface potential after 10 seconds is 5 V or less, it is possible to extremely effectively prevent the occurrence of the “initial fog”. As for "durability fog", it has been found that if "initial fog" does not occur, it is much more advantageous than "initial fog" even if there is some deterioration. On the other hand, in order to suppress "durability fog", it has been found that, in addition to the "surface charging potential characteristic", the toner adhesion and frictional property of the outermost resin layer of the conductive member are important. In other words, if toner adheres to conductive members such as a developing roller, a transfer roller, and a cleaning roller, or if the toner has difficulty in removing toner, fogging occurs due to toner damage to the conductive members such as toner filming and toner fusion. Will be done. If the outermost resin layer has a high frictional property, the shear stress between the photoconductor and the conductive member becomes excessive, causing fog due to damage such as slack, wrinkles, and perforations. Therefore, as a result of further study on this point, when the conductive member is made of 100% cellulose, 30 g / m ² , and 70 mesh cloth and a pressure of 100 gf is applied to the cloth, the friction coefficient to the cloth is 0.5 or less. It has been found that the occurrence of this "durable fog" can be suppressed very effectively when it has friction characteristics.

Here, the reason for evaluating the surface potential characteristics when corona discharge is used as a measure against "fogging" is as follows. That is, "fogging" is a so-called image defect, which is caused by mechanical defects, environmental defects, electrical defects, and defects somewhere such as the developing roller, the transfer roller, and the cleaning roller. The most frequent cause of this is common to all rollers, and electrical failure due to surface residual charge is the most common cause. That is, all of these rollers play their role by applying a voltage, but when no voltage is applied, the presence of residual charge on the surface of the rollers causes electrical non-uniformity when a voltage is applied during operation. Will occur. This electrical non-uniformity appears as a fatal image defect for these conductive rollers, and causes fog such as so-called "white spots", "black spots", "horizontal stripes", and "vertical stripes". Therefore, when this voltage is not applied, the surface residual charge must be eliminated as much as possible. Therefore, the performance of preventing the occurrence of the above "fog" can be evaluated by the surface charge attenuation characteristic accompanying the surface potential measurement by corona discharge. In the present invention, the surface charge attenuation characteristic is evaluated and adjusted. .

Further, when the charging potential characteristic is evaluated, the evaluation is carried out in the state where the outermost resin layer contains no conductive agent at all. That is, in a conductive roller such as a developing roller, a transfer roller, or a cleaning roller, it is usual that the resistance increases from the shaft toward the outer layer. There is a reason. Therefore, it can be said that the surface charge permeability of the roller depends substantially only on the surface layer. And, in this surface layer, it may contain a conductive agent, in which case the conductive agent may help the surface charge decay to some extent, but when the conductive agent is a filler, the fillers are microscopically different from each other. Since there is almost no contact, the filler cannot completely prevent the charge from staying in the surface layer resin, and in the end, if the charge permeability of the resin alone is not excellent, there is no residual charge. It cannot be. Further, when the conductive agent is an ionic conductive agent, a concentration gradient of the ionic conductive agent is usually generated in the resin, and a portion in which the ionic conductive agent is hardly present is generated. The charge permeability of a single substance becomes important. Therefore, the charge permeability of the resin alone in the outermost resin layer is the most important parameter, and in the evaluation of surface potential characteristics, it is appropriate to perform the evaluation in the state where the outermost resin layer does not contain any conductive agent. It becomes.

Further, the reason for evaluating the charging potential 10 seconds after the charging by corona discharge is as follows. That is, a large potential of 8 kV (which is considered to be a slightly lower voltage in a conductive roller) is applied to the surface of the conductive roller by corona discharge, but such a large voltage is not normally applied in an actual machine. But,
Due to problems such as measurement accuracy, reproducibility, and measurement method, such a large voltage is applied. Therefore, considering this point,
This is because the surface potential is evaluated when an interval of 10 seconds is given to allow the charges to escape, and this evaluation method is appropriate based on empirical rules.

[OPC adhesion] The problem of [OPC adhesion] can be solved by good releasability as described above, but according to the study of the present inventors, the conductive member is made of cellulose. The releasability of the surface of the member is 100%, if the member has friction characteristics such that the coefficient of friction with respect to the cloth of 30 g / m ² , 70 mesh is 100 when the load of 100 gf is applied under pressure. It has been found that the above can be sufficiently secured, and the problem of [OPC adhesion] can be sufficiently solved.

A developing roller, a transfer roller, a resin material containing 50% by weight or more of a polyamide resin and 50% by weight or less of a fluororesin component and / or a fluorine compound.
By forming the outermost resin layer of the conductive member such as the cleaning roller, it is possible to obtain the outermost resin layer having the above-mentioned "surface electrification potential characteristic" which can solve the problem of "initial fog / durability fog". It is possible to easily form the outermost resin layer having the above-mentioned "friction characteristics" which can solve the problem of "durability fog" more reliably and the problem of the above [OPC adhesion], and under severe conditions The present invention has been completed by finding that a conductive member capable of reliably performing a favorable developing operation, transferring operation, and cleaning operation and obtaining a stable image can be obtained.

