JPH07219334A - Developing device - Google Patents

Abstract

PURPOSE:To obtain enough electrification property for toner and to improve contamination of the base, afterimage and electrification stability in a device to develop an electrostatic latent image with a developer carrier having a thin layer of a nonmagnetic one-component toner formed on the surface by a thin layer forming member. CONSTITUTION:This developing device is equipped with a developer carrier 20 at least the surface of which has imidazole or imidazole deriv. It is preferable that the surface of the developer carrier 20 consists of at least a polymer and imidazole or imidazole deriv. and the amt. of imidazole or imidazole deriv. is 1-60 pts.wt. to 100 pts.wt. of the polymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for developing an electrostatic latent image on an electrostatic latent image carrier such as an electronic copying machine, a printer or a facsimile by a non-magnetic one-component developing method. Is a developer carrier that is driven to rotate,
If necessary, a non-magnetic one-component developer (toner) to which an auxiliary agent is externally added is supplied, and the developer is carried on the surface of the developer carrier and conveyed. The present invention relates to a developer carrier for developing an electrostatic latent image into a visible image in a developing area where the carrier faces each other.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electronic copying machine, a printer or a facsimile machine, which forms an electrostatic latent image on a latent image carrier and visualizes it with a developer to obtain a recorded image, A dry type developing device using a developer is widely adopted. Known two-component developer having a toner and a carrier and one-component developer containing no carrier are known as the powdery developer. The former two-component developing method using the two-component developer gives a relatively stable and good recorded image, but on the other hand, deterioration of the carrier and variation of the mixing ratio of the toner and the carrier are likely to occur during repeated use. There is a drawback that the maintenance of the device is complicated and the structure of the entire device becomes large. From such a viewpoint, a one-component developing method using a one-component developer which does not have the above-mentioned drawbacks has been receiving attention. The one-component type developer includes one consisting of only a toner and one obtained by mixing a toner to which an auxiliary agent is externally added as necessary and an 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 powder. Here, since the magnetic substance is generally opaque, when a color image including full color and multi-color is formed by magnetic toner, the developed visible image becomes unclear, and a vivid color image cannot be obtained. Therefore, especially for color development, it is desirable to adopt the one-component development method using non-magnetic toner.

By the way, in the developing system adopting the one-component developing system, the one-component type developer is carried on a developer carrier and conveyed, and the developer carrier and the latent image carrier are opposed to each other. In the area, the electrostatic latent image formed on the latent image carrier is visualized by a developer, but in order to form a high-quality visible image with a predetermined density, a large amount of sufficiently charged toner is used. It is necessary to convey the latent image to a visible image by transporting it to the developing area. When magnetic toner is used, the above-mentioned requirements can be satisfied relatively easily because the one-component developer can be carried on the carrier by utilizing the magnetic force of the magnet provided inside the developer carrier. Is. However, when a non-magnetic one-component developer is used, it cannot be carried on the developer carrying member by magnetic force, so that it is difficult to satisfy the above-mentioned requirements. Various countermeasures against this have been proposed in the past, for example, JP-A-61-161.
In Japanese Patent No. 42672, a dielectric (insulator) layer is laminated on the surface of a developer carrying member (developing roller), and a developing member composed of, for example, a sponge roller is pressure-bonded to the two layers, While frictionally charging the opposite polarities,
A method has been proposed in which a non-magnetic toner charged to the opposite polarity to the dielectric is electrostatically attached to the dielectric and the one-component developer is conveyed to the developing area.

A configuration is also known in which an electric field is applied between the developing roller and the developer supplying member in a direction in which the non-magnetic toner is electrostatically transferred to the developing roller side, but such a configuration is added. However, it is difficult to attach a sufficient amount of toner to the developing roller. Further, in a developing device using a non-magnetic one-component developer, a sponge roller in JP-A-60-229057, an elastic roller in JP-A-62-229060, a fur brush in JP-A-6l-52663, and the like. The toner is charged by frictional charging between the toner and the replenishing member, and the toner is electrostatically attached to the developing roller by friction during contact with the developing roller. Further, a thin film forming member such as a blade is used. , A method of controlling a toner layer to develop a latent image on a photoreceptor has been proposed.

As the material of the developing roller, various materials such as an insulating material, a medium resistance material, and a laminated material are used. For example, an insulating coated roller (Japanese Patent Laid-Open No. 55-467)
No. 68), a roller coated with a medium resistor (Japanese Patent Laid-Open No. 58-13)
No. 278) and an electrode roller having an insulator and a conductive surface (JP-A-53-36245). Further, as a toner supply member, 10 ² to 10 ⁶ Ω ・
cm conductive foam (JP-A-60-229057), an elastic body with a skin layer (JP-A-60-229060), a fur brush (JP-A-61-42672), and the like. And a metal body having irregularities on the surface as a developing roller (JP-A-60-5).
No. 3976). According to the method shown in these references, the toner is adhered to the developing roller by frictional electrification between the developing roller and the toner. No charged toner adhesion can be obtained. The fully charged toner charge amount (for negatively charged toner) is −15 to −30.
It means a range of about μc / g. Further, even if a high toner charge amount is obtained, problems such as a background stain defect due to generation of reversely charged toner, an afterimage due to insufficient toner replenishment property, and charging stability occur. There is a proposal to improve the chargeability of toner by incorporating a material for imparting toner charge to the developing roller material (Japanese Patent Publication No. 5-77070, etc.). However, these problems have not been fully resolved.

[0006]

An object of the present invention is to provide a developer (toner) used for developing non-magnetic one-component toner,
It is an object of the present invention to provide a developing device which can provide sufficient toner chargeability and can improve background stains, afterimages, charge stability and the like during development.

[0007]

According to the present invention, there is provided an apparatus for developing an electrostatic latent image by a developer carrier having a thin layer of a non-magnetic one-component toner formed on the surface thereof by a thin layer forming member. Provided is a developing device, wherein the agent carrier has imidazole or an imidazole derivative on at least the surface thereof. According to the invention, the surface of the developer carrier is composed of at least a polymer and an imidazole or an imidazole derivative, and the content of the imidazole or the imidazole derivative is preferably 1 to 60 parts by weight with respect to 100 parts by weight of the polymer. A developing device is provided.

In the present invention, imidazole is used as the substance forming the surface of the developer carrying member, but an imidazole derivative can also be used. Examples of the imidazole derivative include imidazole alkyl derivatives, aryl derivatives, halogen derivatives, halogenated alkyl derivatives, oxyalkyl derivatives, nitro derivatives, amino derivatives, aldehyde derivatives, ketone derivatives, mercapto derivatives, carboxylic acid derivatives and sulfonic acid derivatives. Furthermore, the following are mentioned as a specific example of those imidazole derivatives.

That is, as the alkyl derivative, 2-methylimidazole, 2-ethyl-4-methylimidazole, 1,4,5-trimethylimidazole, etc., and as the aryl derivative, 2-phenylimidazole, 2,4
-Diphenylimidazole or the like, halogen derivatives such as 2-bromoimidazole and 4,5-dibromoimidazole, and halogenated alkyl derivatives such as 4-
Chloromethylimidazole and the like include 2-oxymethylimidazole and 4- (β- as oxyalkyl derivatives.
(Oxymethyl) imidazole, etc., as the nitro derivative, 4-nitroimidazole, etc., as the amino derivative, 2-aminoimidazole, 4-aminomethylimidazole, etc., and as the aldehyde derivative, 4-imidazole aldehyde, etc. As the derivative, 2-imidazole phenyl ketone, etc., as the mercapto derivative, 2-methylcaptoimidazole, etc., as the carboxylic acid derivative, 2-imidazole carboxylic acid, etc., and as the sulfonic acid derivative, 2-imidazole sulfonic acid, etc. Can be mentioned.

Further, as a derivative having a plurality of different groups, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2-phenyl-4-methyl-5-hydroxyimidazole, 2-bromo-4. Examples include various compounds such as -methylimidazole and 2-phenyl-4-methyl-5-oxymethylmethylimidazole. It is also possible to use a plurality of these imidazoles or simultaneously.

The imidazole or imidazole derivative which is particularly preferably used in the present invention is imidazole or 2
Alkyl derivatives of imidazole such as -ethyl-4-methylimidazole, aryl derivatives such as 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1
-A derivative having a plurality of different groups such as benzyl-2-methylimidazole.

These compounds can be added to a polymer such as resin or rubber, if necessary, and processed into a developer carrier having a predetermined shape by a conventional method. By adding it to the polymer, it is possible to improve various properties such as surface releasability, abrasion resistance and mechanical properties.

As the polymer, a usual and general one can be used. Specific examples thereof include the following organic polymers. That is, vinyl-based resins such as polyvinyl chloride, polyvinyl butyral, polyvinyl alcohol, polyvinylidene chloride, polyvinyl acetate, polyvinyl formal; polystyrene-based resins such as polystyrene, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer, etc. Polyethylene resins such as polyethylene and ethylene-vinyl acetate copolymers; acrylic resins such as polymethyl methacrylate and polymethyl methacrylate-styrene copolymers; polyacetals
Resin materials such as polyamide, cellulose, polycarbonate, phenoxy resin, polyester, fluororesin, polyurethane, phenol resin, urea resin, melamine resin, epoxy resin, unsaturated polyester resin, silicone resin, modified 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, fluorine rubber, silicone-modified ethylene-propylene rubber Rubber material etc.

