JPH09101650A - Electrostatic charging member, process cartridge having this electrostatic charging member and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrostatic charging member which has an excellent contact property, hardly chips the surface of a member to be electrostatically charged, is repetitively usable and is suitable for implanted electrostatic charge by having a fiber interlinked member subjected to napping on a conductive base body and a surface layer in contact with the member to be electrostatically charged. SOLUTION: The electrostatic charging brush 1 is constituted by winding the fiber interlinked member 3 subjected to napping around the conductive base body (ambor). There are a method of spirally winding the fiber interlinked member of a short width around the base body and a method of lining the arbor of a wide width corresponding to the width of the electrostatic charging member with this fiber interlinked member. The fibers to be used are synthetic fibers, natural fibers, semisynthetic fibers, regenerated fibers, etc. Any fiber interlinked members are usable, insofar as these members are napped. Such members may be a woven fabric and non-woven fabric. The method for napping includes a buffing treatment by sandpaper, brushing treatment by rigid brushed, etc. The contact area with a photoreceptor is increased by napping the fiber interlinked member and, therefore, the electrostatic charge is made uniform under a low contact pressure condition. Further, the napped fiber tips are sharpened and the electrostatic chargeability is exceedingly improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging member for forming an image, and more particularly, to a contact charging member which is brought into contact with a member to be charged and a voltage is applied to uniformly charge the member.

The present invention also relates to a process cartridge having the above charging member and an electrophotographic apparatus.

[0003]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic device, a corona charging device and a contact charging device are used as a device for charging a charged body such as an electrophotographic photosensitive member.

The contact charging device is a device that applies a DC voltage or an oscillating voltage obtained by superimposing an AC voltage on a DC voltage to a charging member brought into contact with a member to be charged so as to charge the member to be charged.

In such a contact charging device, as disclosed in, for example, Japanese Patent Application Laid-Open No. 63-149669, when a direct current voltage is applied to the contact charging member, the charging start voltage of the member to be charged is at least twice the charging start voltage. By forming an oscillating electric field having a peak-to-peak voltage between the contact charging member and the body to be charged, the body to be charged can be charged.

An example of the structure of the contact charging member will be shown below.

FIG. 5 is a vertical sectional view of a charging roller as a charging member. The charging roller 10 includes a conductive substrate 11 that is a supporting member (core metal), a conductive elastic layer 13 having elasticity necessary to form a uniform nip with the surface of the body to be charged,
The charging roller 10 includes a medium resistance charging layer 12 that controls the resistance of the charging roller 10.

The elastic layer 13 is a conductor in which a conductive filler such as a metal oxide or carbon black is dispersed in a solid rubber such as acrylic rubber, urethane rubber or silicone rubber.

The charging layer 12 is generally a medium resistance member, and is constructed so that charging defects do not occur in the image area even if defects such as pinholes occur in the member to be charged. The charging layer as a medium resistor is a resin such as acrylic resin, nylon, polyester, polyurethane, phenol resin and styrene resin in which a metal oxide such as titanium oxide or tin oxide or a conductive filler such as carbon black is dispersed. The mixed solution is coated on the surface by means such as dipping coating, spray coating and roller transfer coating.

Next, as an explanation of the image forming apparatus equipped with the above contact charging roller, an example of the construction of a laser beam printer adopting the reversal developing method will be shown.

First, FIG. 6 shows the structure of the contact charging device 20. The charging roller 10 is a photosensitive member 2 that is a member to be charged
1 is disposed substantially in parallel with the photosensitive drum 1 and is pressed against the photosensitive member with a constant contact nip width. Here, the pressure contact is performed by the pressure springs 22 located at both ends of the conductive base of the charging roller.
In this pressured state, the charging roller is driven to rotate by the photoconductor rotating at a predetermined process speed to sequentially charge the surface of the photoconductor. Here, 23 is a power supply.

FIG. 7 is a schematic view of a laser beam printer having a process cartridge having the contact charging member. The photoconductor 21 charged by the contact charging member 10 is scanned and exposed by the laser light 31 to form an electrostatic latent image on the photoconductor surface. The electrostatic latent image is developed (reverse development) as a toner image by the developing device 32, and the toner image is transferred to the transfer material 34 fed to the pressure contact portion between the transfer device 33 and the photoconductor. The transfer residual toner on the photoconductor is removed by the cleaning device 35, and the photoconductor is prepared for the next image formation. The transfer material onto which the toner image has been transferred is conveyed to the fixing device 36, where the toner image is fixed, and then the copy material is discharged to the outside of the apparatus. The electrophotographic photoreceptor 21, the charging member 10, the developing device 32, and the cleaning device 35 are integrally supported, and the process cartridge 3 is supported.
As a reference numeral 7, a guide means such as a rail 38 is used so as to be attachable to and detachable from the printer body.

