JPH0422979A - Developer carrying member - Google Patents

Abstract

PURPOSE:To obtain the developer carrying member which does not generate filming by incorporating a fluorine surfactant into at least the surface of the carrying member or near the surface thereof. CONSTITUTION:This developer carrying member is so constituted that dielectric parts and conductor parts coexist in microareas on the surface. Toners 60 carried by a carrying member 40 are electrified by friction and are electrostatically stuck to the dielectric parts. The electric fields of this time are microfields (closed electric fields) and form the electric fields of a large electric field inclination to stick the toners 60 in multiple layers. The carrying member is constituted to contain the fluorine surfactant on the surface or near the surface in this case to decrease the coefft. of dynamic friction of the surface. The developer carrying member 20 which does not generate toner filming is obtd. in this way.

Description

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

[Conventional technology]

An electronic copying machine that forms an electrostatic latent image on a latent image carrier and visualizes this using a developer to obtain a recorded image.

2. Description of the Related Art In image forming apparatuses such as printers and facsimiles, dry-type developing devices that use powdered developer are widely used.

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

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

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

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

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

However, when a non-magnetic one-component developer is used, it is difficult to satisfy the above requirements because it cannot be supported on a developer carrier by magnetic force. Various countermeasures have been proposed in the past.1 For example, in Japanese Patent Application Laid-Open No. 61-42672, a dielectric (insulator) layer is laminated on the surface of a developer carrier (developing roller). A developer supply member made of, for example, a sponge roller is brought into pressure contact with the dielectric material, and the two are frictionally charged to opposite polarities, and non-magnetic toner charged to the opposite polarity to the dielectric material is electrostatically attached to the dielectric material. A method of transporting such a -component developer to a development area has been proposed. However, even with this method, it is not possible to sufficiently increase the strength of the electric field formed near the dielectric surface, so it is difficult to carry a large amount of toner on the surface of the developing roller. Due to the insufficient amount of agent, it is difficult to form a high-density visible image.

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

In addition, as a toner supply member, 102 to 106 Ω・a
m conductive foam (Japanese Unexamined Patent Publication No. 60-229057)
, elastic body with skin layer (Japanese Unexamined Patent Publication No. 60-229060) and fur brush (Japanese Unexamined Patent Publication No. 61-42672)
It has been proposed to use a roller, etc., and as a developing roller.

Metal body with uneven surface (Japanese Unexamined Patent Publication No. 60-53976), integral insulated roller (Unexamined Japanese Patent Application No. 55-46768)
Publication) Medium and low antibody coated roller (Japanese Patent Application Laid-Open No. 58-13278
JP-A-53-36245) and an electrode roller having an insulator and a conductive surface (JP-A-53-36245).

Furthermore, in a developing device using a non-magnetic component developer,
In Japanese Patent Application Laid-Open No. 60-229057, a sponge roller,
JP-A No. 62-229060 uses an elastic roller, and JP-A No. 61-52663 uses a fur brush or the like to apply an electric charge to the toner through frictional charging between the toner and a replenishing member, and furthermore, by contact with a developing roller. The toner is electrostatically adhered to the developing roller by friction, and a layer thickness regulating member such as a blade is further used.

The toner layer is controlled to develop the latent image on the photoreceptor. Various materials are used for the developing roller, such as insulating materials, medium resistance materials, and laminated materials.

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

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

Regarding the amount of adhesion, the amount of adhesion on the developing roller is 0.
1-0.3mg/ci+", but 0.3mg/ci+" on the transfer paper.
4-0.5mg/c+o" is required, and the amount of toner adhesion is covered by increasing the speed of the developing roller to 3 to 4 times the speed of the photoreceptor.
The problem with rotating the developing roller twice as much is that a phenomenon of "toner from the trailing edge" occurs, that is, when a solid area is developed, the density at the trailing edge of the image becomes higher. To prevent this phenomenon, the speed of the developing roller should be made close to the speed of the photoreceptor. In other words, it is necessary to increase the amount of toner adhered to the developing roller and reduce the number of revolutions per rotation.

On the other hand, with color toner, the degree of coloring is smaller than that of black toner, and when trying to improve the "from the rear end of the toner", the color characteristic is 0.8 to 1.2 m, which is even more than that of black toner.
An amount of adhesion on the developing roller of g/cm2 is required.

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

As a method to solve these problems, the present inventors
First, a one-component developer consisting of a non-magnetic toner to which an auxiliary agent is externally added as necessary is supplied to a rotating and parked developer carrier, and the developer is carried on the surface of the carrier. In a developing area where the latent image carrier and the developer carrier face each other, the electrostatic latent image formed on the latent image carrier is transferred by the developer carried by the developer carrier. In the visualization development method, a large number of minute closed nitrogen fields are formed near the surface of the developer carrier by selectively holding charges on the surface of the developer carrier, and the charged toner is attracted by this closed electric field. and deposit and carry the developer on the surface of the developer carrier,
We proposed an image forming method in which an electrostatic latent image is visualized using the developer carried thereon.