The method of adding imidazole or imidazole derivative to these polymers is, for example, using a kneading device such as a two-roll or kneader, at room temperature or by heating and melting to knead, or the polymer and imidazole or imidazole derivative can be dissolved. There are methods such as dissolving or dispersing in a solvent. The amount of imidazole or imidazole derivative added to the polymer is 100
1 to 60 parts by weight is preferable with respect to parts by weight. A particularly preferred range is 5 to 50 parts by weight. If the addition amount is less than 1 part by weight, a sufficient toner charge amount cannot be obtained, and if it exceeds 60 parts by weight, the toner chargeability is adversely deteriorated and the surface characteristics such as surface releasability and abrasion property are impaired. These kneaded materials and coating liquids can be processed and molded on the surface of the developer carrying member by using a usual processing method. As the molding method, for example, press molding, steam molding, extrusion molding, spray coat dipping and the like are used.

The structure of the developer carrying member of the present invention is preferably a cylindrical sleeve, and at least the surface of the cylindrical supporting member is preferably conductive (preferably, the surface is more preferably smooth). It is sufficient that the imidazole derivative is contained, and the layer containing the imidazole derivative may have any layer structure such as a single layer or multiple layers, and electrical characteristics such as insulation and conductivity. The cylindrical support may be a metal drum such as SUS or aluminum, or a glass or plastic tube whose surface is electrically conductive.

Next, a typical developing device using the developer carrying member of the present invention will be described. FIG. 1 is a schematic diagram centering on a developer carrier portion of a typical developing device of the present invention. In FIG. 1, the toner 60 contained in the toner tank 70 is forced to the toner supply member (sponge roller) 40 by the stirring blade (toner supply auxiliary member) 50, and the toner 60 is supplied to the toner supply member 40. To be done. On the other hand, the developer carrying member (developing roller) 20 of the present invention, which has completed development, rotates in the direction of the arrow (for example, 400 rp).
m), and reaches the contact portion with the toner supply member 40. The toner supply member 40 rotates in the opposite direction to the developer carrying member 20 (for example, 300 rpm), charges the developer carrying member 20 and the toner 60, and attaches the toner 60 onto the developer carrying member 20. Further, the developer carrying member 20 rotates, and the toner adhered on the developer carrying member 20 is stabilized in charge while the thickness is regulated by the toner thin layer forming member (elastic blade) 30, so that the developing area 80 is formed. Reach In the developing area 80,
The latent image is developed by contact or non-contact development. Here, if necessary, the developer carrier 20, the toner supply member 40
An optimum image can be controlled by applying a bias such as direct current, alternating current, direct current superposed alternating current, and pulse to the.

[0017]

The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

Example 1 2-Phenylimidazole 1
g was ultrasonically dissolved in 10 g of ethanol to obtain a coating liquid. This is spray-coated on a 16φSUS core,
It was dried at 150 ° C. for 1 hour to obtain a developer carrying member (developing roller) having a coating film with a thickness of 25 μm.

[Examples 2 to 8] With respect to 100 parts by weight of an acrylic-modified silicone resin (KR9706; Shin-Etsu Chemical Co., Ltd.), an additive compound was made to correspond to Examples 2 to 8 as shown in Table 1 below. A predetermined amount was added to each. This one
6φSUS cored bar is spray coated and 200 ℃ 30
After curing and drying, a developer carrier was obtained. The coating film is 2
It was 5 μm thick.

[0020]

[Table 1]

[Comparative Example 1] A core of 16φSUS was used as a developer carrying member without any treatment.

The developer carrying members of Examples 1 to 8 and Comparative Example 1 described above were mounted on the developing device shown in FIG. 1, and the toner charge amount and the toner adhesion on the developer carrying member were set under the following conditions. The quantity was measured.

Members of developing device Negatively charged toner (7.5 μm) Epoxy resin 100 parts by weight Salicylic acid derivative zinc salt 4 parts by weight Copper phthalocyanine blue pigment 2 parts by weight Hydrophobic silica 8 parts by weight Blade SUS (100 μm thick) Replenishing roller Conductive Urethane sponge

Measurement method Toner charge amount Blow-off method Toner adhesion amount Suction method The results of toner charge amount and adhesion amount of Examples 1 to 8 and Comparative Example 1 are shown in Table 2.