[0013]

By the way, if the contact charging member having the charging layer composed of the resin and the conductive filler is used for a long period of time, the photoreceptor may be worn and the charging property may be deteriorated. It was

It has been pointed out that one of the causes of wear is the pressure contact rotation of the contact charging member. However, in the case of contact charging, it is necessary to uniformly contact the photoconductor of the charging member in order to obtain sufficient chargeability. Therefore, it is necessary to apply a certain amount of pressure to the photoconductor of the charging member. ing.

Further, when the transfer residual toner or shavings of the photoconductor adheres to the surface of the contact charging member, the surface resistance of the charging member may change and the charging property may be deteriorated.

US Pat. No. 4,371,252 and Japanese Unexamined Patent Publication (Kokai) No. 6-27409 disclose a charging member made of conductive fiber. In the member constitution, the former is a base, an elastic layer, an electrode layer and a contact layer, and is composed of a contact layer or a conductive fiber assembly that contacts the photoreceptor and charges. The latter is composed of a conductive holder, an elastic core material, and a conductive non-woven fabric that comes into contact with the photoconductor. The fibrous member is less likely to wear the photoreceptor than the resin layer described above, and therefore is expected to prevent surface abrasion.

However, in general, the fibers in a spun state have a low contact property with an object to be charged, and in many cases, a sufficient charge property cannot be obtained. Therefore, in the contact charging by the fiber member,
At present, it is possible to prevent the deterioration of the charging property by increasing the contact pressure with the body to be charged or widening the contact area (nip). Therefore, it has been difficult to prevent the surface abrasion of the photoconductor for a long time. Further, it has been pointed out that when the transfer residual toner or the like adheres to the fibrous member due to insufficient contact with the photoconductor, the charging property is lowered.

Further, a charging member using an elastic layer made of low hardness rubber or a foam, which can obtain sufficient contact even with a low pressure contact force, has been proposed for the purpose of preventing the surface of the photoconductor from being scraped. By reducing the hardness of the elastic layer, abrasion of the photoconductor tends to be mitigated compared to conventional products, but fundamental abrasion is prevented due to the effect of friction between the charging layer made of a resin layer and the photoconductor. Has not reached.

On the other hand, the contact charging is the usual one using discharge, and those disclosed in JP-A-6-3921 and JP-A-7-574.
A charge injection layer is provided as a surface layer of a photoreceptor as described in Japanese Patent Publication No. 8 and the like, and is roughly classified into injection charging in which charges are directly injected from a charging member to the layer. Since injection charging does not utilize discharge, it is extremely excellent in terms of reduction of applied voltage and prevention of generation of ozone products.

However, in the case of injection charging, since the charge is injected only at the contact point between the charging member and the injection point of the charge injection layer, the influence of the contact property of the charging member on the charging property is larger than that of ordinary contact charging. And it will be very big. Therefore, in the case of injection charging, the conventional charging member whose surface is a resin layer or a normal brush contactor as described above has a more remarkable problem of a decrease in charging property due to difficulty in obtaining sufficient contact property. It is easy to occur.

Therefore, an object of the present invention is to provide a charging member which is excellent in contact with a member to be charged.

It is another object of the present invention to provide a charging member that does not easily scrape the surface of the body to be charged.

Another object of the present invention is to provide a charging member which can uniformly charge an object to be charged even if it is repeatedly used.

Another object of the present invention is to provide a process cartridge and an electrophotographic apparatus having the above charging member.

[0025]

That is, the present invention relates to a charging member which is disposed in contact with a body to be charged and which charges the body to be charged by applying a voltage to a conductive substrate and the body to be charged. A charging member having a surface layer in contact with the fiber, and the surface layer having a entangled fiber entangled body.

The present invention also provides a process cartridge and an electrophotographic apparatus having the above charging member.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The fiber entangled body used in the present invention may be any one as long as it is raised, and may be a woven fabric or a non-woven fabric.

Examples of the raising method include buffing treatment with sandpaper and brushing treatment with a rigid brush. In the present invention, raising the fiber entangled body increases the contact area with the photoconductor, so that charging can be made uniform under low contact pressure conditions. Furthermore, the tips of the napped fibers are sharpened, and the chargeability is dramatically improved.

The fibers used in the present invention include synthetic fibers, natural fibers, semi-synthetic fibers and regenerated fibers. To give a specific example, first, as synthetic fibers, for example, nylon-6, nylon-66, nylon-12, nylon-
46, polyamides such as aramids, polyesters such as polyethylene terephthalate (PET), polyolefins such as polyethylene (PE) and polypropylene (PP), polyvinyl alcohols, polyvinyl chloride and vinylidene, polyacrylonitrile, polyphenylene Examples include sulfide, polyurethane, polyfluoroethylene, carbon fiber and glass fiber. Examples of natural fibers include silk, cotton, wool, and hemp. Acetate, etc. as semi-synthetic fiber, and as regenerated fiber,
There are rayon and cupra. Furthermore, a composite fiber obtained by compounding two or more kinds of synthetic fiber raw material components and melt spinning can be used. These fibers can be used alone or in combination of two or more kinds.