Therefore, according to the present invention, a conductive member used in an electrophotographic apparatus comprises an elastic layer and at least one resin layer formed on the elastic layer, and constitutes the surface of the member. The outermost resin layer is a conductive member formed of a resin material containing 50% by weight or more of a polyamide resin and 50% by weight or less of a fluororesin component and / or a fluorine compound component, and the outermost resin layer is In a state where no conductive agent is contained, a voltage of 8 kV is applied to a corona discharger arranged at a distance of 1 mm from the surface of the outermost resin layer to generate corona discharge and charge the surface of the outermost resin layer. In this case, the maximum value of the surface potential after 0.3 seconds is 50 V or less, and the surface potential after 10 seconds is 5 V or less, and the conductive member is a developing roller or the like. of Image member, a transfer member such as a transfer roller, or to provide an electrophotographic apparatus characterized by using as a cleaning member of the cleaning roller or the like.

The present invention will be described in more detail below.
As described above, the conductive member of the present invention has the outermost resin layer forming the surface of the member formed of a resin material containing a polyamide resin and a fluororesin component and / or a fluorine compound component.

The polyamide resin used as the resin material for forming the outermost resin layer may be any one that can be formed into a film on the elastic layer serving as the base of the electrically conductive member, and may be an aliphatic resin formed through an amide bond. Aliphatic, aromatic-aromatic, aliphatic-
It may have any aromatic constitution, as long as it can obtain the above-mentioned charging potential characteristics by corona discharge.

Although this polyamide resin has good electric characteristics and physical properties preferable as a skin layer of a conductive member,
It also has the disadvantage of high tack and high friction.
Therefore, in the present invention, by adding and using a fluororesin and / or a fluorine compound component together, the above problems of tackiness and frictional properties are solved while maintaining good electrical characteristics.

Examples of the above-mentioned fluororesin component include polytetrafluoroethylene, polytetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene- Ethylene copolymer, polychlorotrifluoroethylene, chlorotrifluoroethylene-ethylene copolymer, tetrafluoroethylene-vinylidene fluoride copolymer, polyvinylidene fluoride, polyvinylidene fluoride copolymer, vinylidene fluoride-hexa Examples include fluoropropylene copolymers, and one or more of these can be used.

The fluororesin component and the polyamide resin may be simply blended, or may be chemically bound by a graft, a bond through a crosslinking agent such as isocyanate, or the like.

Further, as the fluorine compound component, perfluorooctylethyl methacrylate, 2,2,3,4,
4,4-hexafluorobutyl methacrylate, 2,2,3,
Examples thereof include 3-tetrafluoropropyl methacrylate, trifluoroethyl methacrylate, a fluorine-modified acrylate having a fluoroalkyl group bonded to the end of a polyol, and a fluorine-modified polyamide having a fluoroalkyl group bonded to the end of a polyamide. One or two of these may be mentioned. More than one species can be used.

Here, although not particularly limited,
The fluoroalkyl group C _n F _{2n + 1} in the fluorine compound preferably has n of 6 or more. This is because when n is 5 or less, the low surface energy peculiar to the fluoroalkyl group may not be sufficiently exhibited, and when n is 6 or more, the characteristics are rapidly exhibited, and low friction property and low adhesiveness are good. This is because it is often exhibited in.

The fluorine compound component and the polyamide resin may be simply blended, but it is particularly preferable that they are chemically bonded by a bond such as a graft or a crosslinking agent such as isocyanate. This is because when the fluorine compound has a low molecular weight, there is a possibility that contamination of the photoreceptor and a decrease in durability may occur due to bleed-out. In addition, the outermost resin layer preferably has an inclined structure in which fluorine is dense on the outside and polyamide is dense on the inside from the viewpoint of action and effect, but the fluorine compound is low in polarity, Even if it is bonded to the resin, it is more likely to be on the air side, that is, the outermost side. Therefore, even if it is bonded to the polyamide resin, there is no particular disadvantage in obtaining the inclined structure.

In the present invention, the fluororesin component and the fluorocompound component may be used in combination.

The outermost resin layer constituting the member surface of the conductive member of the present invention contains the polyamide resin and the fluororesin component and / or the fluorine compound component as the resin component as described above. In this case, the polyamide resin content is 50% by weight or more, more specifically 50 to 99.9% by weight, preferably 60 to 99% by weight, and the fluororesin component and / or the fluorine compound component is 50% by weight or less, more specifically. 0.1 to 50% by weight, preferably 1 to 40
It is defined as weight%. Here, if the polyamide resin component is less than 50% by weight, good electrical properties and mechanical properties peculiar to the polyamide resin may not be obtained, and if the amount of the fluororesin component and / or the fluorine compound component is too small, the tackiness against tack may be reduced. The potency is not so great, and when it is too large, the potency does not change so much, which may cause problems such as phase separation and deterioration of electrical properties.

Although not particularly limited, silica powder may be added and compounded in the resin material forming the outermost resin layer, which reduces the contact area, thereby improving the adhesion (non-adhesiveness). ) May be improved. Further, in this resin material, a conductive agent can be added as necessary to adjust the resistance to a desired value. In this case, the conductive agent is not particularly limited, and various electronic conductive agents and various ionic conductive agents can be used. Although an agent can be used, a conductive powder such as carbon is particularly preferably used in the present invention. The electric resistance of the outermost resin layer is not particularly limited, but is usually 10 ⁶ to 10 ¹³ Ω · cm, particularly 10 ⁷ to 10
It is preferably ¹² Ω · cm.

The method for forming the outermost resin layer on the conductive member is not particularly limited, but a coating material containing each of the above components is prepared and the coating material is applied to the conductive member by a dipping method or a spray method. The method is preferably used.

