JPH07128951A - Electrostatic charge device - Google Patents

Abstract

PURPOSE:To provide a high reliable electrostatic charge device constituted so that brush mark-like stripe-state image noise is improved, an excellent image can be obtained, electrostatic charge performance is not deteriorated and the brush mark-like stripe-state image noise is prevented from being remarkably caused when the device is used for a long term. CONSTITUTION:The electrostatic charge device 2 for electrostatically charging the surface of a body to be electrostatically charged 1 is provided with plural contacts arranged so that they can be moved to a contact position where they rub the surface of the body 1 and a non-contact position, a regulation means which is arranged by abutting on the contacts and which regulates the moving state of the contacts to the non-contact position from the contact position and a means impressing an electrostatic charge voltage between the contacts and the body 1 in order to electrostatically charge the surface of the body 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic copying machine,
The present invention relates to a charging device for an image forming apparatus such as a printer or a facsimile.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic copying machine, a printer or a facsimile, an electrostatic latent image carrier such as a photosensitive drum is charged by a charging device, and the charged area is imagewise exposed to electrostatic charge. A latent image is formed, the latent image is developed into a visible image, which is transferred to a transfer material and fixed.

Various types of charging devices are known as the above-mentioned charging device. When roughly classified, a corona charging device utilizing corona discharge by a corotron system, a scorotron system, a sawtooth electrode array system, a brush, a roller, It is classified into a contact type charging device in which a charging member having a shape such as a film or a belt is brought into contact with the surface of the electrostatic latent image carrier.

The charging device using corona discharge has an advantage that stable charging can be performed, but there is a problem that a large amount of ozone is generated, which causes deterioration of the electrostatic latent image bearing member and adversely affects the human body. Therefore, a contact charging device, which generates much less ozone than a corona charging device, is attracting attention. Among them, a contact charging device having a plurality of contacts, such as a contact charging device having a brush shape or a contact charging device having a plurality of films, is inexpensive and excellent in electrostatic latent image carrier. It is a charging method that can easily maintain proper contact.

However, in such an electric contact device composed of a plurality of contacts, so-called brush streak-shaped image noise is remarkably generated because the contacts contact the surface to be charged unevenly.
Therefore, although the image output device that handles only the binary image in which the streak-like image noise is less noticeable has been put into practical use, it has not been put into practical use in the device that requires halftone image output, and is expensive instead. A roller-shaped charging device has been put into practical use.

For example, Japanese Patent Laid-Open No. 58-40566 discloses a plate member for applying a potential to the surface of a rotary brush, and Japanese Patent Laid-Open No. 58-199365 discloses a structure in which a rotary brush is housed in a casing. No. 60-130767 discloses a configuration in which a rotating magnetic brush is raised by an arc-shaped magnet, and No. 60-168148 discloses a configuration in which a brush roller is cleaned by a flicker bar.
No. 7 discloses a structure in which fibers are coated with silicone resin, JP-A-59-224871 discloses a structure in which fibers at a contact portion of a photoconductor are treated with insulation, and JP-A-60-160907 discloses carbon. A configuration in which the fiber is coated with a conductive resin and a configuration in which the brush tip is coated with a conductive elastic member are disclosed in Japanese Patent Laid-Open No. Sho 62-235968, but in both cases, the contactor is on the surface to be charged. Due to non-uniform contact, so-called brush streak image noise is remarkably generated, and it has not been used in a device that requires halftone image output.

[0007]

SUMMARY OF THE INVENTION In a conventional charging device composed of a plurality of contact elements, since the contact elements contact the surface to be charged unevenly, brush streak-shaped image noise is remarkably generated, and halftone image output is performed. It could not be applied to the equipment that requires Further, when used for a long period of time, stains such as toner and paper dust adhere to the surface of the contactor through the electrostatic latent image carrier, which further promotes brush streak image noise. It was

Therefore, according to the present invention, it is possible to obtain a good image by improving the streak-like image noise of the brush as compared with the conventional charging device having a plurality of contacts, and the charging performance is not impaired. An object of the present invention is to provide a highly reliable charging device capable of preventing the striation image noise from becoming remarkable.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted extensive research to solve the above-mentioned problems, and as a result, in a charging device having a plurality of contacts, a contact member of a portion that contributes to discharge is controlled by a regulating member. The present invention has been completed by finding that the generation of the brush streak-shaped image noise can be solved by aligning and sending the aligned state to the non-discharge area.

That is, according to the present invention, in a charging device for charging the surface of a body to be charged, a plurality of contacts arranged movably between a contact position and a non-contact position where the surface of the body to be charged is rubbed. And a restricting unit that is disposed in contact with the contactor and restricts a moving state of the contactor from a contact position to a non-contact position, and the contactor and the contactor for charging the surface of the charged body. The present invention relates to a charging device including means for applying a charging voltage between charged bodies.

More specifically, the restricting member of the present invention is
Before the deformation of the plurality of contacts rubbed against the body to be charged is restored after the rub, the contacts are regulated by contacting the plurality of contacts.

That is, in the conventional charging device having the contactor, when the contactor slides into contact with the body to be charged and then moves to the non-contact position, the contactor moves away in a repulsive behavior. At this popping stage, the contact is in non-contact with the body to be charged, but at the beginning of the popping, the contactor and the body to be charged are kept very close to each other, so the Paschen's law is established and the contact The discharge is sustained unless the child jumps to an area where the Paschen's law does not hold. At this time, in the conventional charging device, the contacts randomly fly off, and charging is performed at the jumped position. Since there is a low probability that other contacts will be present around the popped contact, only the popped contact will continue to discharge preferentially, preventing uniform charging and causing streak-like noise. Will be observed.

In the present invention, since the regulating member for contacting the contactor to regulate the sliding condition of the contactor is provided, when the contactor is slidably contacted with the member to be charged and then separated, the contactor is regulated by the regulating member. It is regulated and uniform charging can be achieved.

Further, in the present invention, it is preferable that the angle θ formed by the contactor and the surface of the member to be charged is regulated to be 50 degrees or less.

That is, when the contactor is in contact with the member to be charged in a state where the contact angle is large and the contactor is standing, the contactor slides and moves,
The distance relationship between the body to be charged and the contact changes abruptly.
For this reason, the number of contacts at positions that satisfy the Paschen's law among the plurality of contacts is reduced stochastically, and the tendency that charging becomes uneven becomes stronger. Therefore, it is preferable that the angle θ is laid down so as to stochastically increase the number of contacts at positions that satisfy the Paschen's law among the plurality of contacts, and for this purpose, it is preferable that the angle θ is 50 degrees or less. .

Further, according to the knowledge of the present inventors, in a charging device having a contact, the discharge spreads like a spindle from the tip of the contact. Therefore, uniform charging may be hindered between a portion where the spindle-shaped spreads overlap and a portion where the spindle-shaped spreads do not overlap, and this may be observed as a streak-like noise. In order to prevent this, it is preferable to reduce the charge transport performance of the contact to some extent, specifically, to provide a high resistance surface coating layer. On the other hand, from the viewpoint of the efficiency of the charging potential with respect to the applied voltage, it is preferable that the conductivity of the contactor is secured high. In order to prevent such spindle-shaped discharge from the tip of the contact and to satisfy both charging efficiency, it is preferable that the electric resistance of the surface coating layer be higher than that of the inside of the contact. Specifically, the electrical resistivity of the surface coating layer is 1
0 ⁶ to 10 ¹¹ Ωcm, and the internal electrical resistivity is 10 ⁶ Ωc
It is preferably m or less.

Further, in the present invention, it is preferable to apply a voltage to the regulating member. In that case, it is preferable that the voltage applied to the regulating member has the same polarity as the charging voltage of the charging device.

That is, impurities having a polarity opposite to that of the applied voltage, such as toner or paper powder, are easily attached to the contacts of the charging device and easily contaminated. In order to remove this dirt from the contactor, it is preferable that the dirt is adsorbed, that is, the same polarity as the charging voltage of the charging device. Further, in order to positively remove the dirt from the contact, it is preferable to set the absolute value of the voltage applied to the regulating member to be larger than the absolute value of the charging voltage of the charging device, and to apply a high voltage.

