JP3115056B2 - Developing device - Google Patents

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 supplying a one-component developer to a rotatably driven developer carrier, carrying the developer on the surface of the developer carrier, and transporting the developer. An electrostatic latent image formed on the latent image carrier is visualized by the developer carried on the developer carrier in a development region where the developer and the developer carrier are opposed to each other; The present invention relates to an image developing device.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electronic copying machine, a printer, or a facsimile, which forms a latent image on a latent image carrier and visualizes the latent image with a developer to obtain a recorded image, a powdery image is formed. Dry developing devices using a developer are 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 been attracting attention. One-component developer is composed of only toner,
There is a mixture of a toner and an auxiliary agent to which an auxiliary agent is externally added as necessary. 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.

[0003]

The functions required of such a non-magnetic one-component developing device include, for example, electric characteristics for obtaining desired developing characteristics, toner charging properties (charging amount and adhesion amount of toner on a developing roller), and toner. Filming properties Wear resistance Low torque (coefficient of friction) Physical environment, stability over time, etc. It is difficult to fully satisfy these functions with a developing device using a single layer of developer carrier using a single material. The device was used. However, a developing device equipped with the plurality of developer carriers has a very large number of manufacturing steps and is costly. Therefore, a low-cost and multifunctional developer carrier has been desired.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a developing device equipped with a specific developer carrier is suitable for the above purpose. That is, according to the present invention, the developer carrier is composed of a continuous phase polymer and a discontinuous phase polymer.
And a discontinuous phase polymer
The triboelectric phase is triboelectrically charged and selected on the surface of the developer carrier.
By holding the electric charge, the developer
A number of micro-closed electric fields are formed beside the developer carrier.
To supply a non-magnetic one-component toner,
The developer is carried on the surface of the developer carrying member,
Used in image forming methods for visualizing electrostatic latent images with
An image carrier , wherein at least the surface of the developer carrier is blended with two or more different amorphous polymers and then molded to form a continuous phase (sea part) and a discontinuous phase (island part) There developing device of an electrostatic latent image, characterized in that the configuration is provided by being formed.

[0005] The developing device of the present invention has the above-mentioned structure,
Since a developer carrier having a plurality of polymers exposed on the surface is used, they complement various characteristics, so that balanced roller characteristics can be obtained. In addition, since the developer carrier can be easily prepared, the cost can be reduced.

Hereinafter, such a developing device will be described.
FIG. 1 shows an outline of a representative developing device of the present invention, focusing on a developer carrier. In FIG. 1, the toner tank 70
Is forcibly brought 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. On the other hand, the developer carrier (developing roller) 20 that has completed the development rotates in the direction of the arrow (for example, 400 rpm) and reaches a contact portion with the toner supply member 40. The toner supply member 40 rotates in the opposite direction (for example, 300 rpm) to the developer carrier 20, charges the developer carrier 20 and the toner 60, and causes the toner 60 to adhere to the developer carrier 20. Further, the developer carrier 20 rotates, and the toner adhered on the developer carrier 20 is regulated in thickness by the toner layer thickness regulating member (elastic blade) 30 while its charge is stabilized, and reaches the developing area 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, direct current heavy alternating current, or pulse can be applied to the developer carrier 20 and the toner supply member 40 to control an optimal image.

Next, the developer carrier of the present invention will be described. As described above, the developer carrier of the present invention has a sea-island structure composed of a continuous phase (sea portion) and a discontinuous phase (island portion) by blending two or more different amorphous polymers and then molding. Has become. What is expressed as an amorphous polymer here can be amorphous or flowable at least by heat and pressure during molding, and may have a continuous phase or discontinuity after molding due to a difference in affinity and compatibility with other polymers. It can take the form of a phase and is generally classified into what is called a polymer alloy. Therefore, the method of dispersing the thermoset particles in the continuous phase material and molding them, or the method of dispersing the thermoplastic particles in the continuous phase material and molding them at a temperature equal to or lower than the melting temperature of the particles is included in this category. Absent. Since the developer carrier used in the present invention does not produce particles in advance in this way or compound it with other materials,
A non-uniform structure composed of a continuous phase and a discontinuous phase can be provided on the surface of the carrier at low cost, and multifunctionality of the developer carrier can be achieved by combining various materials.

FIG. 2 shows the most typical example of the developer carrier of the present invention. The discontinuous phase exists independently as an island in the continuous phase of the marine part. It is possible to tune the characteristics of the developer carrier by the surface occupied area and diameter of the discontinuous phase. The surface occupied area of the discontinuous phase can be adjusted by the ratio of the polymer of the discontinuous phase to the polymer of the continuous phase. Discontinuous phase polymer / continuous phase polymer = 10/90 to 90/10 (volume ratio)
Is preferable. If it exceeds this range, the properties of each polymer are hardly exhibited. Discontinuous phase diameter (average) is 1 μm
~ 500 µm is preferred. If it is less than 1 μm, it is difficult to obtain the characteristics as a discontinuous phase, and if it exceeds 500 μm, the strength of the developer carrying member is reduced due to the compatibility problem between the continuous phase and the discontinuous phase, and the surface has scratches, cracks and cracks. And so on.