The thickness of the outermost resin layer is appropriately set according to the form of the conductive member and is not particularly limited, but is usually 50 μm or less, particularly preferably 2 to 30 μm. If it exceeds 50 μm, the outermost resin layer may be hardened and the flexibility of the outermost resin layer may be impaired.

If necessary, additives such as a cross-linking agent, a thickener, a thixotropy-imparting agent, and a structural viscosity-imparting agent can be added to the resin composition forming the outermost resin layer.

The conductive member of the present invention may be any one as long as at least the surface of the member is formed of the outermost resin layer, and its form is roll-like or plate-like depending on the application and the configuration of the electrophotographic apparatus used. It may be in any suitable form such as a block, a sphere, or a brush, and is not particularly limited, but it is usually preferable to use a roll-shaped conductive roller having the outermost resin layer on the member surface. , For example,
As shown in FIG. 1A, a conductive roller in which an elastic layer 2 is formed on the outer circumference of a shaft 1 and the outermost resin layer 3 is formed on the elastic layer 2 can be exemplified.

In this case, a metal or plastic shaft can be used as the shaft 1.
The shaft 1 may be omitted depending on the form of the member and the mechanism of the electrophotographic apparatus in which the conductive member is used.

Further, the elastic body forming the elastic layer 2 is not particularly limited as long as it is an elastic body capable of obtaining a good contact state with a mating member such as a photosensitive drum or transfer paper,
Known rubber or resin, or foams thereof (hereinafter,
"Form"). Specifically, polyurethane, silicone rubber, butadiene rubber, isoprene rubber, chloroprene rubber, styrene-butadiene rubber, ethylene-propylene rubber, polynorbornene rubber, styrene-butadiene-styrene rubber, epichlorohydrin rubber, acrylic rubber, nitrile rubber, etc. A rubber composition as a base rubber is exemplified.

By adding a conductive agent to the elastic layer 2, the conductivity can be imparted or adjusted to a predetermined resistance value. The conductive agent is not particularly limited,
Lauryl trimethyl ammonium, stearyl methyl ammonium, octadodecyl trimethyl ammonium,
Hexadecyltrimethylammonium, modified fatty acid / dimethylethylammonium perchlorate, chlorate, borofluoride, sulfate, ethosulfate salt, benzyl bromide, benzyl chloride, etc. Cationic surfactant such as quaternary ammonium salt, aliphatic sulfonate, higher alcohol sulfate ester salt, higher alcohol ethylene oxide addition sulfate ester salt, higher alcohol phosphate ester salt, higher alcohol ethylene oxide addition phosphate ester salt, etc. anionic surfactants, higher alcohol ethylene oxide, polyethylene glycol fatty acid esters, polyhydric alcohol fatty acid antistatic agent such as a nonionic antistatic agents such as _{esters, NaClO 4, LiAsF 6, LiBF} 4, NaSC
Electrolytes such as metal salts of Group 1 of the periodic table such as Li ⁺ , Na ⁺ and K ⁺ such as N, KSCN and NaCl, or salts of NH ₄ ⁺ , and conductive carbon such as Ketjen black and acetylene black , SAF, ISAF, HAF, FE
Carbon for rubber such as F, GPF, SRF, FT, MT,
Oxidized carbon for color (ink), pyrolytic carbon, natural graphite, artificial graphite, antimony-doped tin oxide, titanium oxide, zinc oxide, nickel, copper, silver, and metal oxides such as germanium, polyaniline Conductive polymers such as polypyrrole and polyacetylene. In this case, the blending amount of these conductive agents is appropriately selected according to the type of composition and the type of conductive member and is not particularly limited, but usually the volume resistivity of the elastic layer is 10 ⁴ to 10 ^4. It is adjusted to ⁹ Ω · cm, preferably 10 ⁵ to 10 ⁷ Ω · cm.

The thickness of the elastic layer 2 is appropriately set according to the type, form, size, layer structure, etc. of the member and is not particularly limited, but will be described with reference to FIG. In the case of a roll-shaped conductive member as shown in FIG. 1 (B), it is usually preferably 2 to 30 mm, particularly preferably 3 to 20 mm.

Here, the outermost resin layer 3 is formed by coating the elastic layer 2 with a coating material of a resin material made of a polyamide resin containing the fluororesin component and / or the fluorine compound component as described above. In this case, the solvent used for the paint may be water-based or solvent-based.

If necessary, an intermediate resin layer 4 may be provided between the outermost resin layer 3 and the elastic layer 2 as shown in FIG. 1 (B). In this case, the resin forming the intermediate resin layer 4 is not particularly limited, but an aqueous resin is preferably used. As the water-based resin, any type may be used as long as the solvent is water, and there are water-soluble type, emulsion type, suspension type and the like, and a resin having active hydrogen such as carboxyl group, hydroxyl group and amino group is preferably used. . More specific examples include polyester-based, acrylic-based, urethane-based, and hot water-soluble systems such as polydioxolane. Among these, acrylic resin has a much smaller dielectric constant than urethane, nylon, etc., which have been widely used as a resin for conductive members, so that the electrostatic capacity also becomes smaller, and the electrical conductivity between the conductive member and the photoconductor due to the application of alternating current is reduced. It is particularly preferably used because the attractive force and repulsive force are reduced and the generation of charging noise is suppressed. Among the acrylic resins, a soap-free emulsion type one having a glass transition temperature of −50 to 10 ° C., a content ratio of a carboxyl group and a hydroxyl group of 2 to 5% by weight, has a good crosslinking effect and a low hardness. It is preferably used because it is possible.