In this invention, since a large number of micro-closing fields (micro-fields) are formed near the surface of the developer carrier, the electric field strength can be significantly increased compared to the conventional method, and a large amount of sufficiently charged non-nitride fields can be generated. This device has many advantages such as being able to carry magnetic toner on a developer carrier and transport it to a developing area.

[Problem to be solved by the invention]

However, even in the image forming method in which a large number of microfields are formed near the surface of the developer carrier as described above, there are many members on the developer carrier, such as a toner supply member, a toner layer thickness regulating member, (during contact development) a photoreceptor, etc. is in contact with the photoreceptor. Therefore, if the friction coefficient of the surface of the developer carrier is large, the rotational torque of the developer carrier becomes large, causing vibrations and requiring a powerful motor. On top of that.

There are problems such as insufficient agitation of the toner on the developer carrier, resulting in so-called filming phenomenon in which the toner sticks to the surface of the developer carrier, or an insufficient amount of charge on the toner.

Therefore, it is an object of the present invention to provide a developer carrier that solves the problems of filming and insufficient toner charge in the image forming method described above.

[Means to solve the problem]

As a result of intensive study, the inventors found that! It has been found that a developer carrier containing a fluorine-based surfactant at least on the surface or near the surface of the image-side carrier is compatible with the above purpose,
The present invention has now been completed.

That is, according to the present invention, 1
By selectively retaining charge.

Forming a large number of minute closed nitrogen fields near the surface of a developer carrier, and supplying a non-magnetic one-component developer made of toner to which an auxiliary agent is externally added as necessary onto the developer carrier; A developer carrier used in an image forming method in which the developer is supported on the surface of the developer carrier by the micro-nitriding field and an electrostatic latent image is visualized by the carried developer, the developer carrier comprising at least the surface of the developer carrier. Alternatively, there is provided a developer carrier characterized in that a fluorine-based surfactant is contained near the surface.

In the image forming method using the developer carrier of the present invention, a large number of micro-closing fields are formed near the surface of the developer carrier, so the electric field strength can be significantly increased compared to the conventional method, and By containing a fluorine-based surfactant on or near the surface of the developer carrier, the coefficient of friction on the surface of the developer carrier is reduced, and as a result, toner filming does not occur and a large amount of sufficiently charged particles The magnetic toner can be carried on the developer carrier and transported to the development area.

Below, five such image forming methods will be explained.

FIG. 1 shows an outline of a typical developing device useful for carrying out this image forming method, centering on the developer carrier section. In FIG. 1, toner 6 contained in a toner tank 70 is shown.
0 is a toner supply member (sponge roller, fur brush, etc.) 4 by a stirring blade (toner supply auxiliary member) 50.
0, the toner 60 is forcibly brought to the toner supply member 4
0. On the other hand, the developer carrier (developing roller) 20 of the present invention, which has completed the development, rotates in the direction of the arrow (for example, at 400 rpm) and reaches the contact portion with the toner supply member 40 . The toner supply member 40 rotates in the opposite direction to the developer carrier 20 (for example, 300 rpm+m) L, charges the developer carrier 20 and the toner 60, and causes the toner 60 to adhere onto the developer carrier 20.

Further, the developer carrier 20 rotates, and the toner adhering to the developer carrier 20 is removed by the toner layer thickness regulating member (elastic blade) 3.
0, the charging is stabilized while the thickness is controlled, and the developing area 80 is reached. In the development area 80, the latent image is developed by contact or non-contact development.

Here, if necessary, bias such as direct current, alternating current, direct current superimposed alternating current, pulse, etc. can 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 this type (electrode type) developer carrier 20 will be explained.

As an example of the developer carrier 20, as shown in FIG. 2, the developer carrier 20 is configured such that a dielectric portion and a conductive portion coexist in a small area on its surface.

The size of the area is assuming that the shape is circular.

The area ratio in which minute areas with diameters of 10 to 500 mm are distributed randomly or according to a certain rule is preferably in the range of 20 to 60% of the area of the conductive part.

Toner adhesion is as follows. First, the developer carrier 20 that has completed development rotates in the direction of the arrow and comes into contact with the toner supply member 40 . The remaining toner in the non-image area 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 on the developer carrier 20 and toner due to the previous development are as follows:
It is stabilized and initialized by friction. Next, the toner carried by the supply member 40 is charged by friction and electrostatically adheres to the dielectric portion of the developer carrier 20 . At this time, the polarity of the toner is opposite to the charge on the photoreceptor, and the dielectric portion of the developer carrier 20 is of the same polarity.

