JPH0488376A - Production of developer carrying member - Google Patents

Abstract

PURPOSE:To easily and inexpensively produce the above carrying member by putting a shaft core and conductive elastomer compsn. into a forming mold having microruggedness on inside walls and molding a conductive elastic layer having the microruggedness on the surface, then taking out the molding, embedding a dielectric material into the recessed parts of the surface to integrate this material to the surface elastic layer, then subjecting the surface to a smoothing treatment. CONSTITUTION:The shaft core and the conductive elastomer compsn. are put into the forming mold having the microruggedness on the inside walls and after the conductive elastic layer having the microruggedness on the surface is molded on the shaft core, the molding is taken out. The dielectric material is then embedded into the recessed parts of the surface to integrate this material to the surface elastic layer and thereafter, the surface is subjected to the smoothing treatment. The conductive elastomer compsn. and the elastomer to be used for the dielectric material are particularly preferably silicone rubber in terms of low hardness, environmental resistance, and release property, etc. The developer carrying member is easily and inexpensively produced in this way.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention supplies a non-magnetic component developer externally added with an auxiliary agent as necessary to a rotationally driven developer carrier, and The developer is carried on the surface of a developer carrier, and the electrostatic latent image formed on the latent image carrier is transferred to a development area where the latent image carrier and the developer carrier face each other. The present invention relates to a method for manufacturing a developer carrier used in an image forming method in which an image is visualized by the developer carried on the developer carrier.

[Conventional technology]

Image forming devices such as electronic copying machines, printers, and facsimile machines that form an electrostatic latent image on a latent image carrier and visualize it with a developer to obtain a recorded image use a dry type that uses a powdered developer. This developing device is widely used.

As such powder-like developers, two-component developers containing toner and a carrier and two-component developers not containing a carrier are known. Two-component developers using the former two-component developer Although this method allows relatively stable and good recorded images to be obtained, carrier deterioration and toner-to-carrier mixing ratio fluctuations are likely to occur, the maintenance and management of the device is complicated, and the overall structure of the device tends to increase in size. It has its drawbacks.

From this point of view, a one-component development system using a two-component developer that does not have the above-mentioned drawbacks is attracting attention. - Component type developers include those consisting only of toner and those consisting of a mixture of toner and an auxiliary agent, to which an auxiliary agent is externally added as required. Furthermore, toners include magnetic toners in which magnetic powder is kneaded into each toner particle itself, and non-magnetic toners that do not contain magnetic material.

Here, since magnetic materials are generally opaque, when a full-color or multi-color image is formed using magnetic toner, the developed visible image becomes unclear, making it impossible to obtain a vivid color image. Therefore, especially for color development.

It is desirable to adopt a one-component development method using non-magnetic toner.

By the way, in a developing device that employs a -component development method, a -component developer is carried on a developer carrier and transported, and in a development area where the developer carrier and the latent image carrier face each other, The electrostatic latent image formed on the latent image carrier is made into a visible image using a developer, but in order to form a high-quality visible image with a predetermined density, a large amount of sufficiently charged toner must be applied to the development area. It is necessary to convey the latent image and visualize the latent image using the toner.

When magnetic toner is used, the two-component developer can be carried on the developer carrier by using the magnetic force of the magnet installed inside the developer carrier, so the above requirements can be met relatively easily. Is possible.

However, when a nonmagnetic two-component developer is used, it is difficult to satisfy the above requirements because it cannot be supported on a developer carrier by magnetic force. Various countermeasures against this problem have been proposed in the past, for example, in Japanese Patent Application Laid-Open No. 61-42672.

Dielectric (insulator) on the surface of the developer carrier (developing roller)
A developer supplying member made of, for example, a sponge roller is pressed into contact with the layer, and both are frictionally charged to opposite polarities, and non-magnetic toner charged to the opposite polarity to the dielectric is applied. A method has been proposed in which the -component developer is electrostatically deposited on a dielectric and transported to a development area. However, even with this method, it is not possible to sufficiently increase the strength of the electric field formed near the dielectric surface, so it is difficult to carry a large amount of toner on the surface of the developing roller. Due to the insufficient amount of agent, it is difficult to form a high-density visible image.

Furthermore, a configuration in which an electric field is applied between the developing roller and the developer supply member in a direction that electrostatically transfers non-magnetic toner toward the developing roller is also known, but even if such a configuration is added, , it is difficult to make a sufficient amount of toner adhere to the developing roller.