A conductive agent may be added to the intermediate resin layer 4 to impart or adjust conductivity. In this case, as the conductive agent, the same conductive agents as those exemplified for the elastic layer 2 can be exemplified, but it is preferable to use carbon among them, and particularly, the oxygen content is 5% or more,
In particular, 7% or more, more preferably 9% or more,
Further, the pH is preferably 5 or more, particularly 6 or more, and further preferably 7 or more. That is, the oxygen content of ordinary carbon is about 0.1 to 3%, and there is some carbon that has been subjected to an oxidation treatment, but the oxygen content of this oxidation-treated carbon slightly increases. As a result, the pH tends to shift to the acidic side, and if the carbon is acidic, the stability may decrease when added to the water-based resin. On the other hand, the above-mentioned carbon maintains neutrality or alkalinity despite having a large oxygen content, and can be stably added to the water-based resin. Further, those obtained by adding a functional group such as a carboxyl group, a hydroxyl group or a ketone group to the surface of carbon and substituting a part of hydrogen contained in these groups with an alkali metal such as sodium are preferably used. In addition, this specific oxygen content and pH
When the outermost resin layer 3 is formed of a water-based paint, the carbon having a value is also suitably used as the carbon to be added to the outermost resin layer 3 as a conductive agent.

The intermediate resin layer 4 contains appropriate additives such as a film-forming aid, a pigment dispersant, a thickener, a leveling agent, a thixotropy-imparting agent, and a structural viscosity-imparting agent within the range not departing from its purpose. Can be added in an appropriate amount if necessary.

The intermediate resin layer 4 is preferably formed by using a water-based resin as described above, but may contain a resin other than this water-based resin, and if necessary, this It is also possible to form a plurality of intermediate resin layers 4.

The method of forming the intermediate resin layer 4 is not particularly limited, and a known dipping method, spraying method, extrusion molding method or the like can be adopted. Usually, a coating in which each component is dissolved or dispersed in a solvent is used. Is preferably used to form a coating film by a dipping method.

As described above, the conductive member of the present invention has the outermost resin layer 3 formed on the elastic layer 2 via the intermediate resin layer 4 or directly. In this case, suitable resistance as a conductive member is obtained in any layer structure and application.
Volume resistance is 10 ⁵ to 10 ¹¹ Ωc to obtain a good image
m is preferable, and particularly 10 ⁶ to 10 ¹⁰ Ωcm
Is preferred.

Here, in the conductive member of the present invention, the above outermost resin layer contains no conductive agent (when the outermost resin layer is mixed with the conductive agent, the conductive agent is excluded). Except for the above-mentioned conductive member), a voltage of 8 kV is applied to a corona discharger arranged at a distance of 1 mm from the surface of the outermost resin layer to generate corona discharge, and When charged, the maximum value of the surface potential after 0.3 seconds is 50 V or less, especially 35 V or less, and the surface potential after 10 seconds is 5 V or less, especially 3.5 V.
It has a charging potential characteristic that As a result, it is possible to reliably prevent the occurrence of the above-mentioned "fog", particularly the "initial fog". Further, according to the conductive member of the present invention in which the outermost resin layer is formed, such charging potential characteristics can be easily achieved.

As a specific method for measuring the surface potential of the conductive member and evaluating the above charging potential characteristics, for example, "Charge Roller Test System CRT2000" of QEA (Quality Engineering Associates, Inc.) in the United States is used. , As shown in FIG. That is,
The conductive member (conductive roller in the figure) on which the outermost resin layer is formed is used as a subject roller 21, and both ends of a shaft 22 of the subject roller 21 are fixed to a chuck 23, and a small scorotron discharger 24 and a surface electrometer are provided. 25 and the measuring unit 20 provided side by side with a predetermined distance from each other.
It is arranged facing the surface of No. 1 with a space of 1 mm,
The measurement unit 20 is moved from one end to the other end of the subject roller 21 at a constant speed while the subject roller 21 is kept stationary, and the surface potential of the subject roller 21 is measured while applying a surface charge to the subject roller 21. At this time, the moving speed of the measuring unit 20 may be adjusted to measure the “surface potential after 0.3 seconds” and the “surface potential after 10 seconds”. In this case, since the surface potential depends on temperature and humidity, the measurement is carried out in an atmosphere of normal temperature and normal humidity (22 ° C./50% RH) as standard conditions. The corona charge applied from the scorotron discharger 24 to the subject roller 21 is a negative charge, and the applied voltage is 8 kV as described above.

The conductive member of the present invention preferably has a small friction resistance on the surface thereof, and although not particularly limited, a load of 100 gf is applied to a cloth of 100% cellulose, 30 g / m ² , 70 mesh. It is preferable that the friction coefficient with respect to the cloth when pressed against the surface is 0.5 or less, particularly 0.35 or less. This causes "fog",
In particular, it is possible to more reliably prevent the occurrence of "durable fog" and the "OPC adhesion". Further, according to the conductive member of the present invention in which the outermost resin layer is formed, such surface friction characteristics can be easily achieved.

