JP2002014535A - Developing roller and developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing roller which is capable of obtaining good images and maintaining the good images over a long period of time and a developing device using such developing roller. SOLUTION: This developing roller is constituted by forming a semiconductive resin layer on the outer periphery of a metallic roller and carries a thin layer consisting of a nonmagnetic one-component developer on the front surface of this semiconductive resin layer and comes into contact in this state with a belt-like latent image holding member to supply the developer to the latent image holding member. The semiconductive resin layer of the developing roller contains a phenolic resin. This developing device is mounted with the developing roller described above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing roller for visualizing an electrostatic latent image with a non-magnetic one-component developer in an electrophotographic apparatus such as a copying machine or a printer or an electrostatic recording apparatus. More specifically, with respect to the mounted developing device, a developing roller which is free from image defects such as fogging, image unevenness and ghost, and which can obtain a good image even in long-term use, and which has excellent durability, is used. Developing device.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic apparatus such as a copying machine or a printer, or an electrostatic recording apparatus, a latent image holding member such as a photoconductor holding an electrostatic latent image is developed with a non-magnetic one-component developer and visualized. As a method for performing the development, a contact developing method in which development is performed while a latent image holding member and a developer carrying member such as a developing roller are in contact with each other is performed. In this developing method, it is necessary that the latent image holding member and the developer carrying member come into contact with a wide nip. In order to widen the nip, at least one of the latent image holding member and the developer carrying member needs to have flexibility. Generally, the latent image holding member is a rigid drum and the developer carrying member is elastic. Often a roller. On the other hand, there is a developing method in which the latent image holding member is formed in a belt shape so as to have flexibility, and the developer carrying member is a metal roller. The latter method can increase the nip width, is suitable for high-speed operation, has little damage to the developer, and has excellent durability.

[0003]

However, the metal roller alone has insufficient charging ability to the developer, causing image fog, image unevenness, ghost, etc., resulting in image defects. Further, in long-term use, the developer adheres to the roller, resulting in an image defect. In order to solve these problems, a resin layer is formed on the outer periphery of the metal roller to improve the chargeability with respect to the developer and the long-term durability, but it has not been sufficient yet. The present invention has been made in view of the above circumstances, and provides a developing roller capable of obtaining a good image and maintaining a good image for a long time, and a developing device using the developing roller. It is an object.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, by forming a resin layer containing a phenolic resin on the outer periphery of a metal roller, the charging of the developer is prevented. A developing roller that is excellent in performance, provides a good image without image fogging, image unevenness, ghost, etc., and can provide a good image without a developer adhering to the roller even during long-term use. Was found. The present invention has been completed based on such findings. That is, the first invention of the present invention comprises a semiconductive resin layer formed on the outer periphery of a metal roller, and a thin layer made of a non-magnetic one-component developer is carried on the surface of the semiconductive resin layer. In this state, a developing roller that contacts the belt-like latent image holding member and supplies the developer to the surface of the latent image holding member, wherein the semiconductive resin layer contains a phenol resin. A developing roller. A second invention is the developing roller according to the first invention, wherein the phenol resin is of a resol type. In the third invention, the semiconductive resin layer contains a friction reducing agent selected from a silicone resin, a fluorine resin, a fluorine-based surfactant, a silicone-based surfactant, a silicone-based coupling agent and silica powder. A developing roller according to the first invention or the second invention. A fourth invention is the developing roller according to any one of the first to third inventions, wherein the metal roller is formed of a metal selected from aluminum, stainless steel, and an iron alloy. According to a fifth aspect of the present invention, there is provided a belt-shaped latent image holding member, and a semiconductive resin layer formed on an outer periphery of a metal roller. And a developing roller that, in that state, comes into contact with the belt-shaped latent image holding member and supplies the developer to the surface of the latent image holding member. A developing device using the developing roller according to any one of the first to fourth aspects of the present invention.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The developing roller of the present invention has a semiconductive resin layer formed on the outer periphery of a metal roller. The material of the metal forming the roller is not particularly limited as long as it has a low electric resistance. For example, aluminum, stainless steel, iron alloy and the like are used. The shape of the roller may be any shape as long as its cross-sectional outer periphery is circular, and may be a hollow body or a solid body. Usually, an aluminum sleeve is preferably used for weight reduction. FIG. 1 shows an example of a schematic cross-sectional view of the developing roller of the present invention. A metal roller 3 is formed by fitting a metal cap 3 with a shaft at both ends of the metal sleeve 2.
Further, a semiconductive resin layer 1 is formed on the outer peripheral surface of the metal sleeve 2. A voltage is applied to the developing roller through the metal shaft.