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 with a large electric field gradient, making it possible to adhere the toner in multiple layers. Further, since the adhered toner is in a closed electric field, it is strongly attracted to the developer carrier 20 side and becomes difficult to separate.

The thickness of this toner layer is further controlled by a toner layer thickness regulating member 30, and the toner layer reaches the development area 80.

The electric field between the developer carrier 20 and the electrostatic latent image carrier (photoreceptor) 10 in the development area 80 has a large electrode effect, and the toner on the developer carrier 20 is transferred to the electrostatic latent image carrier 10. The electric field becomes easy to adhere to, and development is performed.

Next, the developer carrier of the present invention will be explained.

As the conductive material, one having a resistance of 10 12 Ω·cm or less, preferably 1O 8 Ω·cm or less can be used. Specific examples include metals such as AQ, SO5, Fe, Ni, -
T! 5. In addition to mixes, examples include organic polymers to which a conductivity imparting agent is added. In this case, the organic polymers include the following.

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

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

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

On the other hand, the material used for the dielectric part can be used as long as it is insulating, but it should be 1013Ω・011 or more, especially 10'1
It is preferable to have a resistance of Ω·cm or more. As a specific example,
Examples include the organic polymers listed in the conductive materials.

The developer carrier of the present invention is characterized in that it contains a fluorine-containing surfactant at least on its surface or near its surface. As the fluorine-based surfactant in this case, any fluorine compound containing a fluoroalkyl group can be used.

Generally nonionic, anionic, and cationic.

Although there are amphoteric ones, anionic ones are preferable.

Specific examples of these fluorine-based surfactants include nonionic ones, such as perfluoroalkyl group-containing lipophilic group-containing oligomers, perfluoroalkyl group-containing hydrophilic group-containing oligomers, perfluoroalkyl ethylene oxide adducts, etc. . In addition, examples of cationic substances include perfluoroalkyl-containing quaternary ammonium salts.

Examples of anionic compounds include sulfonic acids containing perfluoroalkyl, monovalent metal salts of carboxylic acids, and phosphate esters, and examples of amphoteric compounds include betaine containing perfluoroalkyl.

Commercially available products of such fluorine-based surfactants include Surflon (manufactured by Asahi Glass Co., Ltd.), Megafac (manufactured by Dainippon Ink Chemical Co., Ltd.), FTOP (manufactured by Asahi Glass Co., Ltd.), Futtergelet (manufactured by Neos Co., Ltd.), Examples include Unidyne (manufactured by Daikin Industries).

These can be appropriately selected from the viewpoint of compatibility with the materials used. It is also possible to mix and use various surfactants. The amount of the fluorosurfactant mixed is preferably 0.1 to 50 parts by weight based on 100 parts by weight of the solid content of the material used. More preferably, it is 0.5 to 20 parts by weight. If it is less than 0.1 part by weight, the effect of reducing the coefficient of friction will not be sufficiently exhibited, and if it exceeds 50 parts by weight, the mechanical strength of the material will decrease. 6. How to make the developer carrier of the present invention ,for example.

(i) First, a conductive material containing a fluorine-based surfactant is layer-molded on the surface of a metal roller using a conventional molding method such as injection molding, extrusion molding, press molding, spray coating, or dipping.

(ii) The surface is grooved by fleur-de-lis knurling, etc. In this case, the grooves are 0.1-0.5 eun pitch.

Processed at an angle of approximately 45° to the longitudinal direction of the roller)
[See Figure 3(a)], (iii) Next, a dielectric material containing a fluorine-based additive in advance is applied to the grooved metal surface.
It is coated by spraying, dipping, etc., and molded at a predetermined curing or drying temperature/time, and the coating thickness is adjusted so that the grooves are completely filled.) [Refer to Part 3]
Figure (b)), (iv) Next, the surface of the roller is cut or polished so that the conductive surface and dielectric surface are mixed in a small area, and the area of the conductive part is reduced to 20 to 60% [see The method shown in FIG. 3(C) is adopted.

A typical configuration example of the surface of the developer carrier of the present invention is as follows:
Shown in Figures (a)-(d). Figure 4 (a) and (b)
In the configuration shown in , when a material 1 to which a fluorine-based surfactant can be added to the conductive and dielectric materials is used, such as organic polymers, the fluorine-based surfactant is directly added to both to improve friction. The coefficient can be reduced. As shown in FIG. 4(c), in an example in which an electric field gradient is formed by a difference in capacitance between dielectric parts, it is sufficient to add a fluorine-based surfactant only to the dielectric. In addition, as shown in Figure 4(d), when using materials such as metal materials to which it is impossible to add a surfactant, a layer containing a fluorine-based surfactant may be installed as a surface layer. good.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that 1 part represents part by weight.

Examples Conductive material Sn-based catalyst (trade name Cat, 55: manufactured by Sanyo Kasei Chemical Industry Co., Ltd. 300 parts of ethyl ketone nonionic fluorine-based surfactant 1 part (trade name Surflon S-382; manufactured by Asahi Glass Co., Ltd.) Dielectric material: Carbon black fibers are removed from the above conductive material formulation.

Using the materials of the above formulation, the developer carrier (
A developing roller) was manufactured.

(i) A SUS roller was coated with the above conductive material by spray coating, cured at 100° C. for 71 hours, and then polished to obtain a conductive layer with a thickness of 50 mm.

(ii) With fleur-de-lis knurling on the roller surface, ■
A groove was provided. (2) The grooves had a pitch of 0.2Ill and were machined at approximately 45 degrees to the longitudinal direction of the roller.

(ni) Apply the above dielectric material to the V-grooved roller surface,
It was molded in the same manner as (i). The coating thickness was such that the grooves were completely filled.

(iv) The surface of the roller was polished so that a conductive surface and a dielectric surface coexisted in a small area, so that the conductive part area was 50%.

Dynamic friction coefficient and toner filming tests were conducted using the following method.

Measurement of Dynamic Friction Coefficient A conductive material and a dielectric material were spray coated onto a PET sheet to obtain a sheet with a film thickness of 20A@.

Friction coefficient measuring device: HEIDON 14 type surface property measuring device Plane indenter: 30mm+ x 30mm Indenter load: 1
kg Indenter feed speed: 50mm/+win Dynamic friction coefficient μ=W (strain gauge value)/P (pressing force)
The coefficient of dynamic friction was calculated.

Attach the toner filming developing roller to the developing device shown in FIG.
After conducting a 0-hour developing roller drive test.

The toner on the roller surface was blown off with air, the roller surface was transferred to a tape, and the filming state of the toner was visually observed.

In the above developing device, the toner thinning blade is made of urethane rubber, the toner supply roller is made of conductive urethane sponge, and the toner is negatively charged toner.
Loaded.

Comparative Example A developing roller and sheet were prepared in the same manner as in the example except that the fluorine-based surfactant in the conductive material and dielectric material was not used, and the measurement of the coefficient of dynamic friction and toner filming were carried out in the same manner as in the example. I conducted a test.

evaluation Table 1 shows the measurement results of the dynamic friction coefficient.

From the results shown in Table 1, it can be seen that the surface dynamic friction coefficient of the developing roller of the present invention is reduced compared to that of the comparative example.

Also, as a result of the filming test, in the example, the toner fusion on the developing roller surface was I! However, in the comparative example, it was observed that the toner was almost uniformly fused to the roller surface.

〔Effect of the invention〕

Since the developer carrier of the present invention contains a fluorine-based surfactant on or near the surface, the coefficient of dynamic friction on the surface of the developer carrier is reduced.

Therefore, by selectively retaining a charge on the surface of the developer carrier, a large number of minute closed electric fields are formed near the surface of the developer carrier, and as needed, A non-magnetic one-component developer made of toner externally added with an auxiliary agent is supplied, and the developer is supported on the surface of the developer carrier by the fine, J-closed electric field, and the electrostatic latent is caused by the supported developer. When the developer carrier of the present invention is used in an image forming method for visualizing an image, a large amount of sufficiently charged non-magnetic one-component developer is carried on the developer carrier and transported to the development area. As a result, toner filming does not occur, and high-quality images with high density can be obtained.

[Brief explanation of drawings]

The first @ is a schematic cross-sectional view centered on a developer carrier portion showing an example of a developing device in which a microfield electric field is formed on a developer carrier useful for implementing the present invention. Also,
FIG. 2 is a schematic cross-sectional view for explaining a state in which a closed electric field is generated by a microfield on a developer carrier in the apparatus shown in FIG. Further, FIGS. 3(a) to 3(c) are schematic cross-sectional views showing the surface state during the manufacturing process of the developer carrier of the present invention. Moreover, FIGS. 4(a) to 4(d) are schematic cross-sectional views showing examples of the structure of the surface of 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. Patent applicant Rico Co., Ltd.

Claims (1)

[Claims] (1) By selectively retaining electric charges on the surface of the developer carrier, a large number of minute closed electric fields are formed near the surface of the developer carrier, and as needed, A non-magnetic one-component developer made of toner externally added with an adjuvant is supplied, the developer is supported on the surface of the developer carrier by the minute closed electric field, and the electrostatic latent image is made visible by the supported developer. 1. A developer carrier used in an image forming method, characterized in that the developer carrier contains a fluorine-based surfactant at least on the surface or near the surface.