In this case, the friction coefficient can be measured by the measuring device shown in FIG. That is, the cellulose 10 is attached to the movable stage 52 provided on the base 51.
A 0%, 30 g / m ² , 70 mesh cloth (Bencott lint-free) 15 is fixed, and the conductive member 14 of the present invention to be evaluated is placed on the cloth 15 in a state of being contacted, and 100 gf is applied by the pressing means 53. Is applied to bring the cloth 15 and the conductive member 14 into pressure contact with each other, and in this state, the movable stage 52 is moved back and forth to move the friction speed 10
The cloth 15 and the conductive member 14 are frictionally moved at 0 mm / min, and the friction resistance at this time is measured by the load cell 54.
From the frictional resistance value above cloth (Bencott lint free)
The friction coefficient of the conductive member 14 with respect to 15 may be obtained.
In addition, as a friction partner material, cellulose 100%, 30 g
/ M ² , 70 mesh cloth (Bencott lint free)
The reason for selecting was that the surface properties of the conductive members such as the developing member, the transfer member, and the cleaning member were most correlated,
This is because the obtained measurement range of the friction coefficient was appropriate.

[0049]

EFFECTS OF THE INVENTION The conductive member of the present invention can solve the problems of [initial fog / durable fog] and [OPC adhesion] described above, and can perform good developing operation, transfer operation, and cleaning even under severe conditions. The operation and the like can be reliably performed, and a good image can be stably obtained by using it as a developing member, a transfer member, a cleaning member, etc. of the electrophotographic apparatus.

[0050]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[Example 1] (Developing member) Polyamide "A90" (Toray) was dissolved in an ethanol solvent, and a fluororesin "Modiper F200" (Nippon Oil & Fats Co., Ltd.) composed of a fluorine-acrylic block copolymer was used as polyamide resin 100. After adding 10 parts by weight to parts by weight, a coating material A was prepared by further adding 10 parts by weight of a melamine crosslinking agent.

An elastic layer (volume resistivity: 10 ⁵ Ω) made of isoprene rubber having a resistance value adjusted by adding a conductive agent (carbon black) to the outer periphery of the metal shaft and having a thickness of 6 mm.
.Cm) to form an isoprene rubber roller.
By dipping this isoprene rubber roller in the coating material A and drying it, about 1 is applied onto the isoprene rubber elastic layer.
An outermost resin layer A having a thickness of 0 μm was formed to prepare a developing roller having the same layer structure as that shown in FIG.

The surface roughness of the obtained roller was 3.3 μm in terms of JIS ten-point average roughness Rz. In addition, when a voltage of 8 kV was applied to the corona discharger arranged with a distance of 1 mm from the roller surface to generate corona discharge and the surface was charged, the maximum surface potential after 0.3 seconds was reached. The value is 2 V, and the surface potential after 10 seconds is 0.13.
It was V. Further, using the measuring device shown in FIG. 3, this roller was subjected to a friction test using a cloth of 100% cellulose, 30 g / m ² , 70 mesh under the condition of temperature 22 ° C./humidity 50% RH. The coefficient was 0.31.

[Example 2] (Developing member) Polyamide resin "Harmide 3228" (Harima Kasei)
Was dissolved in a toluene solvent, and 4 parts by weight of perfluoroalkyl group-containing polymer type modifier "F-178RM" (Dainippon Ink) was added to 100 parts by weight of polyamide resin, and silica particles were further added. A paint B was prepared by adding 20 parts by weight of an isocyanate crosslinking agent so that the NCO index was 1.5.

An isoprene rubber roller similar to that used in Example 1 was dipped in the above paint B and dried to form an outermost resin layer B of about 10 μm on the isoprene rubber elastic layer of the roller.
To form a developing roller having the same layer structure as that shown in FIG.

The surface roughness of the obtained roller was JIS ten-point average roughness Rz of 6.6 μm. In addition, when a voltage of 8 kV was applied to the corona discharger arranged with a distance of 1 mm from the roller surface to generate corona discharge and the surface was charged, the maximum surface potential after 0.3 seconds was reached. The value is 3 V, and the surface potential after 10 seconds is 0.25.
It was V. Further, using the measuring device shown in FIG. 3, this roller was subjected to a friction test using a cloth of 100% cellulose, 30 g / m ² , 70 mesh under the condition of temperature 22 ° C./humidity 50% RH. The coefficient was 0.17.

[Example 3] (Developing member) Polyamide resin "Harmide 3228" (Harima Kasei)
Is dissolved in a toluene solvent, and a fluorocarbon resin "Kainer 7201" (Elf Atchem) is added to the polyamide resin 10
After adding 60 parts by weight to 0 parts by weight, 10 parts by weight of silica particles and an isocyanate cross-linking agent were added so that the NCO index was 1.5, to prepare coating material C.

An isoprene rubber roller similar to that used in Example 1 was dipped in the above paint C and dried to form an outermost resin layer C of about 10 μm on the isoprene rubber elastic layer of the roller.
To form a developing roller having the same layer structure as that shown in FIG.

The surface roughness of the obtained roller was 5.3 μm in JIS ten-point average roughness Rz. In addition, when a voltage of 8 kV was applied to the corona discharger arranged with a distance of 1 mm from the roller surface to generate corona discharge and the surface was charged, the maximum surface potential after 0.3 seconds was reached. The value is 14 V, and the surface potential after 10 seconds is 1.9.
It was 5V. Further, using the measuring device shown in FIG. 3, this roller was subjected to a friction test using a cloth of 100% cellulose, 30 g / m ² , 70 mesh under the condition of temperature 22 ° C./humidity 50% RH. The coefficient was 0.19.