[0006] The semiconductive resin layer formed on the outer periphery of the metal roller contains a phenol resin. As the phenol resin, either a resol type or a novolak type can be used. More specifically, various modified phenols such as simple phenolic resin obtained by reacting phenol and formalin, resorcinol resin using resorcinol instead of phenol, resin using phenol and resorcinol in combination, melamine-modified, xylene-modified and epoxy-modified Resin can be used. Among them, a simple phenol resin, a resorcin resin, and a mixture thereof are preferably used. A resol type phenol resin is particularly preferable because a cured film can be formed only by heating without using a crosslinking agent.

Further, when the developing roller of the present invention is used in a printer or the like that requires high speed, it is possible to prevent the occurrence of low-pressure fog due to overcharging of the developer in addition to contamination and high charging of the developer. Is required, it is preferable to mix a conductive material in the resin, and it is particularly preferable to mix a conductive powder such as carbon black.
By blending a conductive material, the occurrence of low-pressure fog can be effectively prevented. As a conductive material,
There are conductive powders and ionic conductive substances. Examples of the conductive powder include conductive carbon such as Ketjen Black EC and acetylene black, SAF, ISAF, HAF, and FE.
Rubber carbon such as F, GPF, SRF, FT, MT, etc.
Metals and metal oxides such as color (ink) carbon, pyrolytic carbon, natural graphite, artificial graphite, antimony-doped tin oxide, titanium oxide, zinc oxide, nickel, copper, silver, germanium, etc. ,
Examples thereof include conductive polymers such as polyaniline, polypyrrole, and polyacetylene. Among them, carbon black is inexpensive and easily controls conductivity in a small amount. As the ion conductive substance, sodium perchlorate,
Inorganic ionic conductive substances such as lithium perchlorate, calcium perchlorate, and lithium chloride, as well as modified aliphatic dimethylammonium ethosulfate, stearylammonium acetate, laurylammonium acetate, octadecyltrimethylammonium perchlorate, and tetrabutylammonium fluoride Organic ionic conductive substances such as acid salts.

[0008] The conductive powder is based on 100 parts by weight of the resin.
In the range of 0.1 to 50 parts by weight, especially 1 to 30 parts by weight.
Appropriately used. 100 parts by weight of ionic conductive material resin
To 0.005 to 5 parts by weight, especially 0.5 to 3 parts by weight
It is suitably used in the range. The volume resistivity of the resin layer is 10⁸
-10^FifteenΩ · cm is preferable, and especially 10^Ten-10 ¹⁴Ω
cm is preferred. If the volume resistivity is too low,
The charge amount of the agent becomes too low, and image fogging occurs. body
If the product resistivity is too high, the latent image carrier and the developer carrier
Voltage bias is insufficient during
You.

The means for applying the resin component to the surface of the metal roller is not particularly limited, but a method of surface-treating the metal roller with a resin solution containing the resin component is preferably employed. In this case, the solvent for preparing the resin solution may be any solvent as long as it dissolves the resin, but is usually methanol, ethanol, lower alcohols such as isopropanol, acetone,
Ketones such as methyl ethyl ketone and cyclohexanone,
Toluene, xylene and the like are preferably used.

[0010] The surface treatment can be performed by a spray method, a roll coater method, a dipping method or the like after preparing a treatment liquid. For example, for the surface treatment by dipping, a method of immersing the resin solution in a resin solution at room temperature, pulling it up, and drying it can be adopted. When the spray method is employed, the resin concentration in the processing solution can be set higher than in the dipping method.