In addition, as a toner supply member, 102 to 106 Ω・C
m conductive foam (Japanese Unexamined Patent Publication No. 60-229057)
, elastic body with skin layer (Japanese Unexamined Patent Publication No. 60-229060) and fur brush (Japanese Unexamined Patent Publication No. 61-42672)
It has been proposed to use a metal body with an uneven surface (Japanese Patent Laid-Open No. 60-53
No. 976), integrated insulation coated roller (Japanese Patent Application Laid-Open No. 55-4
No. 6768) Medium and low antibody coated roller (Japanese Patent Application Laid-open No. 58-1
3278) and #0! An electrode roller (Japanese Unexamined Patent Publication No. 5336245) having an edge and a conductive surface has been disclosed.

Furthermore, in a developing device using a non-magnetic component developer,
In Japanese Patent Application Laid-Open No. 60-229057, a sponge roller,
JP-A No. 62-229060 uses an elastic roller, and JP-A No. 61-52663 uses a fur brush or the like to apply an electric charge to the toner through frictional charging between the toner and a replenishing member, and furthermore, by contact with a developing roller. Friction causes the toner to electrostatically adhere to the developing roller, and a layer thickness regulating member such as a blade is used to control the toner layer to develop the latent image on the photoreceptor. Various materials are used for the developing roller, such as insulating materials, medium resistance materials, and laminated materials.

According to the methods shown in these references, toner adhesion to the developing roller is achieved by frictional electrification between the toner replenishing member and the developing roller, but sufficient electrification cannot be achieved due to friction between the toner-attached member. This results in insufficient toner adhesion. The optimum adhesion amount and charge amount in the non-magnetic component development method will be explained as follows.

For black and white, emphasis is placed on the amount of charge, which is -10~ for boat fishing.
It is 20μC/g. If the value is smaller than this value, the image quality will be poor in terms of background stains, sharpness, etc.

Regarding the amount of adhesion, the amount of adhesion on the developing roller is 0.
1-0.3mg/c+a2, but 0.3mg/c+a2 on the transfer paper.
4-0.5111 g/cI112 is required, and the amount of toner adhesion is covered by increasing the speed of the developing roller to 3 to 4 times the speed of the photoreceptor. just,
When the developing roller rotates 3 to 4 times, there is a problem in that the phenomenon of "toner from the trailing edge" occurs, that is, when a solid area is developed, the density at the trailing edge of the image becomes higher. . To prevent this phenomenon, the speed of the developing roller should be made close to the speed of the photoreceptor. In other words,
It is necessary to increase the amount of adhesive on the developing roller and reduce the rotation speed.

On the other hand, with color toner, the degree of coloring is lower than that of black toner, and if you try to improve the "from the trailing edge of the toner", the color characteristic is 0.8 to 1.2 m, which is even more than that of black toner.
An amount of adhesion on the developing roller of g/cm2 is required.

In addition, regarding the amount of charge, in order to obtain a stable image, 5 to 20 μC/g (preferably 10 to 15 μC/g)
A value of is desired.

As a method to solve these problems, the present inventors
First, a one-component developer consisting of a non-magnetic toner to which an adjuvant is externally added as necessary is supplied to a rotationally driven developer carrier, and the developer is carried on the surface of the carrier. In a developing area where the latent image carrier and the developer carrier face each other, the electrostatic latent image formed on the latent image carrier is made visible by the developer carried on the developer carrier. In the developing method for image formation, a large number of minute electric fields are formed near the surface of the developer carrier by selectively holding charges on the surface of the developer carrier, and the charged toner is attracted by the closed electric field, The developer is attached and supported on the surface of the developer carrier,
We proposed an image forming method in which an electrostatic latent image is visualized using the developer carried thereon.

In this method, a large number of microfields are formed near the surface of the developer carrier, so the field strength can be significantly increased compared to conventional methods, and a large amount of charged non-magnetic toner can be removed. It has many advantages such as being able to be carried on a developer carrier and transported to a developing area.

However, sufficient research has not yet been conducted on an industrially advantageous manufacturing method for the developer carrier used in such a method, and a solution to this problem has been desired.