[Comparative Example 1] (Developing member) Polyamide resin "H1060" (Sanyo Kasei) was dissolved in an ethanol solvent, and a melamine crosslinking agent was added to polyamide resin 10.
A coating material D was prepared by adding 10 parts by weight to 0 parts by weight.

An isoprene rubber roller similar to that used in Example 1 was dipped in the above coating D and dried to form an outermost resin layer D of about 10 μm on the isoprene rubber elastic layer of the roller.
To form a developing roller having the same layer structure as that shown in FIG.

The surface roughness of the obtained roller was 3.3 μm in JIS ten-point average roughness Rz. In addition, when a voltage of 8 kV was applied to the corona discharger arranged with a distance of 1 mm from the roller surface to generate corona discharge and the surface was charged, the maximum surface potential after 0.3 seconds was reached. The value is 6 V, and the surface potential after 10 seconds is 0.26.
It was V. Further, using the measuring device shown in FIG. 3, this roller was subjected to a friction test using a cloth of 100% cellulose, 30 g / m ² , 70 mesh under the condition of temperature 22 ° C./humidity 50% RH. The coefficient was 1.02.

[Comparative Example 2] (Developing member) Polyamide resin "X1860" (Daiichi Kogyo Seiyaku Co., Ltd.) was dissolved in a methanol solvent, and 10 parts by weight of a melamine crosslinking agent was added to 100 parts by weight of polyamide resin to prepare coating E. Was prepared.

An isoprene rubber roller similar to that used in Example 1 was dipped in the coating material E and dried to form an outermost resin layer E of about 10 μm on the isoprene rubber elastic layer of the roller.
To form a developing roller having the same layer structure as that shown in FIG.

The surface roughness of the obtained roller was JIS 10-point average roughness Rz of 3.4 μm. In addition, when a voltage of 8 kV was applied to the corona discharger arranged with a distance of 1 mm from the roller surface to generate corona discharge and the surface was charged, the maximum surface potential after 0.3 seconds was reached. The value is 270 V, and the surface potential after 10 seconds is 12
It was 0V. Further, using the measuring device shown in FIG. 3, this roller was subjected to a friction test using a cloth of 100% cellulose, 30 g / m ² , 70 mesh under the condition of temperature 22 ° C./humidity 50% RH. The coefficient was 0.87.

[Comparative Example 3] (Developing member) Polyamide resin "X1860" (Daiichi Kogyo Seiyaku Co., Ltd.) was dissolved in a methanol solvent, and a fluororesin "Modiper F22" composed of a fluorine-acrylic block copolymer was added thereto.
0 "(Nippon Oil & Fats Co., Ltd.) was added to 3 parts by weight of 100 parts by weight of the polyamide resin, and then 10 parts by weight of silica powder and 10 parts by weight of a melamine crosslinking agent were added to prepare coating material F.

An isoprene rubber roller similar to that used in Example 1 was dipped in the coating material F and dried to form an outermost resin layer F of about 10 μm on the isoprene rubber elastic layer of the roller.
To form a developing roller having the same layer structure as that shown in FIG.

The surface roughness of the roller obtained was JIS ten-point average roughness Rz of 7.2 μm. In addition, when a voltage of 8 kV was applied to the corona discharger arranged with a distance of 1 mm from the roller surface to generate corona discharge and the surface was charged, the maximum surface potential after 0.3 seconds was reached. The value is 350 V, and the surface potential after 10 seconds is 16
It was 0V. Further, using the measuring device shown in FIG. 3, this roller was subjected to a friction test using a cloth of 100% cellulose, 30 g / m ² , 70 mesh under the condition of temperature 22 ° C./humidity 50% RH. The coefficient was 0.29.

For the developing rollers of Examples 1 to 3 and Comparative Examples 1 to 3, OPC adhesion (adhesion) was performed by the following method.
Initial image fog, toner transportability, toner chargeability, image fog after endurance, and development roller abrasion were evaluated. The results are shown in Table 1.

[OPC adhesion (adhesion)] The roller to be tested was attached as a developing roller to the printer cartridge shown in FIG. 2, and left for 1 week under the condition of 40 ° C./80% RH, and the photosensitive drum and the developing roller were separated from each other. The adhesion was examined. [Initial image fog] A roller to be tested is mounted as a developing roller on the printer cartridge shown in FIG. 2, a developing bias voltage is set to 400 V, a non-magnetic one-component toner having an average particle size of 7 μm is used, and a peripheral speed of 60 mm / sec. The image was reproduced by reversal development while rotating at a high speed, and the image quality (presence or absence of fog and degree) in each of the initial white background, halftone, and black background images was evaluated. [Toner Conveying Property] The roller to be tested is mounted as a developing roller on the printer cartridge shown in FIG.
The toner conveyance amount was investigated by rotating at a peripheral speed of / sec to form a uniform thin toner layer on the surface of the developing roller, sucking the thin toner layer, and measuring the weight. [Toner chargeability] A roller to be tested is mounted as a developing roller on the printer cartridge shown in FIG.
It was rotated at a peripheral speed of / sec to form a uniform thin toner layer on the surface of the developing roller. The thin toner layer was sucked and introduced into a Faraday gauge, and the amount of charge was measured. [Image Fogging After Durability] After the above-mentioned [initial image fogging] test, a durability test of 10,000 sheets was performed, and then the same image evaluation was performed. [Abrasion of Developing Roller] The tested roller after the durability test was taken out, and the surface of the roller was observed with a video microscope to evaluate the degree of scratches and abrasion.