In the present invention, it is preferable to use an ultrafine fiber-forming conjugate fiber. This is because it is possible to easily achieve a high density of raised hair, and since the fiber entangled body composed of ultrafine fibers has high strength and excellent durability as a member, more uniform charging can be obtained for a long period of time. Therefore,
The effect of the present invention is particularly remarkable when applied to injection charging. Such ultrafine fiber-generating composite fibers can be used alone or in combination of two or more kinds. Furthermore, it can be used in combination with the above-mentioned fibers.

The ultrafine fiber-generating composite fiber is preferably an etching fiber or a split fiber.

The etching fiber in the present invention is a fiber obtained by chemically removing only a specific component from a plurality of components with an acid or an alkali, and is a synthetic fiber, a natural fiber, a semi-synthetic fiber or a regenerated fiber. Fiber etc. are mentioned.

In the present invention, a composite fiber obtained by composite spinning of two or more kinds of the above-mentioned fiber raw materials is used. Examples of the chemically-etchable conjugate fiber include core-sheath fiber that can obtain a single ultrafine fiber, and sea-island fiber that can obtain a plurality of ultrafine fibers. These composite fibers are, for example, fibers obtained by composite-spinning a polyester-based hydrolyzable resin and a polyamide-based, polyolefin-based, polyacrylic-based, or other non-hydrolyzable resin. A fiber made of a hydrolyzable resin is obtained. Other hydrolyzable resins include composite fibers of solvent-soluble resin and insoluble resin.

For example, in the case of sea-island fiber, the sea part is made of PET, which is a hydrolyzable resin, and the plural island parts are made of nylon-6, which is a non-hydrolyzable resin, and hydrolyzed with an alkaline aqueous solution of sodium hydroxide or potassium hydroxide. As a result, the PET component in the sea is decomposed and removed, and a plurality of nylon-6 islands are obtained as ultrafine fibers.

On the other hand, the split fiber in the present invention is a fiber obtained by splitting by utilizing a difference in heat shrinkage ratio or an external force, and is a synthetic fiber, a natural fiber or a semi-synthetic fiber as described above. Examples include fibers and recycled fibers.

Specifically, the incompatible thermoplastic resin is subjected to composite spinning, followed by stretching and heat treatment, and when heated, it is opened and divided due to the difference in shrinkage ratio of each part. Here, as the combination of the incompatible thermoplastic resins, for example, one is polyester and the other is nylon or polypropylene.

Further, the fibers are opened into ultrafine fiber groups by high-pressure water jet or needle punching method. In this case, it is possible to use the ultrafine fiber-generating composite fiber utilizing the above-mentioned heat shrinkage so that the fiber can be opened more efficiently. Here, as a combination of incompatible thermoplastic resins,
For example, one is polyester and the other is nylon or polypropylene.

Since the etching fibers and the split fibers have fine irregularities on the fiber surface, they have a very high contact property with the member to be charged and can be uniformly charged. The effect is particularly remarkable when applied to injection charging.

In the present invention, the number (segment number) and fineness of the ultrafine fibers obtained from the ultrafine fiber-generating composite fiber are
Although not particularly limited, in consideration of long-term fiber durability, it is preferable that the number of segments is 1 to 100 and the average fiber diameter is 0.05 μm to 20 μm. The average fiber diameter is a value obtained by averaging the respective measured values obtained by performing electron microscope photography, arbitrarily selecting 10 locations, and further measuring 10 fiber diameters at each location.

In the present invention, the fiber resistance R of the charging layer is
Is preferably 1 × 10 ³ Ω ≦ R ≦ 1 × 10 ⁹ Ω.

When the resistance R is smaller than 1 × 10 ³ Ω,
Leakage may occur in the photoconductor when there is a pinhole, and in that case, charging becomes defective. If the resistance R is larger than 1 × 10 ⁹ Ω, uniform charging becomes difficult.

Here, the resistance is a value calculated from the current value when DC100V is applied to the conductive metal rotating body.

As the method for making the fibers conductive, for example, 1) a method of using conductive fibers obtained by spinning a fiber raw material in which a conductive filler is dispersed, 2) a conductive electron-conjugated polymer (hereinafter referred to as conductive) A method of applying a polymer) to the fiber surface, 3) a method of applying a binder resin in which a conductive filler is dispersed to the fiber surface, and the like. Among them, it is preferable to use the conductive polymer of 2). . The conductive polymer may be used alone or in combination with the above 1) and / or 3).

In the above 1), the conductive fiber may be used alone, but the entangled body may be made conductive by being mixed and entangled with the non-conductive-treated fiber.

Preferred examples of the above conductive polymer include polypyrrole, polythiophene, polyquinoline, polyphenylene, polynaphthylene, polyacetylene, polyphenylene sulfide, polyaniline, polyphenylene vinylene, and polymerized products of these monomer derivatives. A combination of more than one type can be used.