[0025]

[Table 2] It can be seen that the developer carrier of the present invention enables development with a high charge amount and a high toner adhesion amount.

The developer carrier of Examples 1 and 2 was idled for 10 hours using the same developing device and toner, and a test was conducted. Then, the amount of wear of the developer carrier was measured. 5.5 μm in the first embodiment, 10 μm in the second embodiment
It was in a range where there was no problem in practical use.

[Example 9] With respect to 100 parts by weight of an acrylic modified silicone resin (KR9706; Shin-Etsu Chemical Co., Ltd.),
7 parts by weight of 2-ethyl-4-methylimidazole were added. This is spray-coated on a 16φSUS core,
It was cured and dried at 200 ° C. for 30 minutes to obtain a developer carrier. The coating film had a thickness of 25 μm.

[Comparative Example 2 and Comparative Example 3] 100 parts by weight of an acrylic-modified silicone resin (KR9706; Shin-Etsu Chemical Co., Ltd.) was prepared by adding the additive compounds shown in Table 3 below to Comparative Examples 2 and 3. A fixed amount was added. This is 16φ SUS
The core metal was spray-coated and cured and dried at 200 ° C. for 30 minutes to obtain a developer carrier. The coating film had a thickness of 25 μm.

[0029]

[Table 3]

In the developer carrying members of Example 9, Comparative Example 2 and Comparative Example 3, the toner charge amount and the adhered amount were measured in the same manner as described above, and the background stain and toner replenishment of the photosensitive member were conducted by the following methods. Properties, high-temperature high-humidity (30 ° C./90%), low-temperature low-humidity (10 ° C./15%), toner charge amount and adhesion amount were also measured.

Method for measuring background stain on photoconductor Latent image forming conditions Photoconductor; OPC (negative charging) Photoconductor linear velocity; 60 mm / sec Developer carrier linear velocity; 90 mm / sec Photoconductor background stain measurement 0PC potential = -800 V, developer carrier potential = -400
The image density measured with a Macbeth densitometer after developing the photoconductor with V and transferring the developed toner onto the tape,
It was evaluated by the difference (ΔID) from the image density of the untransferred tape.

Toner replenishment property and toner rising property measurement method OPC potential = -200 V, developer carrier potential = -400
Under the developing condition of V, the charge amount of the development toner on the OPC at the 1st rotation of the developing roller and the 0th rotation of the developer carrying member during continuous development is measured by the blowoff method, and the adhesion amount is measured by the suction method, and calculated by the following formula. did. Toner replenishability = [adhesion amount (10 revolutions) / adhesion amount (1 revolution)]
× 100 (%) Toner rising property = [charge amount (10 rotations) / charge amount (1 rotation)] × 100 (%) The results obtained by the developer carrying members of Example 9, Comparative Example 2 and Comparative Example 3 are shown in Table 4. Shown in.

[0033]

[Table 4]

It can be seen that the developer carrier of the present invention is excellent not only in toner charging property and toner adhesion property but also in toner rising property and environmental stability.

[0035]

In an apparatus for developing an electrostatic latent image by a developer carrier having a thin layer of non-magnetic one-component toner formed on the surface by a thin layer forming member, the developer carrier has at least the surface thereof an imidazole or an imidazole derivative. (At this time, the surface of the developer carrier is composed of at least a polymer and an imidazole or an imidazole derivative, and the content of the imidazole or the imidazole derivative is 1 to 60 parts by weight with respect to 100 parts by weight of the polymer. Is preferable), it is possible to obtain a sufficient toner chargeability. Further, it is possible to improve the background stain, the afterimage, and the charging stability.

[Brief description of drawings]

FIG. 1 is a schematic diagram centering on a developer carrier portion of a typical developing device of the present invention.

[Explanation of symbols]

10 ... Photosensitive member, 20 ... Developer carrying member, 30 ... Thin layer forming member, 40 ... Toner supply member, 50 ... Stirring blade, 60 ... Toner, 70 ... Toner tank, 80 ...
Development area

Claims (2)

[Claims] 1. An apparatus for developing an electrostatic latent image by a developer carrier having a thin layer of non-magnetic one-component toner formed on the surface by a thin layer forming member, wherein the developer carrier has at least the surface thereof imidazole or imidazole. A developing device having a derivative. 2. The surface of the developer carrier is composed of at least a polymer and an imidazole or an imidazole derivative, and the content of the imidazole or the imidazole derivative is 1 to 100 parts by weight of the polymer.
The developing device according to claim 1, wherein the developing device is 60 parts by weight.