[0071]

[Table 1] Evaluation criteria : Very good ○ △: Good △: Normal △ ×: Not very good ×: Poor

[Example 4] (Transfer member) Polyamide resin "L203" (Sanyo Kasei Co., Ltd.) was dissolved in an ethanol solvent, and a fluororesin "Modiper F220" composed of a fluorine-acrylic block copolymer was further prepared.
5 parts by weight of (NOF CORPORATION) was added to 100 parts by weight of polyamide resin, and then 5 parts by weight of carbon powder,
A coating material G was prepared by adding 10 parts by weight of a melamine crosslinking agent.

On the outer circumference of the metal shaft, a 5 mm-thick elastic layer (volume resistivity 10 ⁷ ) made of urethane foam whose resistance value was adjusted by adding a conductive agent (carbon black).
Ω · cm) to form a urethane foam roller. This urethane foam roller is dipped in the coating material G and dried to form an outermost resin layer G having a thickness of about 10 μm on the urethane foam elastic layer, as shown in FIG.
A transfer roller having a layer structure similar to that of was prepared.

A roller was prepared in the same manner except that the conductive agent carbon was not added to the outermost resin layer G.
When a voltage of 8 KV was applied to the corona discharger arranged at a distance of 1 mm from this roller surface to generate corona discharge and the surface was charged, the maximum value of the surface potential after 0.3 seconds was It was 3 V, and the surface potential after 10 seconds was 0.32 V. Also, using the measuring device shown in FIG. 3, this roller was subjected to a friction test using a cloth of 100% cellulose, 30 g / m ² , 70 mesh under the condition of temperature 22 ° C./humidity 50% RH. The coefficient is 0.19
Met.

[Comparative Example 4] (Transfer member) Polyamide resin "X1850" (Sanyo Kasei Co., Ltd.) was dissolved in an ethanol solvent, and carbon powder was added in an amount of 10 parts by weight per 100 parts by weight of polyamide resin, and 1 part of a melamine crosslinking agent was added.
A paint H was prepared by adding 0 part by weight.

A urethane foam roller similar to that used in Example 4 was dipped in the coating material H and dried to form an outermost resin layer H of about 10 μm on the urethane foam elastic layer of the roller. A transfer roller having the same layer structure as in (A) was prepared.

A transfer roller was prepared in the same manner except that the conductive agent carbon was not mixed with the outermost resin layer H, and a voltage of 8 kV was applied to a corona discharger arranged at a distance of 1 mm from the roller surface. When the voltage was applied to generate corona discharge to charge the surface, the maximum value of the surface potential after 0.3 seconds was 250V, and the surface potential after 10 seconds was 120V. Also, using the measuring device shown in FIG. 3, this roller was subjected to a friction test using a cloth of 100% cellulose, 30 g / m ² , 70 mesh under the condition of temperature 22 ° C./humidity 50% RH. The coefficient was 0.85.

The transfer rollers of Example 4 and Comparative Example 4 were pressed against the photosensitive drum with a load of 1 kg, and the temperature was 50 ° C./humidity was 8
When the roller of Example 4 was left in an environment of 5% RH for 2 weeks, no particular problem occurred with the roller of Example 4, while Comparative Example 4
There was sticking and contamination between the roller and the photosensitive drum. Further, when both transfer rollers were set in a laser beam printer and 5,000 sheets of images were printed, no particular problem was found with the roller of Example 4, but with the roller of Comparative Example 4, the toner on the roller surface was Due to stains, blank characters in the image and stains on the back surface of the transfer paper occurred.

[Embodiment 5] (Cleaning member) An elastic layer (1.0 × 10 ³ Ω · c) formed on the outer periphery of a metal shaft and made of conductive urethane foam having a thickness of 3 mm.
m), the following intermediate resin layer I having a thickness of 100 μm is formed, and further the outermost resin layer J having a thickness of 10 μm described below is formed on the surface, and the layer structure is the same as that of FIG. 1B. Created a cleaning roller.

Intermediate resin layer I A coating material H prepared by adding carbon to an aqueous acrylic resin is applied by a dipping method, and has a volume resistivity of 5 × 10 ^7.
Adjusted to Ω · cm. Outermost resin layer J Polyamide resin "Harmide 3228" (Harima Kasei)
Is dissolved in a toluene solvent, and a fluororesin "MODIPER F" composed of a fluorine-acrylic block copolymer
200 "(Nippon Oil & Fats Co., Ltd.) was added to 10 parts by weight of 100 parts by weight of the polyamide resin, and then an isocyanate cross-linking agent was further added so that the NCO index became 1.5. Was applied by a dipping method.

The surface roughness of the resulting roller was JIS ten-point average roughness Rz of 0.9 μm. In addition, when a voltage of 8 kV was applied to the corona discharger placed with a distance of 1 mm from the roller surface to generate corona discharge and the surface was charged, the maximum surface potential after 0.3 seconds was reached. The value is 6 V, and the surface potential after 10 seconds is 0.2.
It was 9V. Further, using the measuring device shown in FIG. 3, this roller was subjected to a friction test using a cloth of 100% cellulose, 30 g / m ² , 70 mesh under the condition of temperature 22 ° C./humidity 50% RH. The coefficient was 0.18.