[Problem to be solved by the invention]

An object of the present invention is to form a large number of microfields near the surface of the developer carrier, hold toner on the carrier by the microfields, and then develop an electrostatic latent image in a development area. In this method, the surface of the developer carrier and the electrostatic latent image carrier are separated in the development region without requiring a troublesome means of maintaining and managing a constant distance between the surface of the developer carrier and the surface of the electrostatic latent image carrier in the development region. It is an object of the present invention to provide a simple and inexpensive manufacturing method for a developer carrier used in a developing method that brings the developer into contact with the surface of the electrolatent image carrier and does not impair developability such as uneven development density.

[Means to solve the problem]

That is, according to the present invention, a large number of dielectric micro regions made of a dielectric material made of a conductive elastic member main body and provided independently and spaced apart on at least the surface thereof are provided on the axis. It has an elastic surface layer. In a method for manufacturing a developer carrier used for electrostatic latent image development, a shaft core and a conductive elastomer composition are placed in a mold having fine irregularities on the inner wall, and a conductive elastic layer having fine irregularities on the surface is placed. After molding on the axis, the developer carrier is taken out, a dielectric material is embedded in the surface recesses, and the dielectric material is integrated with the surface elastic layer, and the surface is smoothed. A method is provided, and the elastic device is provided with a conductive elastic member body having a plurality of dielectric micro regions made of a dielectric material provided independently and spaced apart on at least the surface of the conductive elastic member body on the axis thereof. In a method for manufacturing a developer carrier having a surface layer and used for electrostatic latent image development, a large number of minute protrusions made of a dielectric material are attached to the inner wall of a mold, and then a shaft core and a conductive elastomer composition are attached. The developer carrier, in which an elastic surface layer is integrated on the axis and minute protrusions made of the dielectric material are embedded in the elastic surface layer, is removed, and the developer carrier is removed as necessary. A method for manufacturing a developer carrier is provided, which comprises subjecting the surface to a smoothing treatment.

By using the developer carrier obtained by the method of the present invention, a precise gap can be formed between the developer carrier and a rigid latent image carrier such as a photoreceptor provided with photoconductivity on a metal drum. There is no need for maintenance and management, and design tolerances can be widened.

First, an image forming method using a developer carrier manufactured by the method of the present invention will be described.

FIG. 1 shows an outline of a typical developing device useful for carrying out this image forming method, centering on the developer carrier section. In FIG. 1, toner 6 contained in a toner tank 70 is shown.
0 is a toner supply member (sponge roller, fur brush, etc.) 4 by a stirring blade (toner supply auxiliary member) 50.
0, the toner 60 is forcibly brought to the toner supply member 4
0. On the other hand, the developer carrier (
The developing roller (for example, 20φ) 20 rotates in the direction of the arrow (for example, 10100 rpm) and reaches the contact portion with the toner supply member 40. The toner supply member 40 rotates in the opposite direction to the developer carrier 20 (for example, 67 rpm) L , , charges the developer carrier 20 and the toner 60, and charges the developer carrier 20 and the toner 60.
A toner 60 is applied thereon. Further, the developer carrier 20 rotates, and the toner adhered on the developer carrier 20 reaches the development area 80 with its thickness being controlled and its charging stabilized by the toner layer thickness regulating member (elastic blade) 30. In the development area 80, the developer carrier 20 and the latent image carrier 1
The latent image on the latent image carrier 10 is developed by bringing the latent image carrier 10 into rotational contact with the latent image carrier 10 in the same direction on its surface (rotational speed of the latent image carrier: 120 rpm, for example). Here, if necessary, a direct current is applied to the developer carrier 20 and the toner supply member 40.

An optimal image can be controlled by applying a bias 90 such as alternating current, direct current superimposed alternating current, or pulse.

In addition, setting the amount of deformation of the surface elastic layer on the surface of the developer carrier in the development area to be less than 3710 times the thickness of the elastic layer prevents deformation of the entire developer carrier, and also prevents vibrations caused by contact. Preferable for suppressing occurrence.

Next, a method for manufacturing the developer carrier of the present invention will be explained.

The first method of the present invention for producing a developer carrier is to place a core and a conductive elastomer composition into a mold having minute irregularities on the inner wall, and place a conductive elastic layer having minute irregularities on the surface into a mold. This is a method in which a molding process is performed on the surface, the surface is taken out, a dielectric material is buried in the surface recessed portions, and the dielectric material is integrated with the surface elastic layer, followed by smoothing the surface.