By the surface treatment with the above resin component,
Although the friction of the roller surface can be reduced to some extent, various additives can be used in the resin component to further reduce the friction. In this case, as an additive capable of reducing friction without causing contamination of the photoreceptor and without reducing the uniformity of the surface treatment by the resin component, silicone resin, silicone resin powder, fluororesin, fluorine-based and Silicone-based surfactants, silicone-based coupling agents, and silica powder are preferably used. Examples of the silicone resin include those soluble in a solvent, for example, methyl silicone, methyl phenyl silicone, a modified product thereof, and a silicone epoxy block copolymer. Examples of the silicone resin powder include fine powders of methyl silicone or methyl phenyl silicone polymer, amino group-modified silicone polymer, etc., and spherical and amorphous particles having an average particle size of 0.1 to 100 μm are preferably used. Used.

Examples of the fluorine resin include polytetrafluoroethylene, polyvinylidene fluoride, polyfluoroethylene propylene, and PFA resin. Examples of the fluorine-based surfactant include, for example, an ionic compound in which an alkyl fluoride and a carboxylic acid, a carboxylate, and a sulfonate are bonded, a nonionic compound in which an alkyl fluoride and an alcohol, an ether, and the like are bonded, Polymers such as polymers and copolymers containing an alkyl fluoride in the side chain and main chain are exemplified. Examples of the silicone-based surfactant include high-molecular-weight surfactants such as a general conjugate of methyl silicone such as siloxane oxyethylene and a hydrophilic or lipophilic segment, and a copolymer of methyl silicone and an acrylic segment. Can be Examples of the silicone-based coupling agent include not only a normal silane coupling agent but also a silane having an amino group, an isocyanate group, a vinyl group, or the like introduced into a terminal. These may be used alone or in combination of two or more. The amount of the friction reducing agent is 1 to 100 parts by weight, preferably 10 to 75 parts by weight, based on 100 parts by weight of the resin component.

The thickness of the resin layer is preferably 1 to 100 μm, particularly preferably 5 to 50 μm. If the resin layer is too thin, the life of the developing roller is shortened due to wear due to friction with the developer and the layer regulating blade. If the resin layer is too thick, the production cost increases. The surface roughness of the developing roller of the present invention is not particularly limited, but is preferably 0.1 to 5 μm in JIS 10-point average roughness Rz, particularly
It is preferably 0.3 to 3 μm. If Rz is too large, the charge amount of the developer decreases, and image fogging occurs. R
If z is too small, the transport amount of the developer decreases, and the image density decreases.

The developing roller of the present invention is suitably used for a non-magnetic one-component developing device having a belt-like latent image holding member. FIG. 2 is a schematic view of an example of a developing device equipped with the developing roller of the present invention. 2, first, a photoconductor (latent image carrier) 5 is uniformly charged to a predetermined potential by a charger 6. Next, by writing information with the laser beam L, an electrostatic latent image is formed on the surface of the photoconductor 5. On the other hand, the developer is supplied to the outer peripheral surface of the developing roller 4 by the developer supply roller 7 in the developer box 8. further,
The developer is regulated by the developer layer regulating blade 10 to form a thin layer of the developer layer on the outer peripheral surface of the developing roller 4. The developer is frictionally charged between the developer supply roller 7 and the developing roller 4 and between the developer layer regulating blade 10 and the developing roller 4 and takes a predetermined charge. Developing roller 4
Is rotated while abutting on the photoconductor 5, and a developing bias is applied between the two by a power source (not shown). The charged developer on the developing roller 4 moves onto the photoreceptor 5 by this developing bias, and a visible image of the developer is formed to perform development. The visible image of the developer on the photoconductor 5 is transferred onto a recording medium P such as paper by a transfer bias between the transfer roller 9 and the photoconductor 5 to form a transfer image. Further, the transferred image is heat-fixed by a fixing device (not shown) to form a permanent image. The surface of the photoconductor 5 is cleaned by a cleaning device (not shown) and is reused.