When the above cleaning roller was mounted on a printer cartridge and left for 2 weeks in an environment of temperature 40 ° C./humidity 95% RH, sticking to the photosensitive drum was not observed. In addition, a good image was obtained when an image was printed using the cartridge, and a continuous image was obtained.
No image deterioration was observed even when 0 images were printed.

[Comparative Example 5] (Cleaning member) An intermediate resin layer I similar to that of Example 4 was formed on the surface of an elastic layer similar to that of Example 5, and the following outermost resin having a thickness of 10 μm was formed thereon. Layer K was formed to prepare a cleaning roller having the same layer structure as that shown in FIG.

Outermost Resin Layer K Polyamide resin “X1850” (Sanyo Kasei) was dissolved in an ethanol solvent, and a coating K was prepared by adding 10 parts by weight of carbon and 10 parts by weight of melamine crosslinking agent to 100 parts by weight of polyamide resin. It was formed by coating by the dipping method.

The surface roughness of the obtained roller is JIS ten-point flatness.
The average roughness Rz was 0.8 μm. Also, the outermost tree above
The same except that the conductive agent carbon is not mixed in the fat layer K
To make a cleaning roller, and
A corona discharger placed at a distance of m
Apply voltage to generate corona discharge and charge the surface
The maximum surface potential after 0.3 seconds was 22
0V, and the surface potential after 10 seconds was 100V.
It was Further, using the measuring device shown in FIG.
Cellulose 100 under conditions of temperature 22 ° C / humidity 50% RH
%, 30 g / m ², 70 mesh cloth for friction test
The coefficient of friction was 1.21.

When the cleaning roller was attached to a printer cartridge and left for 2 weeks in an environment of temperature 40 ° C./humidity 95% RH, sticking to the photosensitive drum occurred. In addition, when an image was printed using the cartridge, one stripe pattern was contaminated in the lateral direction at the photosensitive drum cycle. Further, in the image display, white background fogging occurred due to poor cleaning.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view illustrating a conductive member according to the present invention.

FIG. 2 is a schematic view showing an example of an electrophotographic apparatus using the conductive member of the present invention.

FIG. 3 is a schematic view showing an example of a measuring device for measuring a friction coefficient on the surface of a conductive member.

FIG. 4 is a schematic view showing an example of an apparatus for measuring a surface charging potential characteristic of a conductive member.

[Explanation of symbols]

1 shaft 2 elastic layer 3 outermost resin layer 4 Intermediate resin layer 5 Photosensitive drum (latent image holder) 6 Developing roller (developing member) 7 Developing device 8 Transfer paper 9 Transfer roller (transfer member) 11 Cleaning roller (cleaning member) 12 Cleaning device 13 Fixer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/08 501 G03G 15/08 501D 4J002 15/16 103 15/16 103 21/10 21/00 312 F Term (reference) 2H071 BA43 DA08 DA09 DA13 2H077 AD06 FA13 FA16 FA22 FA26 FA27 GA03 2H134 GA01 GB02 HA03 KD04 KD12 KE01 KE02 KE06 KH01 KH15 2H200 FA02 FA16 GB50 HA02 HB12 H0445 HB46 HB47 JA02 MA13 MA04 MA14 JA27 JA04 JA14 JA27 JA27 JA26 MA27 JA27 JA04 MA27 MC05 3J103 AA02 AA14 FA18 GA57 GA58 HA03 4J002 BD14X BD15X BD16X BE04X BG08X BN17W CL00W DA036 FD116 GQ02

Claims (7)

[Claims] 1. A conductive member used in an electrophotographic apparatus, comprising an elastic layer and at least one formed on the elastic layer.
And a resin material in which the outermost resin layer constituting the member surface contains 50% by weight or more of a polyamide resin and 50% by weight or less of a fluororesin component and / or a fluorine compound component. Is a conductive member formed by
In addition, in a state where the outermost resin layer does not contain any conductive agent, a voltage of 8 kV is applied to a corona discharger arranged at a distance of 1 mm from the surface of the outermost resin layer to generate corona discharge, and the corona discharge is generated. When the outer resin layer surface is charged,
A conductive member having a maximum surface potential of 50 V or less after 0.3 seconds and a surface potential of 5 V or less after 10 seconds. 2. The content of the polyamide resin in the resin material forming the outermost resin layer is 50 to 99.9% by weight, and the content of the fluororesin component and / or the fluorine compound component is 0.1.
The conductive member according to claim 1, which is ˜50% by weight. 3. Cellulose 100%, 30 g / m ² , 7
The friction coefficient with respect to the cloth of 0 mesh is 0.5 or less when the cloth is pressed against the cloth with a load of 100 gf.
Or the conductive member according to 2. 4. A resin material for molding the outermost resin layer,
The conductive member according to claim 1, further comprising a conductive powder. 5. A developer is carried on the surface of the conductive member according to claim 1 to form a thin film of the developer, and an electrostatic latent image is held on the surface in this state. An electronic device comprising a developing device for visualizing the electrostatic latent image by bringing the developer into contact with the latent image carrier to adhere the developer to the electrostatic latent image on the surface of the latent image carrier. Photographic equipment. 6. A transfer device for charging the transfer paper with the conductive member according to claim 1, and transferring the developer from the electrostatic latent image visualized by the developer onto the transfer paper. An electrophotographic apparatus characterized by the following. 7. An electrophotographic apparatus comprising a cleaning device for removing the developer remaining on the latent image holding member by the conductive member according to claim 1. Description: