JPH0695243B2 - One-component developing device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-component developing device for converting an electrostatic latent image into a visible image by a one-component developer in an electrophotographic copying machine, an electrostatic printer, etc., more specifically, The present invention relates to a charge control member which forms a thin layer of a developer on a developer carrier and imparts a suitable charge to the developer.

2. Description of the Related Art As a developing device in a conventional electrophotographic copying machine or the like, a developing device employing a cascade developing method, a magnetic brush developing method, a liquid developing method, or the like is widely known. In the developing device adopting these developing methods, it is necessary to replace the developer regularly, so that much work time and labor are spent because maintenance is frequently performed.

In recent years, a one-component developing method without a carrier and a magnetic roll has come to be used as a developing method for the purpose of reducing the frequency of exchanging the developer. Further, among them, a non-magnetic developer is adopted because of its high transparency, and it is applied to color development with good results.

As this non-magnetic one-component developing method, US Pat.
As disclosed in No. 7, the "touch-down developing method" is generally well known, and in this developing method, a discharge action by a corotron is used as a means for giving an electric charge to a developer. Although this touch-down developing method is convenient, it has many drawbacks in terms of work, such as a large apparatus or periodic cleaning of the colontron wire.

Further, JP-A-47-13088 and JP-A-47-13089 disclose inventions relating to impression development and a toner distribution process suitable for impression development. Impression development consists of a pressure developing drum that carries toner and conveys it to the photoconductive material, a toner distribution blade, etc.The pressure developing drum rotates and the toner flowing under the toner distribution blade is triboelectrically charged by contact with the blade. A uniform layer is formed and contacts the photoconductive material to selectively transfer it to the electrostatic latent image. The toner distribution blade is a doctor blade made of polytetrafluoroethylene or the like having a circular tip, and one to three of these are used. On the other hand, the pressure developing surface is formed of, for example, resin-graphite, and the lower layer thereof has a flexible conductor and an elastic backing material.

However, even in such a constitution, in order to obtain a higher quality copy image, it is necessary to form a uniform and thin layer of toner on the surface of the pressure-developed image and impart an appropriate charge to the toner.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, according to the conventional one-component developing device, a charge having a desired polarity is applied to the developer by bringing the charge control member into contact with the developer carrying member. Since the friction time is relatively short, a sufficient charge amount of the developer cannot be obtained, and a so-called "fogging" copy image in which the developer is attached to the non-image portion of the electrostatic latent image holding member is generated.

In addition, because the developer cannot be sufficiently charged, the developer is not sufficiently electrostatically carried on the developer carrier due to the stress of the charge control member, and the thin layer of the developer becomes uneven. However, there is a problem in that the developer spills from the developer carrier and contaminates the periphery of the developing device.

An object of the present invention is to solve the above-mentioned problems and to form a uniform developer thin layer having a predetermined thickness by giving sufficient charge to a developer formed as a thin layer on a developer carrier. It is to find a means to do so to obtain a uniform visible image with less fog on the electrostatic latent image holder.

Means for Solving the Problems In order to solve the conventional problems, in the one-component developing device of the present invention, a charge restraining member is brought into contact with a developer carrying member that supplies the developer to the electrostatic latent image holding member. A predetermined charge is applied to the developer by the charging control member to form a thin layer of the developer on the developer carrying member, and the thin layer of the developer is applied to the electrostatic latent image holding member. In the one-component developing device for selectively applying and developing according to the above, the charge restricting member is configured by including 0.1 to 60% by weight of vanadium pentoxide in the rubber base material.

According to a preferred embodiment of the present invention, the charge restricting member comprises an elastic body attached to the main body of the developing device and a soft elastic body that abuts on the peripheral surface of the developer carrying body at the tip of the elastic body. A base material whose elastic body is made of silicone rubber or the like contains vanadium pentoxide V ₂ O ₅ in an amount of 0.1 to 60% by weight.
As the elastic body, it is desirable to use a leaf spring material made of phosphor bronze, silicon steel, stainless steel or the like and having a thickness of 0.03 to 0.5 mm. Examples of the base material of the soft elastic body include silicone rubber, ethylene propylene rubber, styrene butadiene rubber, epichlorovidrin rubber, chloroprene rubber and butyl rubber.
It is desirable to use JIS standard rubber hardness of 10 to 70 degrees. Further, vanadium pentoxide V ₂ O ₅ having an electronegativity Xi of a metal ion of 10 or more is contained in the base material in an amount of preferably 0.1 to 60% by weight, more preferably 0.2 to 25% by weight.

A desirable one-component developing device to which the present invention is applied is configured as shown in FIG. 1 and FIG. 2. First, the developer 2 in the hopper 1 is fed onto the developer feeding member 3 by gravity,
The developer is triboelectrically charged by rubbing the developer supply member 3 and the developer carrying member 4, and then the developer is transferred to the charge regulating member 5, where a sufficient uniform charge is applied to the developer. At the same time, by forming a uniform thin developer layer on the developer carrying member 4, this thin developer layer flies to the electrostatic latent image in the developing area facing the electrostatic latent image holding member 6, and The electrostatic latent image is made visible.

The developer supplying member 3 is formed by adhering an ethylene propylene dimaterial (EPDM) rubber layer to the outer circumference of a stainless steel cored bar, and rotates while being in pressure contact with the peripheral surface of the developer carrying member 4. The developer carrying member 4 is formed by coating the surface of a solid or hollow cylindrical member made of iron with a semiconductive resin having a specific resistance of 10 ⁶ to 10 ¹² Ω · cm, for example, a phenol resin to a thickness of 1 mm. The charge restricting member 5 is composed of an elastic body 8 and a soft elastic body 9 made of the above-mentioned materials as shown in FIG. 2, and the elastic body 8 made of, for example, a leaf spring material having a thickness of 0.1 mm has the above-mentioned soft elasticity. It is configured by adhering the body 9.

Then, the developer 2 in the hopper 1 becomes the developer supply member 3
After being frictionally charged by the rubbing between the developer carrier 4 and the developer carrier 4 to give an electric charge, it is transferred to the charge regulating member 5 while adhering on the developer carrier 4, and is charged by the charge regulating member 5 to a predetermined thickness. The charge regulating member 5 is formed on the thin developer layer.
Gives a sufficient electric charge having a predetermined polarity.

The thin developer layer is sent to the electrostatic latent image holding member 6 by rotating the developer holding member 4 while applying a DC bias AC bias voltage to the developer holding member 4, and the electrostatic latent image holding member 6 is transferred. The electrostatic latent image flies toward the electrostatic latent image by the electric field between the electrostatic latent image and the developer carrying member 5, and is selectively attached to the electrostatic latent image to form the visible image. To

Operation According to the present invention, the charging control member is constituted by the rubber base material containing vanadium pentoxide V ₂ O ₅ in an amount of 0.1 to 60% by weight. Therefore, the charging control member is shown in FIG. As is clear from the experimental results, it is possible to impart a sufficient charge to the developer carried on the developer carrier.

When such a thin layer of sufficiently charged developer faces the development area of the electrostatic latent image carrier, an appropriate amount of the developer is discharged according to the electrostatic latent image on the electrostatic latent image carrier. Attached on the latent image,
When unnecessary development agent does not adhere to the non-image area on the electrostatic latent image holding member and the development is transferred onto the sheet, a clear copy image with less fog can be obtained. In addition, since a thin developer layer is formed on the developer carrier with a relatively strong adsorption force while the charge restricting member imparts sufficient charge to the developer, the developer spills around the developing device and stains the surroundings. There is no worry.

Generally, it is sufficient that the developer carrying member and the charge restricting member are separated from each other with respect to the toner with respect to the triboelectric charging order, and the developer carrying member is higher than the charge restricting member. Further, there is a force that the toner physically adheres to the developer carrying member regardless of frictional charging with the developer carrying member.

In the present invention, the most excellent toner layer is formed when a toner containing a semiconductive phenol resin and a metal oxide is used as the surface layer of the developer carrier, and a copy image of high quality is obtained. It was Further, in the present invention, similarly good results are obtained regardless of whether the toner is non-magnetic or magnetic.

Some examples of the present invention will be described below. For Examples 1 to 3, a developing device as shown in FIGS. 1 and 2 was used.

Example 1 In the first example, the elastic body 8 of the charge control member 5 is a leaf spring material made of stainless steel SUS304csp3 / 4H and having a thickness of 0.1 mm.
The soft elastic body 9 is composed of a silicone rubber having a JIS rubber hardness of 50 degrees as a base material and containing vanadium pentoxide V ₂ O _{5 in an amount} of 1.0% by weight. As a method of manufacturing the charge restricting member 5, first, a KE650-
U, KE850-U, KE554-U, KE555-U, KE752-U (all manufactured by Shin-Etsu Silicone Co., Ltd.), TSE221, TSE270, TSE2
Thermally vulcanizable silicone rubber such as 60 (all manufactured by Toshiba Silicone Co., Ltd.) is used alone or as a mixture, and V ₂ O ₅ is kneaded into this silicone rubber with a kneader consisting of three rolls.
This is put in a mold, heated and vulcanized, and then cooled to form a rubber. The rubber obtained in this way is cut with a cutter to a thickness of 1 m.
It is cut into m, width 10 mm, and length 300 mm, and the soft elastic body 9 is heated and pressure-bonded to the leaf spring surface of the elastic body 8 using an adhesive.

The charge regulating member 5 including the elastic body 8 and the soft elastic body 9 thus obtained was attached to the developing device shown in FIG. As the developer 2, a positively chargeable toner containing a nigrosine dye and carbon in a styrene acrylic binder was used. The rotation speed of the developer carrier 4 is the peripheral speed.
It was driven at 127 mm / sec.

When the charge amount of the developer layer as a thin layer formed on the developer carrying member 4 by the charge regulating member 5 was measured under the above set conditions, the results shown in FIG. 3 were obtained. In the figure,
A shown by a solid line shows the charging characteristics of Example 1, and B shown by a chain line shows the charging characteristics of a comparative example in which the soft elastic body 9 does not contain V ₂ O ₅ .

As is clear from the graph shown in FIG. 3, the average charge amount of the developer according to the comparative example was 2 μc / gr, whereas the average charge amount of the developer according to the example 1 was 15 μc / gr, which was negative polarity. No developer was produced. As a result of performing the copy test according to the example 1, a clear copy image without fog could be obtained.

Example 2 In the second example, V ₂ O ₅ contained in the soft elastic body 9 was changed from 0 to 80.
Various changes were made up to the weight%. The structure of the elastic body 8, the basic manufacturing method of the soft elastic body 9, the developer, and the like were the same as in Example 1. When the charge amount of the developer charged by the charge restricting member 5 was measured under the same conditions as the setting conditions of Example 1, the average charge amount of the developer was found to vary depending on the V ₂ O ₅ content. It was measured as shown in FIG.

As is clear from the graph in FIG. 4, the content of V ₂ O ₅ is 0.
It has been found that the developer has good charging characteristics in the range of 1 to 60% by weight. As a result of performing the copy test according to the second embodiment, a clear copy image without fog can be obtained.

Example 3 In the third example, ethylene propylene rubber was used as the base material of the soft elastic body 9, and the V ₂ O ₅ content in this was 1.0% by weight, which is the same as in Example 1, and the constitution of the elastic body 8 was The basic manufacturing method of the soft elastic body 9, the developer and the like were the same as in Example 1. When the charge of the developer charged by the charge regulating member 5 was measured under the same setting conditions as in Example 1,
As a comparative example, the developer containing no V ₂ O ₅ had an average charge amount of 3.5 μc / gr, whereas in Example 3 the developer had an average charge amount of 25 μc / gr. As a result of a copy test, a copy image with a large amount of fog was obtained in the comparative example, but a clear copy image without a fog was obtained in Example 3.

Although the non-magnetic one-component developer is used in Examples 1 to 3, the present invention is not limited to this, and it goes without saying that a magnetic one-component developer may be used.

Effects of the Invention According to the present invention, with respect to the developer to be supplied onto the developer carrying member, a sufficient amount of charge is imparted by the charge controlling member made by containing vanadium pentoxide in the rubber base material in an amount of 0.1 to 60% by weight. Since a uniform thin developer layer based on this sufficient charge is formed on the developer carrying member, an appropriate developing density can be obtained according to the electrostatic latent image on the electrostatic latent image holding member. Further, it is possible to prevent the occurrence of fogging that a large amount of developer adheres to the non-image area, and it is possible to obtain a clear copy image.

Further, since the electrostatic attraction of the developer to the developer carrier is strong, it is possible to reliably prevent the developer from spilling and contaminating the surroundings of the developing device.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is a sectional view showing the charge regulating member thereof, and FIG. 3 is a charging characteristic of each developer of an embodiment of the present invention and a comparative example. FIG. 4 is a charging characteristic diagram showing the charging characteristic, and FIG. 4 is a charging characteristic diagram showing the charging characteristic of the developer in the embodiment of the invention. 1 ... Bopper, 2 ... Developer, 3 ... Developer supply member, 4 ... Developer carrier, 5 ... Charge regulating member, 6 ... Electrostatic latent image holder, 8 ... Elastic body, 9 ... Soft elastic body.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobuo Hyakutake 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Zero Tux Co., Ltd.Ebina Business Office (72) Inventor Takashi Yamamuro 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Zero Tux Co., Ltd.Ebina Business In-house (72) Inventor Masatsugu Kajimoto 2274 Hongo, Ebina-shi, Kanagawa Fuji Zero Tsux Co., Ltd.Ebina business office (72) Inventor Hideki Tachibana 2274, Hongo, Ebina-shi, Kanagawa Fuji Zero Tux Co., Ltd.Ebina business office (72) Invention Person Junichi Hama 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Zero Tux Co., Ltd., Ebina Business Office (72) Inventor Kazuhiko Tsukakoshi 2274 Hongo, Ebina City, Kanagawa Prefecture Ebina Business Office, Fuji Zero Tsuxu Co., Ltd. (56) Reference JP-A-58- 93067 (JP, A) JP 60-3656 (JP, A) JP 60-111268 (JP, A) JP 60-113248 (JP, A) JP 59-174861 (JP, A)

Claims (1)

[Claims] 1. A charge control member is brought into contact with a developer carrying member for supplying the developer to the electrostatic latent image holding member, and a predetermined charge is applied to the developer by the charge restricting member, so that the developer is carried on the developer carrying member. In a one-component developing device for forming a thin layer of a developer and selectively applying the developer of the thin layer in accordance with an electrostatic latent image on an electrostatic latent image carrier to develop, A one-component developing device comprising a rubber base material containing 0.1 to 60% by weight of vanadium pentoxide.