Polymers for forming the developer carrier used in the present invention include a resin material (plastomer) and a rubber material (elastomer), and specific examples thereof include the following. Vinyl resins such as polyvinyl chloride, polyvinyl butyral, polyvinyl alcohol, polyvinylidene chloride, polyvinyl acetate, and polyvinyl formal; polystyrene resins such as polystyrene, styrene-polyacrylonitrile copolymer, and acrylonitrile-butadiene-styrene copolymer A polyethylene resin such as polyethylene and ethylene-vinyl acetate copolymer; polymethyl methacrylate, polymethyl methacrylate;
Acrylic resins such as styrene copolymers; resins such as polyacetal, polyamide, cellulose, polycarbonate, phenoxy resin, polyester, fluororesin, polyurethane, phenolic resin, urea resin, melamine resin, epoxy resin, unsaturated polyester resin, and silicone resin Materials: 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, Rubber materials such as fluorine rubber and silicone-modified ethylene-propylene rubber are exemplified.

In order to prepare a developer carrier, these materials are used in combination of two kinds or, if necessary, in combination of two or more kinds. The form of the continuous phase and the discontinuous phase (the size of the discontinuous phase, ) Is governed by the difference in compatibility,
The difference in the solubility parameters (SP values) of the polymers used is preferably between 0.2 and 2.5. If the difference in SP value is 0.2 or less, the compatibility is too good, the diameter of the discontinuous phase is small, and it becomes difficult to obtain the characteristics of the discontinuous polymer. Also S
If the difference between the P values is 2.5 or more, the interphase adhesion becomes insufficient,
Cracks, cracks, scratches, etc. occur during use.

The developer carrier used in the present invention includes:
To improve the compatibility between the continuous phase and the discontinuous phase, it is also possible to add a compatibilizer. Compatibilizers include random, graft, and block copolymers, and can be appropriately selected according to the polymer used. Commercial products include Reseda Toa Gosei, Modiper Nihon Yushi,
Etc. are on the market.

As an example of a combination of a continuous phase polymer and a discontinuous phase polymer, polyvinyl acetate, chlorinated polyethylene, polyvinyl chloride, polyvinylidene fluoride, polystyrene-acrylonitrile and the like can be used instead of polymethyl methacrylate. For vinyl, polyethylene oxide, acrylonitrile-butadiene rubber, polymethyl acrylate, polybutylene terephthalate, ethylene-vinyl acetate copolymer, etc., and for polystyrene, polybutadiene, polyisoprene, styrene-butadiene rubber, styrene-acrylonitrile copolymer are used. Polymers, polydimethylphenylene oxide, polymethylphenylsiloxane, etc.
Vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, etc. are natural rubber, butadiene rubber, chloroprene rubber, etc. for styrene-butadiene rubber, and ethylene-propylene-diene rubber for silicone rubber. −
Examples include, but are not limited to, methylene rubber, fluorine rubber, acrylic rubber, butyl rubber, and the like.

In the developer carrier used in the present invention, it is preferable that one of the continuous phase and the discontinuous phase has an insulating property of 10 ¹³ Ω · cm or more. When both are conductive, the chargeability with respect to the toner is reduced, so that it is difficult to obtain a desired toner charge amount and toner adhesion amount.

The developer carrier used in the present invention has a so-called electrode effect in which electrolysis is concentrated on the discontinuous phase islands by making the discontinuous phase polymer conductive at a volume resistivity of 10 ⁶ Ω · cm or less. be able to. In this case, it is preferable that the continuous phase polymer has an insulating property of 10 ¹³ Ω · cm or more from the viewpoint that the electric field is more easily concentrated and the above-described toner charging property. Specific examples of the conductive polymer used in the present invention include those obtained by adding a conductivity-imparting agent to the above-mentioned organic polymers. Examples of the conductivity-imparting agent 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 the like. Conductive oxides; electroless plating products obtained by plating on titanium oxide, mica, etc .; inorganic fillers such as graphite, metal fibers, and carbon fibers; and surfactants. In the case of adding a conductivity-imparting agent, it is preferable that the discontinuous phase polymer has a higher affinity for the conductivity-imparting agent than the continuous phase polymer. This is because when the conductivity imparting agent shifts to the continuous phase during kneading or molding, the conductivity of the discontinuous phase is impaired. In order to minimize the migration of the conductivity-imparting agent, it is preferable to add the conductivity-imparting agent to the discontinuous phase polymer before kneading.

The developer carrying member according to the present invention can be used in either a contact developing method or a non-contact developing method with the latent image carrying member. In the case of the contact developing, the contact with the latent image carrying member is stabilized. For this purpose, the continuous phase is preferably an elastomer, and more preferably both the continuous phase and the discontinuous phase are elastomers. In this case, the rubber hardness is preferably 40 degrees or less (JIS A).

As the polymer of the discontinuous phase, it is preferable to use silicone rubber from the viewpoints of releasability, low hardness, insulating properties, environmental stability and the like. Continuous phase elastomers that can be used for silicone rubber include butadiene rubber,
Diene rubbers such as styrene-butadiene rubber, acrylonitrile-butadiene rubber, isoprene rubber, chloroprene rubber, butyl rubber, ethylene-propylene-diene-
Olefin rubber such as methylene rubber, chlorosulfonated polyethylene rubber, ethylene-vinyl acetate rubber, other fluoro rubber, epichlorohydrin rubber, acrylic rubber,
And the like.

Next, a method for producing the developer carrier of the present invention will be described. Preparation of conductive polymer and insulating polymer When an insulating polymer is used as the conductive polymer, a conductivity imparting agent is kneaded in advance. This can be performed by a usual method used for resin or rubber, for example, a two-roll, three-roll, Banbury mixer, kneader, or the like, and these are selected according to the material to be used. This is not necessary if the polymer itself has low resistance. When necessary, an additive may be added to the insulating polymer. Blend heterogeneous polymers in the same manner as blending polymers. At this time, additives such as a compatibilizer can be added as necessary. Molding The usual methods used for resin and rubber, such as injection molding, extrusion molding, press molding, steam vulcanization molding, spray coating, dipping, etc.
Then, it is molded into a conductive substrate represented by a metal roller, and then polished so that the surface becomes smooth. Incidentally, in order to improve the adhesion to the conductive substrate, a primer can be used, and in this case, the primer is preferably conductive.

[0018]

The present invention will be described in more detail with reference to the following examples.
I do. All parts are by weight. Example 1 EPDM rubber 100 parts of ethylene-propylene-diene-methylene copolymer (Nippon Synthetic Rubber, EP21) 2 parts of t-butylcumyl peroxide (curing agent; Shin-Etsu Chemical Co., C-11) 100 parts of silicone rubber (Shin-Etsu Chemical Industry, KE-550U) 2,5-Dimethyl-2,5-di (t-butylperoxy) hexane 2 parts (curing agent; Shin-Etsu Chemical, C-8) As shown in Table 1, EPDM rubber / Silicone rubber (volume
(Product ratio) = 0/100, 30/70, 70/30, 100
The mixture was kneaded with two rolls at a ratio of / 0. Made of SUS
(14mm diameter) Wound on a cored bar and pressed under the following conditions
Typed. Primary vulcanization: 170 ° C / 10min / 120kg / cm^Two  Secondary vulcanization: 150 ° C./2 hours After that, polishing is performed, and a 20 mm diameter developing carrier (roller)
Was made respectively. Developer support (sheet) in the same way
Also created. 500x microscopic observation of sheet cross section
Of the continuous phase (EP
DM) and a discontinuous phase (silicone rubber) having an average diameter of about 8 μm.
Was observed.

The developer carrying member was mounted on the developing unit shown in FIG. The members used are shown below. Toner thinning blade: urethane rubber (2 mm thick) Toner supply roller: conductive urethane sponge Toner: positively charged toner The following items were evaluated for each developing device. [Toner Releasability] The toner on the developer carrier was removed with air, and the following rank evaluation was performed on the toner melt adhesion state on the surface. Rank 1 No adhesion 2 Slight adhesion 3 Large amount of adhesion than Rank 2, but easily removed by wiping 4 Toner is not removed by wiping in a molten state. [Abrasion resistance] Laser micro gauge (Iwatsu, DT40
02A), the diameter of the developer carrying member was measured, and the amount of decrease in the diameter was measured. The evaluation was carried out after idling the developer carrier for 100 hours.
Similar evaluations were made of temperature / humidity: (30 ° C./90%), (23
C./60%) and (10.degree. C./15%). Table 1 shows the results.

[Table 1]

[0020]

As can be seen from the above description, when the continuous phase and the discontinuous phase are composed of the EPDM rubber and the silicone rubber, the releasability, abrasion and environmental resistance of the developer carrier are sufficiently satisfied.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a typical developing device according to the present invention.

FIG. 2 is an explanatory diagram of a developer carrier mounted on the developing device of the present invention.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 15/08

Claims (4)

(57) [Claims] The developer carrier is discontinuous with a continuous phase polymer.
Phase polymer, discontinuous due to toner supply member
Triboelectric phase on the surface of the developer carrier
The developer is loaded by selectively retaining the charge
Many small closed electric fields are formed near the body surface, and this developer
A non-magnetic one-component toner is supplied onto a carrier,
The developer is carried on the surface of the developer carrying member by the
Used for image forming method to visualize electrostatic latent image with developer
A developer carrier , wherein at least the surface of the developer carrier is blended with two or more different amorphous polymers and then molded to form a continuous phase (sea part) and a discontinuous phase (island part). ) a developing device of an electrostatic latent image, characterized in that it is constituted by is formed. 2. A developing apparatus according to claim 1, the average diameter of the irregular polymer phase not continuous phase being in the range of 1Myuemu～500myuemu. 3. The developing apparatus according to claim 1, wherein the volume resistance of the continuous phase is 10 ¹³ Ω · cm or more, and the volume resistance of the discontinuous phase is 10 ⁶ Ω · cm or less. 4. The developing device according to claim 1, wherein the difference between the solubility parameter (SP value) of the continuous phase polymer and the discontinuous phase polymer is in the range of 0.5 to 2.5.