JP2968979B2 - Developer carrier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention supplies a non-magnetic one-component developer externally supplemented with an auxiliary agent as necessary to a rotatable developer carrier,
Carrying and transporting the developer on the surface of the developer carrier,
In a developing region where the latent image carrier and the developer carrier are opposed to each other, the electrostatic latent image formed on the latent image carrier is visualized by the developer carried on the developer carrier. The present invention relates to a developer carrier used in an image forming method.

[Conventional technology]

An image forming apparatus such as an electronic copier, a printer or a facsimile that forms a latent image on a latent image carrier and visualizes the latent image with a developer to obtain a recorded image is a dry type using a powdery developer. Is widely used.

As such a powdery developer, a two-component developer having a toner and a carrier and a one-component developer without a carrier are known, and two-component development using the former two-component developer is known. In the method, although a relatively stable and good recorded image is obtained, deterioration of the carrier and fluctuation of the mixing ratio of the toner and the carrier are apt to occur, maintenance of the apparatus is complicated, and the structure of the entire apparatus is easily enlarged. Has disadvantages.

From such a viewpoint, a one-component developing method using a one-component developer which does not have the above-mentioned disadvantages has attracted attention. The one-component developer includes a toner composed of only a toner and a toner obtained by externally adding an auxiliary agent as needed and mixing the toner and the auxiliary agent. As the toner, there are a magnetic toner in which magnetic powder is kneaded into each toner particle itself, and a non-magnetic toner containing no magnetic material.

Here, since the magnetic material is generally opaque, if a color image including full-color or multi-color is formed with magnetic toner, the developed visible image becomes unclear and a vivid color image cannot be obtained. Therefore, it is desirable to adopt a one-component developing method using a non-magnetic toner especially for color development.

By the way, in a developing device employing a one-component developing method, a one-component developer is carried on a developer carrier and transported. In a developing region where the developer carrier and the latent image carrier are opposed to each other, The electrostatic latent image formed on the latent image carrier is visualized with a developer, but in order to form a high quality visible image of a predetermined density, a large amount of sufficiently charged toner must be applied to the developing area. The latent image needs to be conveyed and visualized with the toner.

In the case where a magnetic toner is used, the one-component developer can be carried on the developer using the magnetic force of a magnet provided in the developer carrier, so that the above-mentioned requirement can be satisfied relatively easily. It is possible.

However, when a non-magnetic one-component developer is used,
Since this cannot be carried on the developer carrying member by magnetic force, it is difficult to satisfy the above requirements. Various countermeasures against this have been proposed in the past. For example, JP-A-61-42672 discloses a developer carrier (developing roller).
A layer of a dielectric (insulator) is formed on the surface of the substrate, and a developer supply member such as a sponge roller is pressed against the layer to frictionally charge the two with different polarities. A method has been proposed in which a non-magnetic toner charged to a polarity is electrostatically attached to a dielectric and such a one-component developer is transported to a development area. However, even with this method, the strength of the electric field formed in the vicinity of the dielectric surface cannot be sufficiently increased, so that it is difficult to carry a large amount of toner on the surface of the developing roller, and the developing roller can be transported to the developing area. Insufficient amounts of the agent make it difficult to form a high-density visible image.

A configuration in which a non-magnetic toner is applied between the developing roller and the developer supply member in a direction in which the non-magnetic toner is electrostatically transferred to the developing roller is also known, but even if such a configuration is added, It is difficult to attach a sufficient amount of toner to the developing roller.

Examples of the toner supply member include a conductive foam of 10 ² to 10 ⁶ Ω · cm (JP-A-60-229057), an elastic body with a skin layer (JP-A-60-229060), and a fur brush. (Japanese Patent Application Laid-Open No. 61-42672) and the like, and as a developing roller, a metal body having an uneven surface (Japanese Patent Application Laid-Open No. 60-53976), an insulating coated roller body ( Japanese Unexamined Patent Publication No. Sho 55-46768 discloses a medium resistance coated roller (Japanese Unexamined Patent Publication No. 58-13278) and an electrode roller having an insulator and a conductive surface (Japanese Unexamined Patent Publication No. Sho 53-36245). .