When the contactor is a brush in the present invention, it is preferable to implant or attach the brush contactor to the conductive support.

As such a conductive support, iron, S
A metal material such as US, aluminum, copper, chromium, titanium, or the like, or a resin material and a fiber material that have been subjected to a conductive treatment can be used.

Further, various conductive fiber materials can be used for the brush. Such brush fiber materials include metal wires such as stainless steel, tungsten, gold, platinum, aluminum, iron, copper, and the like as metal fiber materials.
It can be used while appropriately adjusting its length or wire diameter. Further, as the conductive resin fiber material, rayon,
Nylon, acetate, cuprammonium, vinylidene, vinylon, ethylene fluoride, promix, benzoate,
Resistance modifiers such as carbon black, carbon fibers, metal powder, metal whiskers, metal oxides, semiconductor materials, etc. are dispersed in fibers such as polyurethane, polyester, polyethylene, polyvinyl chloride, polyclar, polynosic, polypropylene, etc. You can use things. In this case, a desired resistance value can be appropriately obtained depending on the amount of dispersion. Further, instead of dispersion, a material in which the resistance adjusting material is coated on the fiber surface may be used as the brush fiber material.

Here, the cross-sectional shape of the brush fiber material is circular, elliptical, circular with a wrinkle-like periphery, polygonal, flat, or having a cavity inside, as long as the chargeability is not impaired. For example, a shape that is easy to make due to the manufacturing method may be appropriately selected. Further, the fiber diameter is not particularly limited as long as it can ensure the adhesion with the electrostatic latent image bearing member, and the brush fiber strength is within a range that does not cause a problem in practical handling and durability. Generally, about 5 to 500 μm can be considered.

On the other hand, when the contact is formed of a film in the present invention, it is preferable to implant or adhere the film contact to the conductive support.

As such a conductive support, the same material as the conductive support in the brush-type charging device can be used.

The material for the film contactor is polyethylene, polypropylene, ionomer, polyvinyl alcohol, polyvinyl acetate, ethylene vinyl acetate copolymer, poly-4-methylpentene-1, polymethylmethacrylate, polycarbonate, polystyrene. , Acrylonitrile methyl acrylate copolymer, acrylonitrile butadiene styrene copolymer, ethylene polyterephthalate, polyurethane elastomer, cellulose nitrate, cellulose acetate, cellulose triacetate, cellulose propionate, cellulose acetate butyrate, ethyl cellulose, regenerated cellulose, nylon 6, Nylon 66, Nylon 11, Nylon 12, Polyimide, Polysulfone, Polyethersulfone, Polyvinyl chloride, Vinyl chloride vinyl acetate copolymer, Polyvinyl chloride Powdered in plastic film materials such as lidene, vinylidene chloride vinyl chloride copolymer, vinyl nitrile rubber alloy, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polyethylene tetrafluoroethylene copolymer, etc. Body shape, fiber shape, conductive carbon, iron, etc.
Aluminum, copper, chrome, titanium, tin, zinc, gold,
Metals such as silver, cobalt, lead, platinum, antimony oxide,
It is possible to use a film in which a metal oxide such as indium oxide or molybdenum oxide, a conductive polymer such as polyacetylene, polypyrrole, polythiophene, or the like is dispersed and conductive treatment is performed. Further, instead of dispersion, a film surface coated with a resistance adjusting material may be used as the film material. Here, the film material may be composed of two or more kinds of materials, or may be composed of two or more layers. Further, such a film can be produced by appropriately using a usual method of film molding such as a casting method, an extrusion method, a stretching method and the like.

Here, the surface shape of the film material may be smooth, but as long as the charging property is not impaired, the film material has an appropriate surface roughness in order to meet the requirements from the ease of manufacturing in the manufacturing method. It may be, and generally, it may be within 100 μm. Further, the thickness is not particularly limited as long as the adhesion with the electrostatic latent image bearing member can be secured, and the film strength is within a range that does not matter in terms of practical handling and durability, From about 5 to 500 μm is possible.

Regardless of the brush form or film form, when providing a surface coating layer on these contacts, conductive carbon such as powder form, fiber form, iron, aluminum,
Copper, chromium, titanium, tin, zinc, gold, silver, cobalt,
Metals such as lead and platinum, metal oxides such as antimony oxide, indium oxide and molybdenum oxide, conductive polymers such as polyacetylene, polypyrrole, polythiophene, etc. dispersed, petroleum-based, aromatic-based, alcohol-based , Ester-based, ketone-based, cellosolve-based, water-based paints,
The surface can be coated by appropriately adopting a coating method such as a dipping method, a spray method, a bar coating method, a curtain flow method, an electrodeposition coating method and a roll coating method. Further, using a metal or metal oxide as described above, or a gas such as a silicon compound, a boron compound, a phosphorus compound, a hydrocarbon compound, or an organic metal as a raw material, vacuum deposition, sputtering, ion plating, photo CVD, Surface coating can be performed by appropriately adopting a conventional vacuum thin film forming method such as thermal CDV or plasma CVD.

Further, in the wet spinning method generally used for producing a fiber material and the extrusion molding method which is one of the film forming methods, materials having different properties can be easily laminated by multiplexing or multilayering the die. It is particularly preferable as the surface coating treatment method because it is possible.

Here, the film thickness of the surface coating layer is not particularly limited as long as the adhesiveness with the brush fiber material or the film material is not impaired and a desired resistance value can be given to the surface coating layer. No, but generally 1-500 μm
It should be about. For the purpose of ensuring the adhesiveness when the surface coating layer is provided on the brush fiber material or film material, apply the silane coupling agent or the primer layer on the surface of the brush fiber material or the film material before providing the surface coating layer. Alternatively, acid treatment, alkali treatment, plasma treatment, or the like may be performed.

In the charging device of the present invention thus manufactured, a charging voltage is applied through the above-mentioned conductive support or the like, and the applied voltage at that time is DC or A to DC.
A voltage with C superimposed can be used. Where D
It is preferable to use a voltage value of approximately 800 to 1500 V as the C voltage. For example, when superimposing an AC component on this DC component for the purpose of preventing a change in charging potential due to environmental changes, a peak-to-peak voltage of 400 to 2000 V is applied. It suffices to superimpose a certain AC component at a frequency of 0.2 to 5 kHz. Further, this AC component does not have to be a sine wave, and for example, for the purpose of reducing the power supply cost, a pulsating flow of a rectangular wave such that two predetermined voltage values are alternately switched at a predetermined duty ratio may be used.

In the present invention, the term "charging device" is used in the electrophotographic system to form a charged area for forming an electrostatic latent image on an electrostatic latent image carrier such as a photoconductor by performing image exposure. It is not limited to the charging device. For example, when the electrostatic latent image is developed with toner and then the toner image is transferred to a transfer material,
A charging device for transferring a charge having a polarity opposite to that of the toner from the back surface of the transfer material, or a charge having a predetermined polarity in order to eliminate residual charge remaining on the electrostatic latent image carrier after the transfer. In order to remove the charge held on the charging device for removing the static electricity applied to the electrostatic latent image carrier or the fixing member that fixes the toner image transferred to the transfer material by heat or pressure, the charge of a predetermined polarity is fixed. It also means a charging device for giving a charge on a member or a charging device for giving a charge of a predetermined polarity to the toner or the developer in order to charge the one-component toner or the two-component developer in the developing device to the predetermined polarity.

[0032]

Embodiments of the present invention will be described below with reference to the drawings.

Each of the embodiments described below is used by being incorporated in a copying machine whose main part is shown in FIG. First, a copier whose main part is shown in FIG. 1 will be described.

The copying machine, the main part of which is shown in FIG. 1, is provided with a photosensitive drum 1 which is an electrostatic latent image carrier at the center thereof, and this drum is rotationally driven counterclockwise in the drawing by a driving means (not shown). It Around the photosensitive drum, the charging device 2,
Developing device 3, transfer charger 4, cleaning device 5
And the eraser 6 are sequentially arranged. The charging device 2 is a charging device having a brush form or a charging device having a plurality of film forms according to the present invention. It

An optical system (not shown) is arranged above the photosensitive drum 1, and this optical system is a well-known system including an exposure lamp, a reflection mirror, an optical lens, a slit and the like. With this optical system, image exposure can be performed on the photosensitive drum 1 from the position L shown in FIG.

An intermediate roller pair 7 and a timing roller pair 8 are sequentially arranged on the left side of the photosensitive drum 1 in the figure,
Transfer paper stored in a paper feed cassette (not shown) is supplied from position C shown in FIG.

According to this copying machine, the surface of the photosensitive drum 1 is uniformly charged to a predetermined potential by the charging device 2, and the charged area is imagewise exposed from the position L by the optical system to form an electrostatic latent image. . The electrostatic latent image thus formed is the developing device 3
Is developed into a toner image and transferred to the transfer charger 4
Transfer to the transfer area.

On the other hand, the transfer paper supplied from the position C reaches the timing roller 8 via the intermediate roller pair 7 and is sent to the transfer area in synchronism with the toner image on the photosensitive drum 1. Thus, in the transfer area, the toner image on the photosensitive drum 1 is transferred onto the transfer paper by the action of the transfer charger 4, and the transfer paper is moved to the position F by the conveyor belt 9.
The toner image is conveyed by the fixing device (not shown), and then the sheet is ejected.

After the toner image is transferred onto the transfer paper, the toner remaining on the photosensitive drum 1 is cleaned by the cleaning device 5, and the residual charge is erased by the eraser 6.

The system speed of this copying machine (peripheral speed of the photosensitive drum 1) is made variable in the range of 10 to 40 cm / sec by selecting a driving means (not shown).
Is a two-component regular developing device.

The photoconductor drum 1 is a function-separated type organic photoconductor for negative charging, which has a good sensitivity in the relative luminous efficiency region. The method for producing the function-separated type organic photoreceptor will be described below.

First, the following structural formula:

[0043]

[Chemical 1]

0.45 parts by weight of the azo compound represented by the formula: polyester resin (Vylon 200: manufactured by Toyobo Co., Ltd.)
45 parts by weight and 50 parts by weight of cyclohexanone were placed in a sand grinder and dispersed for 24 hours to obtain a photosensitive coating liquid. At this time, the viscosity of the photosensitive coating liquid was 20 cp at 20 ° C. This coating liquid was applied by a dipping method to the surface of an aluminum cylindrical substrate whose surface was cut with a bite to form a charge generation layer having a thickness of 0.3 μm after drying. The cylindrical substrate used here was an aluminum alloy containing 0.7% by weight of magnesium and 0.4% by weight of silicon, and the drying condition was 30 minutes in circulating air at 20 ° C.

Next, on the charge generation layer, the following structural formula:

[0046]

[Chemical 2]

A coating liquid prepared by dissolving 10 parts by weight of the styryl compound represented by and 7 parts by weight of a polycarbonate resin (Panlite K-1300: manufactured by Teijin Chemicals Ltd.) in a solvent consisting of 40 parts by weight of 1,4-dioxane. It was applied by a dipping method and dried to form a charge transport layer having a thickness of 32 μm. The viscosity of the coating liquid at this time was 240 cp at 20 ° C., and the drying condition was 30 minutes in circulating air at 100 ° C.

As described above, the function-separated type organic photoconductor in which the charge generation layer and the charge transport layer were sequentially laminated on the conductive substrate was prepared and used as the photoconductor drum 1.

The photoconductor used in the examples of the present invention is the function-separated type organic photoconductor as described above, but the photoconductor to which the present invention can be applied is not limited to this.

As for the sensitivity range of the photoconductor, a semiconductor laser (780 nm) optical system and an LED array (680 n) are used.
m) In an image forming system using long-wavelength light such as an optical system, a photoreceptor having sensitivity in a long-wavelength region may be used. For example, a visible light source may be used as a light source with a liquid crystal shutter array, a PLZT shutter array, or the like. Image forming system, an image forming system using a visible light laser as a light source, an image forming system using a phosphor light emitting array as a light source, or visible light and a lens commonly used in a general copying machine as described above. In the analog image forming system using the mirror optical system, the photoconductor having the sensitivity in the visible range as described above may be used.

As for the constitution of the photoconductor, the photoconductor is a function-separated type organic photoconductor in which a charge transport layer is provided separately on the charge generation layer. It may be a so-called anti-stack type photoreceptor provided with,
It may be a so-called single-layer type photoreceptor having both a charge generating function and a charge transporting function. Further, as the charge generating material, the charge transporting material, the binder resin, the additive and the like, known materials may be appropriately selected according to the purpose. Also, the photosensitive material is not limited to organic materials, but zinc oxide, cadmium sulfide,
Inorganic materials such as selenium-based alloys, amorphous silicon-based alloys, and amorphous germanium-based alloys may be used.

The photoreceptor applicable to the present invention may further be provided with a surface protective layer in order to improve durability, environment resistance and the like, and may have charging performance, image quality, adhesiveness and the like. An undercoat layer may be provided for improvement. As a material for such a surface protective layer or an undercoat layer,
A resin such as an ultraviolet curable resin, a room temperature curable resin or a thermosetting resin, a mixed resin in which a resistance adjusting material is dispersed in the resin,
Uses vacuum thin film materials made by thinning metal oxides, metal sulfides, etc. in vacuum by vapor deposition or ion plating, amorphous carbon film produced by plasma polymerization method, amorphous silicon carbide film, etc. You can do it.

The substrate material of the photoreceptor applicable to the present invention is
The support is not particularly limited as long as it has a conductive surface, and may have a flat plate shape or a belt shape other than the cylindrical shape. Further, the surface of the substrate may be roughened, oxidized, or colored.

The toner used in the developing device 3 is a positive charging type indefinite styrene acrylic toner. The method for producing the toner will be described below.

First, styrene-n-butyl methacrylate resin (softening point: 132 ° C., glass transition temperature: 60 ° C.)
Carbon black (Mogul-
L: Cabot Co., Ltd.) 8 parts by weight, Nigrosine dye (Bontron N-01: Orient Chemical Co., Ltd.) 5 parts by weight and non-polar polypropylene (605P: Sanyo Kasei Co., Ltd.) 3 parts by weight, and a ball mill is sufficient. Mixed. Next, this mixture was sufficiently kneaded on a three-roll roller heated at 140 ° C., the kneaded product was left to cool, coarsely pulverized, and then finely pulverized by a jet mill. This finely pulverized product was subjected to air classification to obtain a toner of a positive charge type indefinite shape having an average particle size of 7.5 μm. When used in the examples of the present invention, 100 parts by weight of the toner was used for the purpose of imparting fluidity. Hydrophobic silica (R-9
74: manufactured by Nippon Aerosil Co., Ltd.) 0.2 parts by weight was used for post-treatment with a Henschel mixer.

The above toner was mixed with carrier particles, charged into the developing device 3 and used as a developer. The method for producing the carrier will be described below.

First, polyester resin (Tufton NE1
110: 100 parts by weight of Kao Co., 2 parts by weight of carbon black (MA # 8: Mitsubishi Kasei Co., Ltd.) and 300 parts by weight of magnetic powder (MFP-2: TDK Co., Ltd.) were added to 100 parts by weight of Henschel. Mix well with a mixer. The obtained mixture was sufficiently kneaded with a twin-screw extruder, cooled, and coarsely pulverized.
The coarsely pulverized product was finely pulverized and classified by a jet mill pulverizer and an air classifier to obtain magnetic powder-containing polymer fine particles having an average particle diameter of 2 μm.

Then, ferrite particles F-250HR
(Average particle size of 50 μm: manufactured by Powder Tech Co., Ltd.) To 100 parts by weight of the magnetic powder-containing polymer fine particles, 10 parts by weight of the polymer powder was added, and the mixture was treated with Ongmill AM-20F (manufactured by Hosokawa Micron Co., Ltd.) at a rotation speed of 2500 rpm for 40 minutes, and then averaged. A carrier intermediate having a particle size of 55 μm was obtained. Further, the carrier intermediate was heat-treated at 400 ° C. using a suffusing system (manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to obtain a carrier having an average particle diameter of 55 μm.

The above toner and carrier are mixed and stirred so that the toner concentration becomes 7% by weight, and then charged into the developing device 3,
An unillustrated toner concentration detector and toner replenishing device were used for image formation while always maintaining the toner concentration at 7 ± 1% by weight.

In the embodiment of the present invention, the positive charge type indeterminate black toner and the above carrier were used as the developer.
The developer applicable to the present invention is not limited to this.

Negatively charged toner, translucent toner, magnetic toner, iron powder carrier, binder carrier, resin coated carrier, one-component developing system, reversal developing system, depending on the polarity of the photoreceptor and the image forming process used. , Etc. can be appropriately selected and used.

Regarding the color of the toner, not only black toner but also color toners such as yellow, magenta and cyan can be appropriately selected and used, and the toner shape may be an irregular shape or a specific shape. It is also possible to use the shape of, for example, spherical toner, crystalline toner or the like. Regarding the carrier, it is possible to appropriately select and use a developing system in which the powder is not used as the carrier, and for example, a conductive brush, a conductive roller, or the like is made to have the carrier perform the necessary functions.

Further, for the purpose of improving fluidity and cleaning performance, it is also possible to use a developer mixed with powder or beads such as polyvinylidene fluoride resin, Teflon resin and PMMA resin as a lubricant. .

Next, the basic structure of the charging device 2 in the copying machine will be described with reference to FIGS.

FIG. 2 is a perspective view of the charging device 11 having a brush shape, and has a structure in which a plurality of brush fiber materials 13 are arranged on the surface of the conductive support 12. The conductive support 12 has a diameter of 8 mm and a length of 370 m.
A metal shaft made of SUS303 of m was used, and as the brush fiber material 13, rayon-based and nylon-based fibers whose fiber diameter was set by adjusting the spinneret diameter during spinning were used. Here, the rayon-based fiber has a morphological feature of having minute wrinkles on the surface for the reason of the manufacturing method, and the nylon-based fiber has a surface having a smooth and generally so-called columnar shape for the same reason. A material with characteristics was used.

FIG. 3 shows a perspective view of a ribbon-shaped flocking cloth 21 used to attach the brush fiber material to the conductive support. This flocking cloth 21 is a velvety woven using a so-called W weave, in which a pile 23 made by bundling brush fiber materials in an amount of several tens and several hundreds depending on the fiber strength is woven into a base fabric 22 made of polyester fiber. After that, the base cloth 22 was made to be impregnated with a conductive paint. here,
The width of the flocked cloth 21 is 10 to 50 mm, the finished thickness of the base cloth 22 is 0.5 to 2 mm, and the height of the pile 23 is 5 to 30 m.
m, the average flocking density is 100 to 200,000 / square inch, and it is desirable to appropriately select these conditions according to the fiber material type used.

Charging device 1 having a brush form shown in FIG.
1 was produced by spirally winding the flocked cloth 21 shown in FIG. 3 around the conductive support 12 using a conductive adhesive, cutting the ends after the adhesive was cured.

The brush fiber material 13 was prepared by a wet spinning method which is a conventional method for fiber molding. A conductive agent mainly composed of conductive carbon was appropriately adjusted and mixed at the time of compounding before spinning, and electric resistance after molding was obtained. The rayon-based brush fiber material and the nylon-based brush fiber material were produced so that the ratio was 10 ¹ Ωcm to 10 ⁹ Ωcm.

FIG. 4 is a perspective view of the charging device 31 having a plural film form, and has a structure in which a plurality of film materials 33 are arranged on the surface of the conductive support 32.

As the conductive support 32, a metal shaft similar to that of a charging device having a brush shape was used, and as the film material, nylon-based or polytetrafluoroethylene-based materials were used. Here, the polytetrafluoroethylene-based film has a morphological feature that has minute streaky irregularities on the surface for the reason of the manufacturing method, and the nylon-based film has a smooth surface and a so-called cylindrical shape for the same reason. A material having a morphological characteristic of

FIGS. 5 (a) and 5 (b) are perspective views of the ribbon-shaped film patch 41 used for attaching the film material to the conductive support. This film sticking material 41 was produced by sticking a section 43 of the film material to a base material 42 made of aluminum foil with a conductive adhesive. At this time, the thickness of the base material 42 is 30 to 500 μm.
m, the width of the film patch 41 is 2 to 50 mm, the section 43
Is 5 to 30 mm, and the average attachment interval of the sections 43 is 5 to
The number of sheets is 100 sheets / inch, and it is desirable to appropriately select these conditions according to the type of film material used.

In the charging device 31 having a multi-film form shown in FIG. 4, the film patch 41 shown in FIG. 5 is spirally wound around the conductive support 32 using a conductive adhesive, and after adhesive curing, It was produced by cutting the end portion.

The film material 33 was produced by using a casting method which is a conventional method for film formation. However, a conductive agent mainly containing conductive carbon was appropriately adjusted and mixed at the time of compounding before molding so that the electric resistivity after molding was Nylon-based film materials and polytetrafluoroethylene-based film materials were produced so as to have a resistance of 10 ¹ Ωcm to 10 ⁹ Ωcm.

Incidentally, FIG. 5 (a) is a drawing exemplifying the attachment form of a normal section 43, and FIG. 5 (b) is a drawing exemplifying the attachment form in the case of high density. The feature (b) is that a plurality of adhesive margins at the time of attachment are overlapped.

The charging device 2 manufactured as described above is attached to the copying machine whose main part is shown in FIG.
The positional relationship between the photosensitive drum 1 and the photosensitive drum 1 is shown in FIG. The charging device 2 is arranged so that the outer peripheral line 51 indicated by the chain line formed by the tip of the brush fiber material or the film material intersects with the photosensitive drum 1, and the biting amount X at that time is 1
The condition can be set in the range of 25 mm to 25 mm.

Here, the photosensitive drum 1 was rotated counterclockwise in the figure, and the charging device 2 was also rotated counterclockwise in the figure so as to come into contact with the photosensitive drum 1 at the counter. The regulating member 52 according to the present invention with which the brush fiber material or the film material of the charging device 2 contacts is arranged on the downstream side in the rotation direction of the charging device 2 and is a straight line connecting the center points of the photoconductor drum 1 and the charging device 2. On the other hand, the length Y in which the regulating member 52 bites in the right angle direction can be set within the range of -15 mm to +15 mm. Further, the clearance Z between the bottom surface of the regulation member 52 on the side of the photosensitive drum 1 and the surface of the photosensitive drum 1 is 0 to
The condition can be set within the range of 5 mm.

The plate thickness t of the regulating member 52 is 0.
A plate material of 05 mm to 5 mm can be attached, and a conductive plate material, an insulating plate material, or a semiconductive plate material is appropriately selected as a material, and a bias voltage can be applied to the regulating member 52 from a power supply device (not shown) as necessary. I chose

In the present embodiment, the shape of the fiber tip portion 61 of the brush fiber material 13 is configured to have a substantially circular cross section as shown in FIG. 7A, but the shape is not particularly limited. Due to demands for process compatibility with the electrostatic latent image carrier, developer, etc., ease of processing such as brush fiber molding, brush fiber cutting, etc., a diagonal cut shape as shown in FIG. Alternatively, as shown in (c), the fiber tip portion 61 may have a spherical shape, or as shown in (d), the brush fiber itself may be woven into a loop shape.

Further, in the present embodiment, the shape of the film end portion 71 of the section 43 of the film material is vertically cut as shown in FIG. Consistency in process with electro-latent image carrier, developer, etc., limitation in form during mounting, film molding,
The film may be cut obliquely as shown in (b) of FIG. 8 according to a request for ease of processing such as film cutting and alignment, and prevention of bending peculiar to the film material.
The shape may be zigzag cut as shown in Fig. 4, or the specific portion may be provided with irregularities as shown in (d) or (e), or the tip may be bent into an L shape as shown in (f). The shape may be changed.

According to the same request, the plurality of contacts made of brush fibers or films to be attached do not need to have the same properties, but the shape, resistance value,
A plurality of types of contacts having different bendability, materials, etc. may be regularly or irregularly arranged on the circumference. Further, each contact is not particularly limited in the configuration of one contact according to the same request, and may have a specific resistance value distribution in the contact, or a plurality of materials may be laminated. You may make it the structure which mixed or mixed.

The conductive support 12 does not have to be rod-shaped, and the belt-shaped conductive support 81 shown in the schematic view of FIG. 9 can achieve the object of the present invention. Then, as shown in the schematic view of FIG. 10, a known or easily analogyable deposit removing means 91 such as a flicker bar or a bias electrode is provided in a portion other than the contact portion of the charging device 2 with the photosensitive drum 1. Needless to say, the object of the present invention can be further satisfied.

Further, the regulating member 52 according to the present invention does not have to be provided at one place, and as shown in FIG. 11, the second regulating member 101 is formed so as to face the opposite side of the predetermined position.
May be arranged. That is, the regulating member 52 and the second regulating member 1
Although 01 is a form in which a slit is formed between them, it is desirable that the slit interval S is 0.5 mm to 5 mm. In such a configuration, the charger 2 can be rotated clockwise in the figure, that is, in a follow-up relationship with the photosensitive drum 1.

The various charging devices 2 produced as described above are mounted on a copying machine whose main structure is shown in FIG.
The image quality evaluation body was performed. The evaluation method will be specifically described below.

The charging device 2 is brought into contact with the photosensitive drum 1 at a predetermined biting amount, and a normal rotation peripheral speed of the photosensitive drum 1 of 10 to 40 cm / sec is selected. The applied voltage is selected to be approximately 1 to 5 times (hereinafter, this magnification is referred to as a peripheral speed ratio) with respect to the rotational peripheral speed of the photosensitive drum 1 in the counter direction with respect to the photosensitive drum 1. The surface of the photoconductor was initially charged to -600 V while adjusting in the range of -1.0 to -1.2 kV. At this time, a commercially available surface potential meter (TR
A surface potential meter MODEL 344 manufactured by EK was used.

Then, a half original having a density of 0.4 is placed on the original plate, exposed from the position L in FIG. 1, and developed by the developing device 3, and the obtained toner image is transferred to a transfer paper having a density of 0.03. An image sample for brush-like image noise evaluation was obtained. At this time, the exposure amount was appropriately adjusted so that the maximum image density value in the image density evaluation described below was 1.0.

The image sample obtained was a commercially available image densitometer (Sakura Microdensitometer Mode, manufactured by Konica Corporation).
1PDM-5TypeBR) in a scanning direction of 10 cm in length corresponding to the longitudinal direction of the photoconductor, and a magnification of 50.
Double scanning, a scanning speed of 100 μm / sec, and a measurement area of 50 square μm were used for image density measurement. The image density difference was obtained from the maximum image density (1.0) and the minimum image density measured at this time, and was associated with the sensory evaluation.

Here, it can be said that an image sample having an image density difference of 0.2 or less is an image in which brush-like image noise due to electrification cannot be recognized, and such an image is ranked A. An image sample having an image density difference of more than 0.2 and less than 0.35 is visually insignificant although brush-like image noise due to charging is felt, but it can be said that there is no problem in practical use. It was ranked B. In addition, the image density difference is 0.3
An image sample of more than 5 and less than 0.45 can be said to be an image having no problem in practical use, although brush-like image noise due to electrification can be visually sensed, and such an image was ranked as B '. An image sample with an image density difference of more than 0.45 can be said to be a practically unfavorable image because the brush-like image noise due to charging can be visually recognized at a clear visual distance. It was set to C.

As a first experiment, the effect of the regulating member was verified, and a detailed description will be given below.

First, using a rayon-based brush fiber material having an electric resistivity of 10 ⁵ Ωcm and a fiber diameter of 20 μm,
A charging device 11 having a brush form as shown in FIG. 2 was prepared so that the pile height was 20 mm and the flocking density was 100,000 / square inch. At this time, the width of the blanket is 20 mm
I used the one. Then, in the positional relationship shown in FIG. 6, this charging device has X = 10 mm, Y = 5 mm, Z = 0.
2 mm, while adopting a SUS plate having a plate thickness t = 0.5 mm, the surface of which has been subjected to insulation treatment with a polyimide film attached, as a regulating member, it is attached to a copying machine whose main part is shown in FIG. I went.

As a separate comparative experiment, image evaluation was performed under the same conditions as above except that the regulating member 52 was removed, and the difference in performance from the present invention characterized by providing the regulating member was confirmed. The results are shown in Table 1.

[0091]

[Table 1]

Table 1 shows the results regarding the charging device using the rayon-based brush fiber material. When the image evaluation was attempted also for the charging device using the nylon-based brush fiber material, the listing of the table was omitted, but not at all. Similar results were obtained.

Next, using a nylon film material having an electric resistivity of 10 ⁵ Ωcm and a film thickness of 50 μm, the length of the section 43 is 20 mm, and the average pasting interval of the section 43 is 20 sheets / inch. Then, the charging device 31 having a multi-film form shown in FIG. 4 was manufactured. This time,
The width of the film patch was 10 mm. Then, in the positional relationship shown in FIG.
Mainly shown in FIG. 1 while adopting a SUS plate having a plate thickness of t = 0.5 mm, which has a polyimide film attached and the surface of which has been subjected to insulation treatment so that 10 mm, Y = 5 mm, and Z = 0.2 mm, as a regulating member. The image was evaluated by mounting it on a copying machine showing the part.

As a separate comparative experiment, image evaluation was performed under the same conditions as above except that the regulating member 52 was removed, and the difference in performance from the present invention characterized by providing the regulating member was confirmed. The results are shown in Table 2.

[0095]

[Table 2]

Table 2 shows the results regarding the charging device using the nylon film material. When the image evaluation was attempted for the charging device using the polytetrafluoroethylene film material, the table was omitted, Exactly the same result was obtained.

From the above results, it is understood that the charging device provided with the regulating member according to the present invention can obtain a clearly better image quality than the case where the regulating member is not provided. According to the knowledge of the present inventors, this phenomenon is understood as follows.

That is, in the conventional contact charging device having a plurality of contacts such as a brush and a plurality of films without a regulating member, the contact drum contacts the photoreceptor drum and then the photoreceptor drum behaves like popping. Go away from. In the process of popping, the contact is in non-contact with the photoconductor drum, but when it starts to pop, the Paschen's law is established because it is in a very close position, and the contactor is in a region where the Paschen's law is not established. The discharge by the contact continues until it is fully ejected. Moreover, since each contact element randomly occurs, the probability that another contact element exists around the contact element is extremely low, and one contact element can preferentially continue discharging easily. This causes brush streaky image noise. In addition, since the discharge from the tip of the contact spreads like a spindle, the farther the contact is from the photoconductor drum the wider the discharge width within the range where the Paschen's law holds, and when the photoconductor drum is rotating around the counter. In combination with the peripheral speed, the streak becomes long, and the streak-like image noise of the brush becomes extremely remarkable.

FIG. 12 is an enlarged view of the sliding portion between the charging device 2 and the photosensitive drum 1 in FIG. 6, but in the charging device according to the present invention in which a regulating member is provided in contrast to the conventional type described above, The bounce phenomenon when the contact in the contact state is restored to the non-contact state is the position indicated by a in the figure, that is, at the surface of the regulating member that does not contribute to the charging of the photoreceptor drum and is opposite to the photoreceptor drum. Therefore, it is understood that the occurrence of brush streak-shaped image noise due to the above mechanism can be prevented and an image having no problem in practical use can be obtained.