As a method for providing minute irregularities on the inner wall of the mold, a conventionally known method such as a sandblasting method or a knurling method is employed.

Further, as the conductive elastomer composition, a composition in which a conductivity imparting agent is added to a nidistomer (rubber material) is used.

Examples of elastomers include the following:

Styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), nitrile-butadiene rubber (NBR), nitrile-isoprene rubber (NI
R), diene rubber such as chloroprene rubber (CR);
Butyl rubber (IIR), ethylene-propylene rubber (E
PM, EPDM), chlorosulfonated polyethylene (
Olefin rubbers such as (1, SM); ether rubbers such as epichlorohydrin rubber (CHR1CHC); other silicone rubbers, fluororubbers, acrylic rubbers, urethane rubbers, as well as styrene rubbers, olefin rubbers, polyvinyl chloride rubbers, and urethane rubbers. , elastomer materials such as thermoplastic elastomers such as polyester, polyamide, fluorine, and chlorinated polyethylene.

In addition, conductivity imparting agents include metal powders such as Ni and Cu; carbon blacks such as furnace black, lamp black, thermal black, acetylene black, and channel black; tin oxide, zinc oxide, molybdenum oxide, antimony oxide, and titanic acid. Conductive oxides such as potash; electroless plated materials such as titanium oxide and mica; inorganic fillers such as graphite, metal fibers, and carbon fibers; surfactants; and the like.

Furthermore, organic ion conductors in which metal ions are coordinated to a polymer matrix such as polyethylene oxide or polysiloxane can also be used.

As the shaft core, a conductive substrate such as AQ, Fe, S
Metallic materials such as O8 are used.

Further, the dielectric material embedded in the surface of the elastic surface layer is 1013Ω・0m or more, preferably 1014Ω・0m or more.
Those with a length of 0 m or more are used.

Further, the average particle diameter is preferably 30 tones or more, preferably 50 μs or more. If it is less than 30, it is difficult to form a microfield and stable toner adhesion and charging cannot be obtained. Incidentally, although it does not matter whether the shape is fixed or irregular, it is better to use a shape having an irregular shape in that the dielectric material does not separate from the conductive elastomer during the surface smoothing process.

These specific materials include alumina, beryllia,
Inorganic particles such as magnesia, silicon nitride, boron nitride, mullite, steatite, forsterite, zircon, cordierite, epoxy resin, fluororesin, silicone resin, acrylic resin, polyamide resin, polystyrene resin, phenolic resin, Examples include organic particles such as melamine resin and polyethylene resin, but in the present invention, it is preferable to use an elastomer as the dielectric material.

As the elastomer in this case, the same material as the elastomer used for the conductive elastomer is used.

Dielectric elastomer particles can be produced by freezing the elastomer with dry ice or the like and then crushing it into a powder, crushing it with a grinder and pulverizing it, or forming an aqueous emulsion using a surfactant, etc. A known method such as a curing method is employed.

In addition, as the elastomer used for the conductive elastomer composition and the dielectric material, silicone rubber is particularly preferred from the viewpoint of low hardness, environmental resistance, mold releasability, and the like.

The second method of the present invention for manufacturing a developer carrier is to attach a large number of minute protrusions made of a dielectric material to the inner wall of a mold, and then insert a shaft core and a conductive elastomer composition.
A method of taking out a developer carrier having an integrated elastic surface layer on its axis and having minute protrusions made of the dielectric material embedded in the elastic surface layer, and subjecting the surface to smoothing treatment as necessary. It is.

In this case, the same materials as those used in the first method can be used as the conductive elastomer composition, shaft core, and dielectric material.

In addition, in this second method, in order to attach a large number of minute protrusions made of dielectric material to the inner wall of the mold, adhesive is first applied to the inner wall surface, and then dielectric material (insulating material) is applied on the inner wall surface. It can be obtained by dusting the powder. Another method is to apply a water-repellent or oil-repellent material such as a fluorine-based surfactant to the inner wall, and then spray a solution or emulsion of an insulating material such as resin or elastomer onto the inner wall surface. After forming the droplets,
A method for solidifying is exemplified.

Further, as the smoothing method, conventionally known cutting or polishing processes can be used as they are.