In a developing apparatus using a non-magnetic one-component developer, a sponge roller is disclosed in JP-A-60-229057, an elastic roller is disclosed in JP-A-62-222960, and a developing roller is disclosed in JP-A-61-52663.
In the publication, a fur brush or the like is used to apply electric charge to the toner by frictional charging between the toner and the replenishing member, and further, by friction in contact with the developing roller, electrostatically attaches the toner to the developing roller. The latent image on the photosensitive member is developed by controlling the toner layer using a layer thickness regulating member such as a blade. As the material of the developing roller, various materials such as an insulating material, a medium-resistance material, and a laminated material are used.

According to the methods described in these references, toner is adhered to the developing roller by frictional charging between the toner replenishing member and the developing roller. And toner adhesion is insufficient. The following describes the optimal amount of adhesion and the amount of charge in the non-magnetic one-component developing system.

For black and white, the charge amount is important, and it is generally 10 to
20 μC / g. If the value is smaller than this value, the image quality such as background smear and sharpness is inferior. Regarding the coating weight, although the adhesion amount on the developing roller is 0.1 to 0.3 mg / cm ^2, the transfer paper is required 0.4~0.5mg / cm ^2, the speed of the developing roller of the photosensitive body speed 3 to 4 times, the amount of adhered toner is covered. However,
For the rotation of the developing roller 3 to 4 times, "from the rear end of the toner"
That is, there is a problem that when the solid portion is developed, a phenomenon that the density at the rear end of the image becomes high occurs. In order to prevent this phenomenon, the speed of the developing roller should be close to the speed of the photoconductor. That is, the number of rotations must be reduced by increasing the amount of adhesion on the developing roller.

On the other hand, in the color toner, the color characteristics are small in degree of coloring in comparison with black toner, and when you try to improve the "from toner rear", further more 0.8~1.2mg / cm ² compared to the black toner
Is required on the developing roller. Also, regarding the charge amount, in order to obtain a stable image, 5 to 20 μm
A value of C / g (preferably 10-15 μC / g) is desired.

As a method for solving these problems, the present inventors have previously described "a one-component developer composed of a non-magnetic toner externally supplemented with an auxiliary agent as needed on a rotatable developer carrier." The developer is carried on the surface of the carrier, and is conveyed. The electrostatic latent image formed on the latent image carrier is developed in a developing area where the latent image carrier and the developer carrier face each other. In a developing method of visualizing an image with the developer carried on a developer carrier, a plurality of minute particles are formed in the vicinity of the surface of the carrier by selectively holding electric charges on the surface of the developer carrier. An image forming method in which a closed electric field is formed, the charged toner is sucked by the closed electric field, the developer is adhered to and supported on the surface of the developer carrier, and the electrostatic latent image is visualized by the carried developer. Suggested.

According to this invention, since a large number of minute closed electric fields (microfields) are formed in the vicinity of the surface of the developer carrying member, the intensity of the electric field can be significantly increased as compared with the related art,
This has many advantages such that a large amount of a sufficiently charged non-magnetic toner can be carried on a developer carrier and conveyed to a development area.

[Problems to be solved by the invention]

However, even in the image forming method in which a large number of microfields are formed in the vicinity of the surface of the developer carrier as described above, in order to obtain a stable toner adhesion amount and charge amount over time, the developer carrier surface For example, it is required to prevent toner from adhering to the toner, that is, to prevent toner filming.

Accordingly, an object of the present invention is to provide a developer carrying member which can obtain a stable toner adhesion amount and a toner charging amount over time and eliminate the problem of filming in the image forming method. is there.

[Means for solving the problem]

The present inventors have conducted intensive studies and as a result, on the surface of the developer carrier, a developer carrier containing a substance which is non-adhesive to toner in a dielectric portion corresponding to a sea portion has been developed for the above purpose. They found that they fit, and completed the present invention.

That is, according to the present invention, the following inventions are provided.