Preferable examples of the binder resin include olefin resin, acrylic resin, polyurethane resin, phenol resin, nylon resin, polyester resin, and the like, and preferable examples of the conductive filler are aluminum and tin. , Metal powders and fibers such as iron and copper, metal oxides such as zinc oxide, tin oxide and titanium oxide, metal sulfides such as copper sulfide and zinc sulfide, and carbon powders such as carbon black. .

The conductive agent can be coated on the fibers by solution coating or vapor phase coating. For example, in the case of a binder resin solution in which a conductive polymer dissolved in a solvent or a conductive filler is dispersed, the solution can be impregnated with fibers, or the solution can be applied to the fibers by means such as spray coating or roller coating. . Further, the surface of the fiber can be coated with the conductive polymer by bringing the monomer, which is the precursor of the conductive polymer, into contact with the fiber which has been subjected to the catalyst treatment in advance. Here, the monomer can be in contact with either vapor or liquid.

In the present invention, examples of the method for conducting the fibers electrically conductive include a method for electrically conducting the fibers immediately after spinning, a method for electrically conducting the fibers after being processed into a fiber entangled body.

Examples of the conductive substrate used in the present invention include metals and alloys such as aluminum, aluminum alloys and stainless steel, and resins in which conductive particles such as conductive carbon black, metal and conductive metal oxide are dispersed. Can be mentioned. Examples of the shape include a rod shape and a blade shape such as a flat plate or a V-shaped plate.

In the present invention, a conductive elastic layer can be provided between the surface layer and the conductive base. Examples of the elastic material used include EPDM, NBR, butyl rubber, acrylic rubber, urethane rubber, polybutadiene, butadiene styrene rubber, butadiene acrylonitrile rubber, polychloroprene, polyisoprene, chlorosulfonated polyethylene, polyisobutylene, isobutylene isoprene rubber, fluororubber. And synthetic rubber such as silicone rubber and natural rubber. These elastic materials may be foamed to an appropriate cell diameter by using a foaming agent or the like, if necessary. The elastic material can be easily made conductive by a conductive filler, and examples of such a conductive filler include aluminum, nickel, stainless steel,
Powders and fibers of metal such as palladium, zinc, iron, copper and silver, composite metal powder such as zinc oxide, tin oxide, titanium oxide, copper sulfide and zinc sulfide, and acetylene black, Ketjen black, PAN carbon And carbon powder such as pitch-based carbon, which may be used alone or in combination of two or more kinds.

Examples of the form of the charging member having the brush contact of the present invention include a roller shape, a blade shape, and a belt shape. Among them, the roller shape and the belt shape are preferable. Below, the structural example of the charging member of this invention is shown.

FIG. 1 shows a charging roller 1. This is a configuration in which the raised fiber entangled body 3 is wound around the conductive base body (core bar) 2. Examples of the winding means include a method of winding a short entangled fiber entangled body in a spiral shape and a method of attaching a wide woven fabric corresponding to the width of the charging member to a core metal. Further, FIG. 2 shows an example in which a conductive elastic layer is provided between the conductive substrate 2 and the surface layer 3.

FIG. 3 shows a charging blade having a construction in which a raised fiber entangled body 3 is attached to a blade-shaped conductive substrate 2. The blade can also vibrate forward, backward, leftward and rightward on the surface of the photoconductor by connecting a vibrator (not shown).

FIG. 4 shows a belt-shaped charging member. 3
Is a raised fiber entangled body, and 2 is a belt-shaped conductive base made of conductive rubber, which is fixed and rotated by a driving roll 6 and a driven roll 5. As the belt, in addition to the two-axis type fixed belt shown in FIG. 4, the driven roll position of FIG. 4 is replaced with a three-axis type fixed belt in which a driven roll is newly installed or a fixed belt of three or more axes is adopted. It is also possible.

The photosensitive member as the member to be charged used in the present invention may be any one, and it has at least a photosensitive layer on a conductive support and, if necessary, a protective layer or a charge injection layer on the photosensitive layer. Can be provided.

The charge injection layer has a volume resistance value of 1 in order to obtain sufficient chargeability and satisfy the condition that image deletion does not occur.
It is preferably adjusted in the range of × 10 ⁸ Ωcm to 1 × 10 ¹⁵ Ωcm. Especially, from the viewpoint of preventing image deletion, 1 ×
A ¹⁰ 10 Ωcm~1 × 10 ¹⁵ Ωcm, more so that the image flow and charging failure does not occur even under a rapid environmental change, is preferably ^{1 × 10 12 Ωcm~1 × 10 15} Ωcm.

Here, if the volume resistance value is smaller than 1 × 10 ⁸ Ωcm, the electrostatic latent image cannot be held and image deletion easily occurs, and if the resistance value is larger than 1 × 10 ¹⁵ Ωcm, the charge from the charging member is increased. Cannot be sufficiently received, and there is a tendency for charging failure to occur.