From the above results and consideration, in the charging device for charging the charged body by giving the potential difference between the charged body and the sliding charge member while rubbing the charging member on the surface of the charged body. The sliding friction charging member is composed of a plurality of rotatably arranged contacts, and the plurality of contacts are rubbed against the body to be charged, and the deformation is restored after the rubbing. It can be understood that the brush streak image noise can be prevented by the charging device in which the contactor is brought into contact with the regulation member.

As a second experiment, the effect exhibited by the inclination of the brush fibers by the regulating member was verified, and a detailed description will be given below.

First, a charging device 2 having a brush form made of the same rayon-based brush fiber material as that used in the first experiment was prepared. Then, in the positional relationship shown in FIG. 6, Z = 10 mm while Z = 10 mm in this charging device.
In the range of 0.2 to 1 mm and t = 0.5 to 1 mm, a SUS plate having a polyimide film attached and the surface of which was subjected to insulation treatment was used as a regulating member, and was attached to a copying machine whose main part is shown in FIG. . At this time, the Y dimension is finely adjusted in the horizontal direction by a micro gauge, and the angle formed by the brush fiber and the photoconductor regulated by the regulation member 52 shown by θ in FIG. I made it a range.
This angle θ was measured and obtained from the front side of the copying machine using a microscope. Table 3 shows the results of the image evaluation thus performed.

The angle θ in each of the experimental examples shown in Tables 1 and 2 is 35 degrees (Table 1 / rayon brush), 40 °
(Table 2 / nylon-based film).

[0104]

[Table 3]

Table 3 shows the results regarding the charging device using the rayon-based brush fiber material. When the image evaluation was attempted also for the charging device using the nylon-based brush fiber material, the listing of the table was omitted, but not at all. Similar results were obtained.

Next, a charging device 2 having a multi-film form made of the same nylon film material as that used in the first experiment was prepared. This charging device is shown in FIG.
In the positional relation shown in, while Z = 10 mm, Z
= 0.2 to 1 mm, t = 0.5 to 1 mm, while using a SUS plate having a polyimide film attached and an insulating surface as a regulating member, it is attached to a copying machine whose main part is shown in FIG. It was

At this time, the Y dimension is appropriately finely adjusted in the horizontal direction by a micro gauge, and the regulating member 5 shown by θ in FIG.
The angle formed by the film material and the surface of the photosensitive drum regulated by 2 was set to be in the range of 25 to 60 degrees while actually measuring with a microscope. Table 4 shows the results of the image evaluation thus performed.

[0108]

[Table 4]

Table 4 shows the results regarding the charging device using the nylon-based film material. When the image evaluation was attempted also for the charging device using the polytetrafluoroethylene-based film material, the listing of the table was omitted. Exactly the same result was obtained.

From the above results, it can be seen that in the charging device in which the regulating member according to the present invention is provided and θ is 50 degrees or less, better image quality can be obtained as compared with the case where θ exceeds 50 degrees. According to the knowledge of the present inventors, this phenomenon is understood as follows. That is, in a contact charging device composed of a plurality of contacts such as a brush and a plurality of films, in a state where θ is large and the contacts stand, the distance relationship between the photoconductor drum and the contacts due to rotation of the photoconductor drum. Changes abruptly, the number of the plurality of contacts that exist at positions that stochastically satisfy the Paschen's rule decreases, and the discharge becomes nonuniform.

On the other hand, in the state where θ is small and the contact is lying, conversely, the number of the plurality of contacts which are stochastically present at the positions satisfying the Paschen's law increase, so that the discharge becomes uniform, It is understood that the generation of brush streak image noise is prevented.

From the above results and consideration, in the charging device for charging the charged body by applying the potential difference between the charged body and the sliding charge member while rubbing the charging member on the surface of the charged body, The rubbing charging member is composed of a plurality of rotatably arranged contacts, and the plurality of contacts are contacted at a stage before the deformation caused by the rubbing of the plurality of contacts on the body to be charged is restored after the rubbing. In the charging device in which the child is brought into contact with the regulating member and the angle θ formed by the contactor portion regulated by the regulating member and the surface of the body to be charged is 50 degrees or less, the streak-shaped image noise Understand that the occurrence can be prevented.

As a third experiment, the effect of providing the surface coating layer on the surface of the contact was verified, and a detailed description will be given below.

First, a rayon-based brush fiber material having an electric resistivity of 10 ⁵ Ωcm and a fiber diameter of 20 μm was used to prepare a brush charging device material with a pile height of 20 mm and a flocking density of 5000 fibers / square inch. It was made. At this time, a flock cloth having a width of 20 mm was used. Subsequently, a conductive fluororubber coating material (mixed coating material of Daiel Latex GLS-213 and GLS-213D manufactured by Daikin) was applied to the surface thereof to prepare a charging device 2 having a brush shape shown in FIG. As a coating method at this time, three steps of dip coating, removal of excess coating solution by centrifugal rotation, and drying at 80 ° C. for 30 minutes are repeated several times, and finally the electric resistivity of the surface layer is 10 ⁸ Ωcm, and after surface coating. The fiber diameter was 100 μm.

In the positional relationship shown in FIG. 6, this charging device has X = 10 mm, Y = 5 mm and Z = 0.2 m.
m, a polyimide film is attached and the surface is insulated, and a SUS plate having a plate thickness t = 0.5 mm is adopted as a regulating member, and is attached to a copying machine whose main part is shown in FIG. I went.

As a separate comparative experiment, image evaluation was performed under the same conditions as above except that the surface coating layer was not provided, and the difference in performance due to the presence or absence of the surface coating layer was confirmed. The results are shown in Table 5.
It was shown to.

The angle θ of each experimental example shown in Table 5 is 35.
It is degree.

[0118]

[Table 5]

Table 5 shows the results regarding the charging device using the rayon-based brush fiber material. When an image evaluation was attempted on the charging device using the nylon-based brush fiber material, the table was omitted, but not at all. Similar results were obtained.

Next, using a nylon film material having an electric resistivity of 10 ⁵ Ωcm and a film thickness of 50 μm,
The length of the section 43 is 20 mm, and the average pasting interval of the section 43 is 1
A film charging device material was prepared so that the number of sheets was 0 / inch. At this time, the width of the film patch was 10 mm. Subsequently, a conductive fluororubber paint (a mixed paint of DAIEL LATEX GLS-213 and GLS-213D manufactured by Daikin Co., Ltd.) was applied to the surface thereof to prepare a charging device 31 having a plural film form shown in FIG. As a coating method at this time, three steps of bar coating, removal of excess coating solution by a spinner, and drying at 80 ° C. for 30 minutes are repeated several times, and finally the electric resistivity of the surface layer is 10 ⁸ Ωc.
m, and the film thickness after surface coating was 130 μm.

In the positional relationship shown in FIG. 6, this charging device has X = 10 mm, Y = 5 mm and Z = 0.2 m.
m, a polyimide film is attached and the surface is insulated, and a SUS plate having a plate thickness t = 0.5 mm is adopted as a regulating member, and is attached to a copying machine whose main part is shown in FIG. I went.

As a separate comparative experiment, image evaluation was performed under the same conditions as above except that the surface coating layer was not provided, and the difference in performance due to the presence or absence of the surface coating layer was confirmed. The results are shown in Table 6.
It was shown to.

The angle θ of each experimental example shown in Table 6 is 40.
It is degree.

[0124]

[Table 6]

Table 6 shows the results regarding the charging device using the nylon film material. When the image evaluation was attempted for the charging device using the polytetrafluoroethylene film material, the table was omitted, Exactly the same result was obtained.

From the above results, it can be seen that in the charging device provided with the surface coating layer according to the present invention, clearly better image quality can be obtained as compared with the case where the surface coating layer is not provided. According to the knowledge of the present inventors, this phenomenon is understood as follows.