(1) A developer carrying member in which a derivative portion and a conductive portion are distributed on the surface, and the dielectric portion is frictionally charged by the toner supply member to selectively place on the surface of the developer carrying member. By holding electric charges, a number of minute closed electric fields are formed in the vicinity of the surface of the developer carrier, and a non-magnetic one-component developing system comprising a toner to which an auxiliary agent is externally added as necessary, on the developer carrier. The developer is supplied by a toner supply member in contact with the developer carrier, and the developer is carried on the surface of the developer carrier by the micro-closed electric field, and the electrostatic latent image is visualized by the carried developer. A developer carrying member used in an image forming method, wherein a dielectric portion and a conductor portion are formed on at least the surface thereof, and the dielectric portion contains a substance which is non-adhesive to toner. A developer carrier, characterized in that:

(2) The developer carrying member has a dielectric portion and a conductive portion distributed on the surface, and the dielectric portion is frictionally charged by the toner supply member to selectively place on the surface of the developer carrying member. By holding electric charges, a number of minute closed electric fields are formed in the vicinity of the surface of the developer carrier, and a non-magnetic one-component developing system comprising a toner to which an auxiliary agent is externally added as necessary, on the developer carrier. The developer is supplied by a toner supply member in contact with the developer carrier, and the developer is carried on the surface of the developer carrier by the micro-closed electric field, and the electrostatic latent image is visualized by the carried developer. Developer carrier used in an image forming method, wherein a dielectric portion and a conductor portion are formed on at least the surface thereof in a sea-island structure, and the dielectric portion corresponding to the sea portion is non-adhesive to toner. Characterized by containing a substance that is The developer carrying member.

(3) An electrostatic latent image carrier carrying an electrostatic latent image and a developer carrier carrying a developer are opposed to each other in a developing section, and the electrostatic latent image can be removed by the developer in the developing section. In the developing device for visualization, the developer carrier has a dielectric portion and a conductor portion, or the dielectric portion and the conductor portion are formed in a sea-island structure, and the dielectric portion or the sea portion is formed. The corresponding dielectric portion contains a substance that is non-tacky to the toner, and the toner supply member frictionally charges the dielectric portion to hold the charge, and the conductive portion is charged by the charge of the dielectric portion. By the electrostatic induction generated in response to the electric charge, the electric charge is charged to an amount corresponding to the electric charge in the opposite polarity to the electric charge, thereby forming an electric charge arrangement on the surface of the phenomenon agent carrier. An auxiliary agent was externally added to the surface of the formed developer carrier as needed. The non-magnetic one-component developer consisting of toner supplied by the toner supply member which abuts against the developer carrying member, a developing device, characterized in that for holding the developer charged by the micro 閉電 field. According to the image forming method using the developer carrying member of the present invention, a large number of minute closed electric fields are formed near the surface of the developer carrying member. On the surface of the agent carrier, the dielectric part corresponding to the sea area is made to contain a substance that is non-adhesive to toner, so that toner filming is prevented and stable over time. As a result, a desired toner adhesion amount and a desired toner charge amount can be obtained.

 Hereinafter, such an image forming method will be described.

FIG. 1 shows an outline of a typical developing device useful for carrying out this image forming method, focusing on a developer carrying portion. First
In the figure, the toner 60 contained in the toner tank 70 is
Is forcibly brought to a toner supply member (such as a sponge roller or a fur brush) 40 by a stirring blade (toner supply auxiliary member) 50, and the toner 60 is supplied to the toner supply member 40. On the other hand, the developer carrier (developing roller) 20 of the present invention after development is rotated in the direction of the arrow (for example, 400 rpm).
Then, it reaches a 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, 300 rpm)
Then, the developer carrier 20 and the toner 60 are charged, and the toner 60 adheres to the developer carrier 20. Further, the developer carrier 20
The toner adheres on the developer carrier 20 is rotated by the toner layer thickness regulating member (elastic blade) 30 to stabilize the charge while controlling the thickness, and reaches the developing region 80. In the development area 80, the latent image is developed by contact or non-contact development. Here, if necessary, a bias such as direct current, alternating current, superimposed direct current alternating current, or pulse may be applied to the developer carrier 20 and the toner supply member 40 to control an optimal image.

Next, the mechanism of toner adhesion to the developer carrier 20 of this type (electrode type) will be described. As an example of the developer carrier 20, for example, as shown in FIG.
On its surface, a dielectric region (dielectric portion) and a conductive region (conductive portion) are configured to be mixed with a small area.
The size of the area is 10 mm in diameter if the shape is circular.
Small areas of up to 500 μm are dispersed randomly or according to a certain rule. As the area ratio, the area of the conductor portion is preferably in the range of 20 to 60%. Further, the surface of the dielectric portion is lower than the surface of the conductor portion (that is, concave), and the difference (depth) is preferably about 3 to 6 times the average particle diameter of the toner.

The toner adhesion is as follows. First, the developer carrier 20 that has completed the development rotates in the direction of the arrow and comes into contact with the toner supply member 40. Here, the remaining toner in the non-image portion that has not been developed is mechanically and electrically scraped off by the toner supply member 40, and the dielectric portion is charged by friction. At this time, the charges of the developer carrier 20 and the toner by the previous development are fixed and initialized by friction. Next, the toner carried by the supply member 40 is charged by friction and adheres to the dielectric portion of the developer carrier 20 electrostatically. At this time, the polarity of the toner is opposite to the charge of the photosensitive member, and the dielectric portion of the developer carrier 20 has the same polarity. In the process of toner supply and initialization by the contact rotation between the developer carrier 20 and the toner supply member 40, the dielectric part surface is lowered (concave), so that the dielectric part and toner supply The contact rotation with the member 40 is optimized, and as a result, toner filming on the surface of the dielectric portion is prevented, and the driving torque of the developer carrier 20 is reduced to prevent rotation unevenness.

At this time, the electric field on the developer carrier 20 becomes a microfield (closed electric field) as shown in FIG. 2, and becomes an electric field having a large electric field gradient, so that the toner can be attached to multiple layers. Become. Further, since the attached toner has a closed electric field, the toner is hardly attracted to the developer carrying member 20 and is hard to be attracted.

The thickness of the toner layer is further controlled by the toner layer thickness regulating member 30, and reaches the developing region 80. Development area 80
The electric field between the developer carrier 20 and the electrostatic latent image carrier (photoreceptor) 10 causes the electrode effect to increase, and the toner on the developer carrier 20 tends to adhere to the electrostatic latent image carrier 10 An electric field is generated, and development is performed.

Next, the developer carrier of the present invention will be described. As described above, the developer carrier of the present invention has a dielectric part and a conductor part formed in a sea-island structure on its surface, and the derivative part contains a substance that is non-adhesive to toner. It is characterized by having been done.

It is preferable that the material used for the dielectric portion corresponding to the sea has non-adhesiveness to the toner and has an insulating property (10 ¹³ Ω · cm or more). Specifically, those mainly containing an aliphatic fluorinated compound or a silicone resin are used.

As the aliphatic fluorinated compound, for example, polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkylvinyl ether copolymer, tetrafluoroethylene-ethylene copolymer, Examples thereof include a fluorine-containing polymer such as polychlorotrifluoroethylene or an aliphatic fluorocarbon or an aliphatic fluorochlorocarbon compound having a polar group such as an ether group, a carboxyl group, or a hydroxyl group at the molecular chain terminal or in the molecular chain. Examples of the silicone resin include a condensation reaction type, an addition reaction type, and a peroxide curing reaction type silicone resin or a modified resin obtained by copolymerizing an organic resin.

On the other hand, as a conductive material used for a conductor portion corresponding to an island portion, a conductive material having a resistivity of 10 ¹² Ω · cm or less, preferably 10 ⁸ Ω · cm or less can be used. Specific examples are Al, SUS, F
In addition to metals such as e and Ni, ceramics, and the like, organic polymers to which a conductive filler is added may be mentioned. In this case, the following are mentioned as organic polymers.

Vinyl resins such as polyvinyl chloride, polyvinyl butyral, polyvinyl alcohol, polyvinylidene chloride, polyvinyl acetate, and polyvinyl formal; polystyrene resins such as polystyrene, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer; polyethylene , Polyethylene-based resins such as ethylene-vinyl acetate copolymer; acrylic resins such as polymethyl methacrylate, polymethyl methacrylate-styrene copolymer; polyacetal, polyamide, cellulose, polycarbonate, phenoxy resin, polyester, fluororesin, polyurethane, Phenolic resin,
Resin materials such as urea resin, melamine resin, epoxy resin, unsaturated polyester resin, silicone resin; natural rubber,
Isoprene rubber, butadiene rubber, styrene-butadiene rubber, butyl rubber, ethylene-propylene rubber, chloroprene rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, nitrile rubber, acrylic rubber, urethane rubber, polysulfide rubber, silicone rubber, fluoro rubber, silicone modified Rubber materials such as ethylene-propylene rubber.

Examples of the conductive filler 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, potassium titanate. And electroless plating products obtained by plating on titanium oxide and mica; graphite, metal fibers, carbon fibers, and the like.

Note that an organic ion conductor in which metal ions are coordinated with a polymer matrix such as polyethylene oxide or polysiloxane can also be used.

To produce the developer carrier of the present invention, for example,
(I) First, a metal roller whose surface has been subjected to V-groove processing by iris knurling or the like is manufactured (in this case, the V-groove is 0.1 mm).
It is processed at an angle of about 45 ° with respect to the longitudinal direction of the roller with a pitch of 1 to 0.5 mm. (See FIG. 3 (a)), (ii) The material is coated by a method such as spraying or dipping, and cured (fired) under predetermined conditions (temperature and time) (the thickness of the applied film is set so that the V groove is completely filled) [see FIG. 3 (b). )], (Iii) The surface of the roller is subsequently cut or polished so that the conductive surface and the dielectric surface are mixed in a sea-island structure (small area), and the conductive portion area is reduced to 20 to 60% [ See FIG. 3 (c)].

In addition, (iv) a conductive adhesive (epoxy, polyimide, phenolic, polyester-based resin and conductive filler such as Ag, Au, Cu, Ni,
Ag plated Cu, Ag plated glass, carbon black, etc.
Is added, and the above-mentioned conductive metal particles are buried [see FIG. 4 (a)], (v) and then a dielectric material is coated by a method such as spraying or dipping, and The dielectric part is formed by curing or drying temperature and time [see; FIG. 4 (b)], and (vi) the surface of the roller is subsequently cut or polished so that the conductive surface and the dielectric surface have a sea-island structure (small area). It is also possible to adopt a method of shaving the mixture so that the area of the conductive portion becomes 20 to 60% [see FIG. 4 (c)].

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to examples. Parts represent parts by weight.

Example 1 A developer carrier (developing roller) was manufactured in the following manner.

(I) A V-groove was provided on the surface of a metal roller (φ25) by iris knurling. The V-groove was formed at a pitch of 0.2 mm, and was machined at about 45 degrees with respect to the longitudinal direction of the roller.

(Ii) Polytetrafluoroethylene (trade name: Polyflon TFE M-5; manufactured by Daikin Industries, Ltd.) was electrostatically coated on the surface of the V-grooved metal roller, and then fired at 350 ° C. for about 1 hour. The thickness of the coating film was such that the V-groove was completely filled.

(Iii) The surface of the roller was polished so that the conductive surface and the dielectric surface were mixed in a sea-island structure (small area) so that the conductive part area was about 50%.

Example 2 Conductive adhesive Resin: Trade name DOTITE D-550, conductive particles made by Fujikura Kasei Co., Ltd. Conductive particles Cu particles (particle diameter: 300 μm) Dielectric material Fluororesin (trade name: Lumiflon LF200; manufactured by Asahi Glass Co., Ltd.) A developer carrier (developing roller) was produced in the following manner.

(A) After applying the conductive adhesive on a SUS roller, the conductive particles are embedded on the roller.

(B) Next, the surface of the embedded roller was spray-coated with the dielectric material and cured at 100 ° C. for 1 hour. The coating thickness was such that the conductive particles were completely buried.

(C) The surface of the roller was polished, and the conductive surface and the dielectric surface were mixed in a very small area, and the area of the conductive portion was set to 50%.

Evaluation Each developing roller was mounted on the developing device shown in FIG.
The charge amount of the toner, the amount of toner adhesion, and the toner filming property were measured. Table 1 shows the results.

In the developing device, the toner layer thickness regulating member was made of urethane rubber, the toner supply member was made of conductive urethane sponge, and the toner was charged with positively charged toner.

The toner filming property is obtained by evaluating the toner adhesion state on the surface of the developing roller after 72 hours using the above-described developing device according to the following criteria.

Rank: The toner on the roller surface can be easily wiped off with a cloth or the like.

Rank: Slight toner remains after wiping.

Rank: Completely not wiped off, leaving a thin layer of toner.

Rank: The toner in the molten state is strongly fixed to the roller surface.

From the results shown in Table 1, it can be seen that, with the developing roller of the present invention, toner filming is prevented and sufficient toner charge and adhesion can be obtained.

〔The invention's effect〕

The developer carrier of the present invention has a structure in which a dielectric part and a conductor part are mixed in a sea-island structure on the surface thereof, and the dielectric part contains a substance which is non-adhesive to toner. Therefore, by selectively retaining charges on the surface of the developer carrying member, a large number of minute closed electric fields are formed near the surface of the developer carrying member. Accordingly, a non-magnetic one-component developer composed of a toner externally added with an auxiliary agent is supplied, and the developer is carried on the surface of the developer carrier by the minute closed electric field, and the electrostatic latent image is formed by the carried developer. When the developer carrying member of the present invention is used in an image forming method for visualizing an image, toner filming is prevented, and a large amount of a sufficiently charged nonmagnetic one-component developer is carried on the developer carrying member. To the development area to produce high-density, high-quality images. It can be obtained by constant.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view centering on a developer carrying portion showing an example of a developing device in which a microfield electric field is formed on a developer carrying member useful for carrying out the present invention. Also,
FIG. 2 is a schematic cross-sectional view for explaining a state where a closed electric field is generated by a microfield on a developer carrier in the apparatus shown in FIG. Further, FIGS. 3 (a) to (c) and FIGS. 4 (a) to (c)
FIG. 3 is a schematic cross-sectional view illustrating a surface state in a process of manufacturing the developer carrier of 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.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Koji Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Hiroshi Takashima 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Yuichi Ueno 1-3-6 Nakamagome, Ota-ku, Tokyo Co., Ltd. Inside Ricoh Co., Ltd. (72) Shigekazu Enomoto 1-3-6 Nakamagome, Ota-ku, Tokyo Co., Ltd. (56) References JP-A-55-62469 (JP, A) JP-A-60-54150 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 15 / 08

Claims (3)

(57) [Claims] 1. A developer carrying member in which a dielectric portion and a conductor portion are distributed on a surface, and a dielectric portion is frictionally charged by a toner supply member to selectively form a dielectric portion on a surface of the developer carrying member. By holding the electric charge, a large number of minute closed electric fields are formed near the surface of the developer carrying member, and on this developer carrying member,
If necessary, a non-magnetic one-component developer composed of a toner externally added with an auxiliary agent is supplied by a toner supply member in contact with the developer carrier, and the developer is carried by the developer carrier by the minute closed electric field. A developer carrier used for an image forming method carried on a surface and visualizing an electrostatic latent image with the carried developer, wherein a dielectric portion and a conductor portion are formed on at least the surface thereof, and A developer carrier, wherein the body contains a substance that is non-adhesive to toner. 2. A developer carrying member in which a dielectric portion and a conductor portion are distributed on a surface, and a dielectric portion is frictionally charged by a toner supply member to selectively form a conductive material on the surface of the developer carrying member. By holding the electric charge, a large number of minute closed electric fields are formed near the surface of the developer carrying member, and on this developer carrying member,
If necessary, a non-magnetic one-component developer composed of a toner externally added with an auxiliary agent is supplied by a toner supply member in contact with the developer carrier, and the developer is carried by the developer carrier by the minute closed electric field. A developer carrier for use in an image forming method in which an electrostatic latent image is visualized by using the carried developer on a surface thereof, wherein a dielectric portion and a conductor portion have a sea-island structure on at least the surface thereof. And a dielectric portion corresponding to the sea portion contains a substance which is non-adhesive to the toner. 3. An electrostatic latent image carrier carrying an electrostatic latent image and a developer carrier carrying a developer are opposed to each other in a developing section, and the electrostatic latent image is transferred to the developer in the developing section. In the developing device for visualizing the image, the developer carrier has a dielectric portion and a conductor portion, or the dielectric portion and the conductor portion are formed in a sea-island structure, and the dielectric portion or the sea portion is formed. The dielectric portion corresponding to the portion contains a substance that is non-adhesive to the toner, and the dielectric portion is frictionally charged by the toner supply member to hold the charge, and the conductive portion is separated from the dielectric portion. Is charged in an amount opposite to the charge and in an amount corresponding to the charge by electrostatic induction generated in response to the charge of the developer, thereby forming a charge arrangement on the surface of the phenomenon agent carrier, and a large number of micro-closes are formed between the charges. Remove the auxiliary agent, if necessary, from the surface of the developer carrier where the electric field is formed. Developing device and the non-magnetic one-component developer consisting of toner supplied by the toner supply member which abuts against the developer carrying member was, characterized by holding the developer charged by the micro 閉電 field.