Regarding the volume resistance of the charge injection layer, a charge injection layer was formed on polyethylene terephthalate (PET) having a conductive film vapor-deposited on its surface, and this was measured at 23 ° C. by a volume resistance measuring device (4140B pAMASTER manufactured by Hewlett Packard). , By applying a voltage of 100 V in an environment of 65%.

As the charge injection layer of the present invention, 1) a resin layer in which an appropriate amount of light-transmissive and conductive particles are dispersed in an insulating binder resin, 2) an inorganic layer composed of a semiconductor or the like, 3 ) An organic layer made of a conductive polymer can be used.

By providing such a charge injection layer on the surface of the photoreceptor, 90% of the charge applied from the charging member can be obtained.
It plays the role of maintaining the above high efficiency, and at the time of image exposure, plays a role of releasing this electric charge to the photoreceptor support, and can reduce the residual potential.

The charge injection layer will be specifically described.

First, in the case of the resin layer composed of the conductive fine particles and the binder resin described in 1) above, the binder resin includes polyester resin, polycarbonate resin, polystyrene resin, fluororesin, cellulose, vinyl chloride resin, polyurethane resin, Resins such as acrylic resin, epoxy resin, silicone resin, alkyd resin and vinyl chloride-vinyl acetate copolymer resin can be used. Examples of the conductive fine particles include metals such as copper, aluminum, silver and nickel, zinc oxide, tin oxide, antimony oxide, titanium oxide, or metal oxides such as solid solutions or fusion materials thereof, polyacetylene, polythiophene, polypyrrole, etc. Although the conductive polymer of 1) can be used, it is more preferable to selectively use a metal oxide such as tin oxide having a high transparency from the viewpoint of the translucency of the photoreceptor.

The particle size of these conductive fine particles is preferably 0.3 μm or less, and particularly preferably 0.1 μm or less, from the viewpoint of translucency. When contained in the charge injection layer, the content of the conductive fine particles is preferably in the range of 2 to 280% by weight with respect to the binder resin, although it depends on the particle size. If the content is less than 2% by weight, it may be difficult to adjust the resistance of the charge injection layer, and if it exceeds 280% by weight, the coating property of the binder resin may be partially deteriorated.

Various additives can be added for the purpose of improving the dispersibility of the conductive fine particles, the adhesiveness with the binder resin, or the smoothness of the coating film after film formation. Further, for improving the dispersibility, it is very effective to modify the surface of the conductive fine particles with a coupling agent or a leveling agent. Further, from the viewpoint of improving dispersibility, it is effective to use a curable resin as the binder resin.

When the curable resin is used in the charge injection layer, the conductive fine particles are dispersed in a solution of a curable monomer or oligomer, a subbing coating solution is applied onto the photosensitive layer, and a film is formed. The coating film is cured to form the surface layer.
Examples of such curable resin include acrylic resin,
Examples thereof include an epoxy resin, a phenol resin, and a melamine resin. However, the resin is not limited to this, and any resin can be used as long as it undergoes a chemical reaction and cures by applying energy such as light or heat after coating and film formation.

The charge injection layer is obtained by coating and drying on a photoreceptor a suitable solution or dispersion solution containing a binder resin, conductive fine particles and additives if necessary. Preferably 0.1 to 10 μm, especially 0.5
It is preferably about 5 μm.

Here, the charge injection layer may contain a lubricant powder. Friction between the photoconductor and the charging member or friction between the photoconductor and the cleaning member is reduced, and the mechanical load on the electrophotographic apparatus can be reduced. In addition, since the releasability of the photoreceptor surface is improved, adhesion of developer particles (toner) can be prevented. As such lubricant particles, it is preferable to use a fluororesin, a silicone resin or a polyolefin resin having a low critical surface tension. Particularly preferred is a tetrafluoroethylene resin. In this case, the amount of the lubricant powder added is preferably 2 to 50% by weight with respect to the binder resin,
More preferably, it is 5 to 40% by weight. If it is less than 2% by weight, the effect of improving the charging property is not sufficient, and if it exceeds 50% by weight, the image resolution and the sensitivity of the photoreceptor tend to be lowered.

Next, as the charge injection layer made of the above inorganic material, the semiconductor such as amorphous silicon can be used.

The photoconductor made of silicon can be continuously produced by the plasma chemical vapor deposition apparatus by the high frequency glow discharge decomposition by selecting the photoconductive amorphous silicon for the lower photoconductive layer.

Examples of the charge injection layer made of the conductive polymer of 3) above include electron-conjugated polymers such as polypyrrole, polythiophene and polyaniline, and organic polysilanes.

The photosensitive layer of the present invention may be a laminated type having a charge generating layer and a charge transporting layer or a single layer type containing a charge generating substance and a charge transporting substance in the same layer. Here, the thickness of the charge transport layer is 5 to 40 μm, and the thickness of the charge generation layer is 0.0
It is preferable to set in the range of 5 to 5 μm.

Examples of the charge generating substance include organic materials such as phthalocyanine pigments and azo pigments and inorganic materials such as silicon compounds.

Examples of the charge transport material include hydrazone compounds, styryl compounds, triarylamine compounds and triarylmethane compounds.

Further, an intermediate layer may be provided between the charge injection layer and the photosensitive layer or between the conductive support and the photosensitive layer.
The intermediate layer is intended to enhance the adhesiveness of each layer or to function as a charge barrier layer. For the intermediate layer, resin materials such as epoxy resin, polyester resin, polyamide resin, polystyrene resin, acrylic resin and silicone resin can be used.

As the conductive support for the photoconductor,
Metals such as aluminum, nickel, stainless steel and steel, plastic or glass with conductive film,
Conductive paper or the like can be used.

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

[0077]

Examples Example 1 Polyethylene terephthalate and nylon-
A plain weave sheet was prepared using orange-type split fibers (number of filaments 8; average fiber diameter 1 μm) consisting of 6 and nylon-6 fibers (single fiber, fiber diameter 30 μm). A high-pressure water stream was sprayed on this to open the split fibers, which were then napped with sandpaper.

Next, the fluffed fiber sheet was impregnated with an aqueous solution of ferric chloride having a concentration of 15% by weight for 1 hour, then placed in a closed container filled with pyrrole monomer vapor, and a polymerization reaction was carried out for 2 hours to obtain a fiber surface. To form polypyrrole.
After the reaction, it was sufficiently washed with pure water and ethanol and dried at 100 ° C. With respect to the dried fiber sheet, the brushed portion was brushed with a rigid brush to make the hair uniform. The resistance of the raised fiber sheet thus obtained was 5 × 10 ⁶ Ω.

The napped fiber sheet was processed into a strip having a width of 1 cm, and was spirally wound on a stainless steel core bar having a diameter of 12 mm to prepare a charging roller.

Here, the portion cut into strips is fixed with a urethane binder so that hair does not fall off.

(Example 2) A plain weave sheet of sea-island type fibers comprising polyethylene terephthalate in the sea part and polyethylene (25 filaments, fiber diameter of the island part 0.5 μm) in the island part was dipped in an aqueous sodium hydroxide solution at 85 ° C to expose the sea part. Hydrolysis treatment was performed to generate polyethylene ultrafine fibers. Using this, a charging roller was produced in the same manner as in Example 1. Here, the resistance of the raised fiber sheet is 3 × 10 ^6.
Ω.

(Example 3) Split fiber composed of polyethylene terephthalate and polypropylene (number of filaments: 1)
6. Conductive acrylic fiber (fiber diameter 0.8 μm) and conductive carbon dispersed (single fiber, fiber diameter 30 μm, resistance 1
A plain weave woven fabric was prepared from × 10 ⁴ Ω). A high-pressure water stream was sprayed on this to open the split fibers, which were then napped with sandpaper. Further, the surface of the napped fiber sheet was brushed with a rigid brush to make the naps of the napped portion uniform. The resistance of the raised fiber sheet was 2 × 10 ⁷ Ω.

Next, a layer of EPDM foam (average foam cell diameter 100 μm) in which carbon black and tin oxide as a conductive agent were mixed and dispersed in a metal core (conductive substrate) made of stainless steel and having a diameter of 6 mm With outer diameter 1
A charging roller was produced by winding it around a conductive elastic roller of 2 mm.

(Example 4) A raised fiber sheet similar to that in Example 1 was attached to the blade-shaped stainless steel substrate (thickness: 2 mm) so as to cover the contact surface of the photoreceptor, to prepare a charging blade.

(Example 5) Split fibers composed of polyethylene terephthalate and 6 nylon (8 filaments, fiber diameter 1 µm) were washed with dilute hydrochloric acid and then immersed in a 20% by weight aqueous second chloride solution for 6 hours to obtain iron chloride. The components were adsorbed. This was set in a closed container filled with pyrrole vapor and left for 24 hours to carry out a polymerization reaction. After the reaction, the product was thoroughly washed with pure water and ethanol, and then dried at 100 ° C.

Next, the above fibers are processed into a plain weave sheet,
Further, a high-pressure water stream was jetted to open the split fibers. After the fiber opening, a raising process was performed using sandpaper and a rigid brush. The resistance of the raised fiber sheet was 1 × 10 ⁸ Ω.

The raised fiber sheet was made of EPDM foam (average foam cell diameter 100 μm) in which conductive carbon black was dispersed.
m, outer diameter 12 mm, cored bar 6 mm), and a charging roller was produced.

(Embodiment 6) Conductive acrylic fibers in which conductive carbon black is dispersed (single fiber, fiber diameter 20 μm,
A plain woven sheet was prepared by plain weaving (1 × 10 ⁴ Ω) so that the horizontal lines were in contact with each other. Further, after brushing with sandpaper, brushing was performed to arrange the coat.

A charging roller was produced in the same manner as in Example 1 except that the obtained raised fiber sheet was used.

(Comparative Example 1) A charging roller was produced in the same manner as in Example 1 except that the fiber sheet was made conductive in the unopened and unbrushed state.

(Comparative Example 2) The fiber sheet of Example 3 was attached to a blade-shaped stainless steel substrate (the same product as in Example 4) in the unopened and unbrushed state to prepare a charging blade.

Comparative Example 3 The split fiber of Example 3 was 0.4.
It was cut into mm and the sea part was hydrolyzed with an aqueous sodium hydroxide solution. 30 parts by weight of the obtained ultrafine fibers were mixed and dispersed in a urethane resin together with 30 parts by weight of conductive tin oxide. This was dip-coated on an EPDM foam similar to that used in Example 5 to form a surface layer having a thickness of 100 μm.

(Evaluation) The charging roller was attached to the electrophotographic apparatus (laser printer) shown in FIG.
To contact the photoreceptor. The photoconductor used was one having no charge injection layer but a charge transport layer as a surface layer.

The electrophotographic device (laser printer) is
Process speed 16 sheets / min, resolution 600d
It was set to pi, and a predetermined voltage was applied to the charging roller rotating at an opposing peripheral speed difference of −150% with respect to the rotation of the photoconductor, and the surface abrasion of the photoconductor and the image quality were investigated.

The charging blade was attached to the photosensitive member in a fixed state by being attached to a protective jig which is an improved contact charging device dedicated to the roller.

The image output environment is high temperature and high humidity H / H (32.5
C., 85%), normal temperature and normal humidity N / N (23.degree. C., 60%), and low temperature low humidity L / L (15.degree. C., 10%).

The applied voltage is AC 1.8 kVpp + DC-7.
00V and DC-1200V.

The number of durable sheets was set to 20,000.

For image evaluation, a reflectometer (TC-6DS manufactured by Tokyo Denshoku Co., Ltd.) was used to measure the whiteness of the white portion of the transfer paper after printing and the whiteness of the transfer paper before printing, and the difference between the two was measured. Fog (%) was calculated from the above. If the fog is 5% or more, the image quality becomes a problem.

The evaluation items are the following three items. 1) As the fog caused by the charging member, the image fog evaluation was performed when the image of the initial image fog and the durable charging member were subjected to image formation with a non-durable photoreceptor. 2) Image fog evaluation by a durable photosensitive drum as fog caused by drum abrasion. 3) Image fog evaluation by DC charging.

The image quality was evaluated on a 4-point scale with a fog of 5% as a boundary (Table 1).

[0102]

[Table 1]

(Evaluation Results) Table 2 shows the evaluation results of Examples and Comparative Examples.

The charging member of the present invention did not generate image fog due to surface abrasion and exhibited uniform chargeability, and no deterioration in image quality due to fog was observed even after running.

Also in the case of DC charging, the charging property was good and the fog was 5% or less.

On the other hand, the unentangled fiber entangled body could not prevent the photoconductor from being scraped, and the image fog was conspicuous because sufficient chargeability could not be obtained.

Even when the ultrafine fibers were dispersed in the resin, the charging property was low, and the charging failure was caused by the abrasion of the photoconductor.

[0108]

[Table 2]

(Photoreceptor Production Example 1) Five functional layers are provided on an aluminum cylinder having a diameter of 30 mm.

The first layer is a conductive layer, which is provided for smoothing defects in the aluminum drum and for preventing moire due to reflection of laser exposure and having a thickness of about 20 μm. Is.

The second layer is a positive charge injection preventing layer (undercoat layer), which plays a role of preventing the positive charges injected from the aluminum support from canceling out the negative charges charged on the surface of the photoconductor, and the amylan. It is a medium resistance layer having a thickness of about 1 μm whose resistance is adjusted to about 10 ⁶ Ωcm by a resin and methoxymethylated nylon.

The third layer is a charge generation layer, which is a layer having a thickness of about 0.3 μm in which a disazo pigment is dispersed in a resin, and positive and negative charge pairs are generated by laser exposure.

The fourth layer is a charge transport layer, which is a polycarbonate resin in which hydrazone is dispersed, and has a thickness of 20.
It is a P-type semiconductor of μm. Therefore, the negative charges charged on the photoreceptor surface cannot move through this layer, and only the positive charges generated in the charge generation layer can be transported to the photoreceptor surface.

The fifth layer is a charge injection layer and is a layer having a thickness of 3 μm in which SnO ₂ ultrafine particles are dispersed in a photocurable acrylic resin. Specifically, 65 wt% of SnO ₂ particles having a particle size of about 0.03 μm, which is doped with antimony to reduce resistance, further 30 wt% of tetrafluoroethylene resin particles, 0.2% by weight dispersed.

As a result, the volume resistance value on the surface of the photoconductor was lowered to 7 × 10 ¹² Ωcm, compared with 3 × 10 ¹⁵ Ωcm in the case of the charge transport layer alone.

(Photoreceptor Production Example 2) Mirror-finished φ3
A blocking layer, a photoconductive layer, and a surface layer (charge injection layer) were sequentially formed on a 0 mm aluminum cylinder by the glow discharge method.