Generally, in a contact charging device composed of a plurality of contacts such as a brush and a plurality of films, the discharge at the tip of the contact spreads like a spindle, but even if the bounce phenomenon is suppressed by the regulating member, this phenomenon still remains. Occurs to the extent that it cannot be ignored, and causes slight brush streak-shaped image noise. The spread of the spindle-shaped discharge is caused by the fact that the charge transport performance of the contact is too large, and since the charge replenishment from the contact is sufficient, one contact has a distance relationship with the surface of the charged body. Occurs at all areas where the Paschen's law is satisfied at. By suppressing the spread of this discharge, it is possible to prevent the discharge of neighboring contacts from being disturbed by the preferential wide-range discharge of one contact, and it is possible to achieve a uniform discharge by the contribution of discharge of more contacts.

For that purpose, the charge transport performance of the contact may be lowered, that is, the electrical resistivity of the contact may be increased,
Since the surface coating layer in this experimental example is a material having a higher resistance than the fiber material, it can be understood that the electrical resistivity of the contactor is substantially increased and thus a good image quality is provided.

From the above results and consideration, in the charging device for charging the charged body by applying the potential difference between the charged body and the sliding charge member while sliding the rubbing charging member on the surface of the charged body, A step in which the sliding friction charging member comprises a plurality of contacts having a rotatably arranged surface coating layer, and the deformation when the plurality of contacts rub against the charged body is restored after the sliding. In the above, it can be understood that the generation of brush streak image noise can be more preferably prevented by the charging device characterized by bringing the plurality of contacts into contact with the regulation member.

As a fourth experiment, the relationship between the electrical resistivity of the fiber material and the surface coating material when the surface coating layer was provided on the surface of the contact was verified, and a detailed description will be given below.

First, various fiber materials having different electric resistivities were prepared. Here, since the range of electric resistivity that can be easily manufactured differs depending on the type of fiber material, it is 10 ⁴ to 10 ⁹ in the rayon-based brush fiber material.
In the range of Ωcm, in the case of the nylon brush fiber material, materials having different electric resistivities for each digit were prepared in the range of 10 ¹ to 10 ⁷ Ωcm. As a material with extremely low resistance,
A stainless wire fiber material having an electric resistivity of 10 −4 Ωcm was produced.

The diameter of each of these fiber materials is 20 ±.
5 μm, pile height 20 mm, flock density 500
A brush charging device material was manufactured so that the number of brush charging devices was 0 / square inch. At this time, a flock cloth having a width of 20 mm was used. Then, a conductive fluororubber paint (Daikin Latex GLS-213 and GLS
-213D mixed paint) was applied to prepare a charging device 2 having a brush shape shown in FIG. The coating method at this time includes dip coating, removal of excess coating liquid by centrifugal rotation, and 80 ° C.
The three steps of drying for 30 minutes were repeated a plurality of times to finally make the electric resistivity of the surface layer 10 ² to 10 ¹³ Ωcm and the fiber diameter after surface coating to be 100 μm.

In the positional relationship shown in FIG. 6, this charging device has X = 10 mm, Y = 5 mm, Z = 0.2 m.
m, a polyimide film is attached and the surface is insulated, and a SUS plate having a plate thickness t = 0.5 mm is adopted as a regulating member, and is attached to a copying machine whose main part is shown in FIG. I went.

As another evaluation item, the photosensitive drum is charged while the voltage applied to the charging device 2 is fixed at -1.1 kV, and the developing device 3 of the copying machine, the main part of which is shown in FIG. A surface potential meter was attached at the position instead of the developing device 3, and the charged potential on the surface of the photoconductor was measured without image exposure. The results are shown in Table 7.

In the experiment, the peripheral speed of the photosensitive drum was 10,
It was carried out under the conditions of 25, 40 cm / sec, and the peripheral speed ratio of the charging device and the photoconductor drum was 1, 3, 5 times. Under any conditions, the electrical resistivity of the fiber material and the electrical resistivity of the surface coating layer were In the case of the same, similar results were obtained, so to avoid complication of the table, division of these conditions in the table was omitted. Further, in the rayon-based fiber material and the nylon-based fiber material, the experiment was repeated in the range of electric resistivity of 10 ⁴ to 10 ⁷ Ωcm. , Because the same result was obtained,
In order to avoid making the table complicated, the division of these conditions in the table is omitted.

[0136]

[Table 7]

Next, various film materials having different electric resistivities were prepared. Here, since the range of the electrical resistivity that can be easily produced varies depending on the type of film material, it is 10 ¹ to
In the range of 10 ⁷ Ωcm and in the range of 10 ⁴ to 10 ⁹ Ωcm for the tetrafluoroethylene-based film material, materials having different electrical resistivities for each digit were produced. As a material having an extremely low resistance, an aluminum-based film material having an electric resistivity of 10 to ⁵ Ωcm was prepared.

In all of these film materials, the film thickness was 50 ± 10 μm, the length of the section 43 was 20 mm,
A film charging device material was produced such that the average sticking interval of the slices 43 was 10 sheets / inch. At this time, the width of the film patch was 10 mm. Subsequently, a conductive fluororubber paint (a mixed paint of DAIEL LATEX GLS-213 and GLS-213D manufactured by Daikin Co., Ltd.) was applied to the surface thereof to prepare a charging device 31 having a plural film form shown in FIG. The coating method at this time includes bar coating, removal of excess coating liquid by a spinner, and 80 ° C. 30
The three steps of minute drying were repeated a plurality of times to finally make the electric resistivity of the surface layer 10 ² to 10 ¹³ Ωcm and the film thickness after the surface coating 130 μm.

In the positional relationship shown in FIG. 6, this charging device has X = 10 mm, Y = 5 mm and Z = 0.2 m.
m, a polyimide film is attached and the surface is insulated, and a SUS plate having a plate thickness t = 0.5 mm is adopted as a regulating member, and is attached to a copying machine whose main part is shown in FIG. I went.

As another evaluation item, the photosensitive drum is charged while the voltage applied to the charging device 2 is fixed at -1.1 kV, and the developing device 3 of the copying machine, the main part of which is shown in FIG. A surface potential meter was attached at the position instead of the developing device 3, and the charged potential on the surface of the photoconductor was measured without image exposure. The results are shown in Table 8.

In the experiment, the peripheral speed of the photosensitive drum was 10,
It was carried out under the conditions of 25, 40 cm / sec, and the peripheral speed ratio of the charging device and the photoconductor drum was 1, 3, 5 times. Under any conditions, the electrical resistivity of the fiber material and the electrical resistivity of the surface coating layer were In the case of the same, similar results were obtained, so to avoid complication of the table, division of these conditions in the table was omitted. In addition, for nylon-based film materials and tetrafluoroethylene-based film materials, we repeated experiments in the range of electrical resistivity of 10 ⁴ to 10 ⁷ Ωcm. Since the same result was obtained, the classification of these conditions in the table was omitted in order to avoid complication of the table.

[0142]

[Table 8]

From the results of Table 7 and Table 8, the following can be understood.

That is, the electric resistance of the surface coating layer is 10 ⁶ Ω
In the case of cm or more, the brush muscle noise evaluation result is rank A in almost all areas, and good image performance can be obtained. It is considered that this is because the spindle-shaped discharge was prevented from spreading due to the increased resistance of the surface coating layer as described above.

However, the electric resistance of the surface coating layer is 1
If it exceeds 0 ¹¹ Ωcm, the image characteristics are good, but another problem of a decrease in charging potential occurs. It is considered that this is because the voltage drop in the surface coating layer became non-negligible due to the higher resistance of the surface coating layer. Also,
Even in the internal brush fiber material and film material, even when the electrical resistivity exceeds 10 ⁶ Ωcm, another problem of reduction in charging potential occurs due to the voltage drop due to these materials.

From the above results and consideration, in the charging device for charging the charging target by applying the potential difference between the charging target and the sliding charging member while sliding the charging member on the surface of the charging target. , The inside of which the sliding friction charging member is rotatably arranged has an electric resistivity of 10 ⁶ Ωcm or less, and an electric resistivity of 1
A plurality of contactors each of which is composed of a surface coating layer of 0 ⁶ to 10 ¹¹ Ωcm, and the deformation when the plurality of contactors rub against the body to be charged is restored after the rubbing. It can be seen that in a charging device in which a plurality of contacts are brought into contact with the regulating member, suitable image performance and charging performance can be obtained.