[0015]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples. Example 1 A metal roller having an end cap with a metal shaft at both ends of an aluminum sleeve was prepared. A resol type phenol resin was dissolved in ethanol so that the resin concentration became 20% by weight. Further, 10 parts by weight (PHR) of furnace carbon black (CB) was added to 100 parts by weight of the resin solid content, and the mixture was uniformly dispersed using a paint shaker to prepare a coating liquid. The metal roller was immersed in this coating solution, pulled up,
The resin was cured by heating at 10 ° C. for 4 hours to obtain a developing roller. Table 1 shows various characteristics of the obtained developing roller.

[0016]

[Table 1]

Comparative Examples 1 and 2 Developing rollers were manufactured in the same manner as in the examples, using soluble nylon and polymethyl methacrylate as the resin components and adjusting the amount of CB added and the resin concentration. However, as a solvent for preparing the coating liquid, a methanol solvent and a mixed solvent of toluene / methyl ethyl ketone were used. Table 2 shows properties of the produced developing roller.

[0018]

[Table 2]

The developing rollers manufactured in the above Examples and Comparative Examples were incorporated in the developing device shown in FIG.
An image forming test was conducted using the non-magnetic one-component developer of No. 1. Table 3 shows the results.

[0020]

[Table 3]

The durable image is an image after 5000 halftone images have been formed. In the examples, it is recognized that good images can be obtained not only for the initial images but also for the durable images. In contrast, in the comparative example,
The initial image was somewhat difficult, and the durable image was significantly poor. When observing the developing roller of the comparative example, the developer was fused in spots around the outer periphery of the developing roller. However, no fusion of the developer was observed with the developing roller of the example.

[0022]

The developing roller of the present invention does not cause image defects such as fog, image unevenness and ghost when used in a developing device, and can provide a good image even in long-term use. It has excellent durability.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a cross section of a developing roller of the present invention.

FIG. 2 is a schematic diagram illustrating an example of a developing device equipped with a developing roller of the present invention.

[Explanation of symbols]

 1: Semiconductive resin layer 2: Metal sleeve 3: Metal end cap with shaft 4: Developing roller 5: Photoconductor (latent image holder) 6: Charger 7: Developer supply roller 8: Developer box 9: Transfer roller 10: Developer layer regulating blade

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F16C 13/00 F16C 13/00 A EF term (reference) 2H077 AD06 EA14 EA15 FA13 FA25 FA26 3J103 AA02 AA13 AA24 AA32 AA41 AA51 CA04 CA05 CA13 FA12 FA18 GA02 GA52 GA57 GA58 HA01 HA03 HA04 HA05 HA06 HA15 HA20 HA22 HA31 HA32 HA33 HA37 HA43 HA47 HA54 4J002 BD122 BD132 BD142 BD152 CC031 CC041 CC181 CD061 CP032 CP092 CP172 CP182 DJ016 EX017 EX077 FA082 FD147 GM0000 176

Claims (5)

[Claims] A semiconductive resin layer is formed on the outer periphery of a metal roller, and a thin layer made of a non-magnetic one-component developer is carried on the surface of the semiconductive resin layer. A developing roller for supplying the developer to the surface of the latent image holding member in contact with the latent image holding member, wherein the semiconductive resin layer contains a phenol resin. 2. The developing roller according to claim 1, wherein the phenol resin is of a resol type. 3. The semiconductive resin layer further contains a friction reducing agent selected from silicone resins, fluorine resins, fluorine surfactants, silicone surfactants, silicone coupling agents and silica powder. The developing roller according to claim 1, wherein: 4. The developing roller according to claim 1, wherein the metal roller is formed of a metal selected from aluminum, stainless steel, and an iron alloy. 5. A belt-like latent image holding member, and a semiconductive resin layer formed on the outer periphery of a metal roller, and a thin layer made of a non-magnetic one-component developer on the surface of the semiconductive resin layer. And a developing roller that contacts the belt-shaped latent image holding member and supplies the developer to the surface of the latent image holding member in this state, wherein the developing roller is used as the developing roller. ~ 4
A developing device using the developing roller according to any one of the above.