First, after the reaction chamber was set to about 7.5 × 10 ⁻³ Pa, the temperature was kept at 250 ° C. in an aluminum cylinder while SiH.
₄ , B ₂ H ₆ , NO, and H ₂ gas were fed into the reaction chamber, while the gas was discharged from the reaction chamber to an internal pressure of about 30 Pa, and then glow discharge was generated to form a 5 μm-thick prevention layer. .

[0118] Then, using the same method as the formation of the barrier layer, using SiH ₄ and H ₂ gas, after the internal pressure of 50 pa, to form a photoconductive layer having a thickness of 20 [mu] m, further, S
A surface layer made of Si and C having a thickness of 0.5 μm was formed by glow discharge under a pressure of 55 Pa using iH ₄ , CH ₄ and H ₂ gas to prepare an amorphous silicon photoconductor.

Examples 7 to 14 Using the photoconductors obtained in the photoconductor production examples 1 and 2 (hereinafter referred to as photoconductors 1 and 2), the charging members obtained in Examples 1 to 6 (hereinafter, The charging members 1 to 6) were evaluated.

An electrophotographic apparatus having the same structure as that used in Examples 1 to 6 was used, but the applied voltage was set to DC-750V in Examples 7 to 10, and Example 1 was used.
In 1-14, it was set to + 500V.

The evaluation was carried out by evaluating the charging efficiency in the initial stage and the image fog after the durability test of 20,000 sheets.

The charging efficiency is represented by (charging potential of photosensitive member / applied voltage) × 100 (%), and 90% or more is good charging property, and 95% or more is excellent charging property. The evaluation standard of fog conforms to Table 1. Environmental conditions are L / L (1
5 ° C., 10%). Table 3 shows the results.

Comparative Examples 4 and 5 The charging members were evaluated in the same manner as in Example 7 except that the charging members obtained in Comparative Examples 1 and 2 (hereinafter referred to as comparative charging members 1 and 2) were used. Table 3 shows the results.

[0124]

[Table 3]

[0125]

As described above, according to the present invention, the contact property with respect to the member to be charged is excellent, the surface of the member to be charged is not easily scraped,
It is possible to uniformly charge an object to be charged even after repeated use, and to provide a charging member suitable for injection charging, a process cartridge having the charging member, and an electrophotographic apparatus.

[Brief description of the drawings]

FIG. 1 is a sectional view of a charging roller of the present invention.

FIG. 2 is a sectional view of a charging roller having a conductive elastic layer of the present invention.

FIG. 3 is a front view and a side view of a charging blade of the present invention.

FIG. 4 is a sectional view of the charging belt of the present invention.

FIG. 5 is a sectional view of a conventional charging roller.

FIG. 6 is a front view of the contact charging device.

FIG. 7 is a configuration diagram of a main part of a laser beam printer having a process cartridge having a contact charging member.

DESCRIPTION OF SYMBOLS 1 Contact charging roller of the present invention 2 Conductive substrate (core metal) 3 Charging layer (raised fiber entanglement) 4 Conductive charging layer 10 Conventional charging roller 11 Conductive substrate (core metal) 12 Charging Layer 13 Conductive Elastic Layer 20 Contact Charging Device 21 Photoreceptor (Photosensitive Drum) 22 Pressurizing Spring 23 Power Supply 31 Laser Light 32 Developing Device 33 Transfer Device 34 Transfer Material 35 Cleaning Device 36 Fixing Device 37 Process Cartridge 38 Rail

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshifumi Hino 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (11)

[Claims] 1. A charging member, which is placed in contact with a body to be charged and charges the body to be charged by applying a voltage, comprising a conductive substrate and a surface layer in contact with the body to be charged, A charging member comprising a fiber entangled body whose layers are raised. 2. The charging member according to claim 1, wherein the fiber entangled body has at least one of an etching fiber and a split fiber. 3. The charging member according to claim 2, wherein the fiber entangled body has etching fibers. 4. The fiber entanglement has split fibers.
The charging member as described in the above. 5. The average diameter of the fibers of the fiber entangled body is 0.
The charging member according to claim 1, wherein the charging member has a thickness of from 05 μm to 30 μm. 6. The charging member according to claim 1, wherein the member to be charged is an electrophotographic photosensitive member. 7. The charging member according to claim 6, wherein the electrophotographic photosensitive member has a charge injection layer. 8. An electrophotographic photosensitive member and the charging member according to claim 1, or an electrophotographic photosensitive member, the charging member according to claim 1 and at least one of a developing unit and a cleaning unit. A process cartridge, which integrally supports the means and is detachable from the apparatus main body. 9. The process cartridge according to claim 8, wherein the electrophotographic photosensitive member has a charge injection layer. 10. An electrophotographic apparatus comprising an electrophotographic photosensitive member, the charging member according to claim 1, an exposing unit, a developing unit, and a transferring unit. 11. The electrophotographic apparatus according to claim 10, wherein the electrophotographic photosensitive member has a charge injection layer.