As a fifth experiment, the image characteristics when voltage was applied to the regulating member was verified, and a detailed description will be given below.

First, similar to the one used in the fourth experiment,
A charging device including a rayon-based brush material and a charging device including a nylon-based brush material having an internal electrical resistivity of 10 ⁵ Ωcm and an electrical resistivity of the surface coating layer of 10 ⁸ Ωcm were manufactured.

In the positional relationship shown in FIG. 6, this charging device has X = 10 mm, Y = 4 mm, Z = 1 mm,
So that the brush fibers are not cut, the plate thickness t = 1 mm is obtained by polishing the tip to R1 mm.
While adopting the SUS plate of No. 3 as a conductive regulating member, it was attached to the copying machine whose main part is shown in FIG.

Then, the SUS regulating member is set to -1.3k.
A bias voltage of V was applied to the charging device 2 at -1.1 kV, and 3,000 copies were made using an original having an image density of 6%. Table 9 shows the result of evaluation of the streak-like image noise for every 1,000 sheets during the copying of 3,000 sheets.

As another comparative experiment, Table 9 also shows the results of the same experiment conducted in a floating state without applying a bias to the regulating member.

In this experiment, image evaluation was performed on two types of charging devices, but there was no difference in the results depending on the type of charging device, and only the difference due to the presence or absence of bias application to the regulating member was confirmed. In order to avoid complication, the classification of charging device types in the table is omitted.

In the experiment, the peripheral speed of the photosensitive drum is 10,
The test was carried out under the conditions of 25, 40 cm / sec, and the peripheral speed ratio of the charging device and the photoconductor drum was 1, 3, 5 times. Therefore, the classification of these conditions in the table is omitted in order to avoid making the table complicated.

[0154]

[Table 9]

Next, similar to the one used in the fourth experiment,
A charging device including a nylon-based film material and a charging device including a tetrafluoroethylene-based film material having an internal electrical resistivity of 10 ⁵ Ωcm and an electrical resistivity of the surface coating layer of 10 ⁸ Ωcm were prepared.

In the positional relationship shown in FIG. 6, this charging device has X = 10 mm, Y = 4 mm, Z = 1 mm,
In order to prevent the film from being cut off, a SUS plate with a plate thickness t = 1 mm, which has been polished so that the leading end is R1 mm, is used as a regulating member, and a copying machine whose main part is shown in FIG. I installed it.

Next, the SUS regulating member is set to -1.3k.
A bias voltage of V was applied to the charging device 2 at -1.1 kV, and 3,000 copies were made using an original having an image density of 6%. Table 10 shows the results of evaluation of the brush streak-shaped image noise for every 1,000 sheets when copying 3,000 sheets.

As a separate comparative experiment, Table 10 also shows the results of the same experiment conducted in the floating state without applying a bias to the regulating member.

In this experiment, image evaluation was performed for two types of charging devices, but there was no difference in the results depending on the type of charging device, and only the difference due to the presence or absence of bias application to the regulating member was observed. In order to avoid complication, the classification of charging device types in the table is omitted.

In the experiment, the peripheral speed of the photosensitive drum is 10,
The test was carried out under the conditions of 25, 40 cm / sec, and the peripheral speed ratio of the charging device and the photoconductor drum was 1, 3, 5 times. Therefore, the classification of these conditions in the table is omitted in order to avoid making the table complicated.

[0161]

[Table 10]

From the results of Table 9 and Table 10, the following can be understood.

That is, the internal electrical resistivity is 10 ⁵ Ωcm.
Thus, in the charging device including a plurality of contacts with the surface coating layer having an electrical resistivity of 10 ⁸ Ωcm, good initial image performance with a brush streak image noise of rank A can be obtained.

However, when these charging devices are actually used for a long period of time, various dusts generated in the copying machine, such as toner powder and paper powder, adhere to the contact parts of the charging device, and the stains are generated. When accumulated, it hinders discharge at the contact tip. Since the charging device is a rotating body, this dirt spreads in the circumferential direction and becomes a streak-like image noise with a slightly wide interval. As is clear from this comparative experiment, 100
The image rank begins to deteriorate even after copying about 0 sheets, and at the time of copying 2000 sheets, the initial image performance deteriorates considerably.

On the other hand, when bias is applied in this experiment, it can be seen that good image performance is maintained even after copying 3,000 sheets. The effect of this bias application can be understood as follows.

Since the voltage applied to the charging device is -1.1 kV, it is considered that most of the stains attached to the contacts are positively charged substances regardless of the type. When −1.3 kV is applied to the regulating member in this state, the positively chargeable substance is transferred and attached to the regulating member due to the voltage relationship between the contactor and the regulating member. Therefore, it can be understood that the dirt of the contactor is electrostatically transferred to the regulating member, and as a result, the contactor itself continues to provide a good image without being affected by discharge during copying of 3000 sheets. In fact, after the experiment,
Since a large amount of dirt, mainly toner powder, was attached, it was possible to confirm the effect of removing bias on the restriction member by applying bias.

The experiment is carried out under the condition that direct discharge does not occur between the regulating member and the photosensitive drum by setting the positional relationship of the regulating member as described above.

From the above results and consideration, in a charging device for charging a charged body by applying a potential difference between the charged body and the sliding charge member while sliding the charging member on the surface of the charged body. The sliding friction charging member is composed of a plurality of rotatably arranged contacts, and the plurality of contacts are rubbed against the body to be charged, and the deformation is restored after the rubbing. It is understood that the charging device in which the contactor is brought into contact with the voltage-applied regulating member provides stable image performance even in long-term use.

[0169]

According to the present invention, compared to the conventional charging device composed of a plurality of contacts, brush streak image noise is improved and a good image can be obtained without impairing the charging performance.
Further, it is possible to provide a highly reliable charging device capable of preventing the streak-like image noise from becoming conspicuous during long-term use.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a main part of a copying machine in which a charging device of the present invention is incorporated and used.

FIG. 2 is a perspective view of a charging device having a brush form according to the present invention.

FIG. 3 is a perspective view of a flocked cloth for forming a charging device having a brush form according to the present invention.

FIG. 4 is a perspective view of a charging device having a multi-film form according to the present invention.

FIG. 5 is a perspective view of a film sticking material for forming a charging device having a multi-film form according to the present invention.

FIG. 6 is a diagram showing a positional relationship of the charging device according to the present invention.

FIG. 7 is a diagram showing a tip portion of a brush fiber material according to the present invention.

FIG. 8 is a diagram showing an edge of a film material according to the present invention.

FIG. 9 is a schematic view showing another form of the charging device according to the present invention.

FIG. 10 is a schematic view showing a modified example of the charging device according to the present invention.

FIG. 11 is a schematic view showing a modified example of the charging device according to the present invention.

FIG. 12 is an enlarged view of a contact portion between a contactor and a member to be charged for explaining the effect of the present invention.

[Explanation of symbols]

1: photoconductor drum, 2: charging device, 3: developing device, 4:
Transfer charger, 5: cleaning device, 6: eraser, 7: intermediate roller pair, 8: timing roller pair, 9: conveyor belt, 11: charging device having brush form, 12: conductive support, 13: brush fiber material Two
1: Flocked cloth, 22: Base cloth, 23: Pile, 31: Charging device having film form, 32: Conductive support, 33:
Film material, 41: Film sticking material, 42: Base material, 4
3: section: 51: outer peripheral line, 52: regulating member, 61: fiber tip portion, 71: film end portion, 81: belt-shaped conductive support, 91: adhering matter removing means, 101: second regulating member

Claims (1)

[Claims] 1. A charging device for charging the surface of a body to be charged, comprising a plurality of contacts movably arranged at a contact position and a non-contact position where the surface of the body to be charged is rubbed. Regulating means for abutting against the child and regulating the moving state of the contactor from the contact position to the non-contact position, and between the contactor and the charged body for charging the surface of the charged body. A charging device comprising means for applying a charging voltage.