As the mold used in the first and second methods above, a warp mold is the simplest and preferable, but
Alternatively, a pull-out type may be used, and in this case, for example, the liquid elastomer is heated, hardened and molded, and then cooled to shrink the molded product, so that it can be easily pulled out.

Further, the area of the surface dielectric portion of the developer carrier used in the present invention is preferably in the range of 50 to 80'1, and the amount of dielectric material added is adjusted as appropriate so that the area falls within this range after the carrier is prepared. .

In addition, in the present invention, when the developer carrier and the latent image carrier are used for development while rotating in the same direction and at approximately the same speed as shown in FIG. It is preferable that the strain (JIS K 6301) is 25 or less. This allows a sufficient amount of toner to be carried and transported on the developer carrier, and also suppresses the occurrence of vibrations caused by contact rotation with both carriers, thereby reducing the occurrence of uneven development. It has the advantage of not being

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that parts represent parts by weight.

Example 1 Conductive silicone rubber (trade name DY32-700) was applied to the surface of an SUS metal roller coated with a conductive primer (trade name DY39-011; manufactured by Toray Silicone Co., Ltd.) in advance.
u: manufactured by Toray Silicone Co., Ltd.) and placed in a warp-type press molding mold with square groove knurling of 0.4 mm pitch and 0.5 mm depth on the inner wall.
Next vulcanization (170℃/10 minutes, 120kgf/c river 2),
Secondary sulfurization (200°C for 74 hours) was performed and molding was performed. Next, after applying X and Y primers (manufactured by Toray Silicone Co., Ltd.) to the surface of the molded product taken out from the molding machine, a soft silicone resin (trade name 5R2407: manufactured by Toray Silicone Co., Ltd.) is spray-coated to soften the concavities on the surface. Filled with silicone resin. After curing this at 150° C. for 71 hours, the surface was polished to prepare a developer carrier.

Example 2 After applying a 50% l-luene solution of liquid silicone rubber (trade name DX35-203: manufactured by Toray Silicone Co., Ltd.) to the entire inner wall of a warp-type press-molded metal, silicone rubber particles (trade name manufactured by Toray Silicone Co., Ltd.) were applied. Name 5E1185
Particles (with an average particle size of about 200 μm obtained by freeze-pulverizing and classifying U) were sprinkled and dried. Next, as in Example 1, a metal roller wrapped with conductive silicone rubber was placed in a molding machine, vulcanized and molded under the same conditions as in Example 1, and then the surface was polished to support the developer. The body was created.

〔Effect of the invention〕

According to the manufacturing method of claims (1) and (2), a developer carrier used for electrostatic latent image development, which has a conductive elastic layer on the axis and on the surface of which independent minute dielectric portions are present, can be easily produced. Moreover, it can be manufactured at low cost.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view centered on a developer carrier portion showing an example of a developing device in which a microfield electric field is formed on a developer carrier useful for carrying out the present invention. 10... Electrostatic latent image carrier, 20... Developer carrier,
30... Toner layer thickness regulating member, 40... Toner supply member, 50... Stirring blade, 60... Toner, 70...
- Toner tank, 80... Development area, 90... Bias. Figure 1

Claims (2)

[Claims] (1) An elastic surface layer consisting of a conductive elastic member main body and having a large number of dielectric micro regions made of dielectric material provided independently and at intervals on at least the surface thereof, on the axis. In the method for manufacturing a developer carrier used for electrostatic latent image development, a core and a conductive elastomer composition are placed in a mold having minute irregularities on the inner wall, and a conductive elastic layer having minute irregularities on the surface. After molding on the axis, the developer carrier is taken out, a dielectric material is embedded in the surface recesses, and the dielectric material is integrated with the surface elastic layer, and the surface is smoothed. Method. (2) An elastic surface layer consisting of a conductive elastic member main body and having a large number of dielectric micro regions made of a dielectric material provided independently and at intervals on at least the surface thereof, on the axis. In the method of manufacturing a developer carrier used for electrostatic latent image development, the method involves attaching a large number of minute protrusions made of a dielectric material to the inner wall of a mold, and then inserting a shaft core and a conductive elastomer composition. , take out the developer carrier in which the elastic surface layer is integrated on the axis and in which the fine protrusions made of the dielectric material are embedded in the elastic surface layer, and if necessary, smooth the surface. A method for manufacturing a developer carrier, characterized in that: