JP3221295B2 - Method and apparatus for developing electrostatic latent image - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for developing an electrostatic latent image in an electrophotographic apparatus such as a copying machine or a printer or an electrostatic recording apparatus.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic process, as a developing method for developing an electrostatic latent image using a non-magnetic one-component developer as a developer (hereinafter, referred to as "toner"), a latent image is held. A developing method (pressure development method) of supplying toner to a photosensitive drum or the like and attaching the toner to the latent image on the photosensitive drum to visualize the latent image is known.
Since no magnetic material is required, the apparatus can be simplified and downsized easily, and the toner can be easily colored.

In this pressure developing method, a developing roller carrying toner is brought into contact with a latent image holding member such as a photosensitive drum holding an electrostatic latent image, and the toner adheres to the latent image on the latent image holding member. Therefore, it is necessary to form the developing roller with an elastic body having conductivity.

That is, in this pressure developing method, as shown in FIG. 1, for example, a developing process is performed between a toner applying roller 4 for supplying toner and a photosensitive drum 5 holding an electrostatic latent image. The roller 1 is placed in contact with the photosensitive drum 5, and the developing roller 1, the photosensitive drum 5 and the toner applying roller 4 are rotated, so that toner is supplied to the surface of the developing roller 1 by the toner applying roller 4. The toner is arranged in a uniform thin layer by the developing blade 6, and the toner formed on the thin layer adheres to the latent image on the photosensitive drum 5 from the developing roller 1 to visualize the latent image. I have. In the drawing, reference numeral 7 denotes a transfer roller, which transfers an image to a recording medium such as paper.
In the drawing, reference numeral 8 denotes a cleaning unit, which removes toner remaining on the surface of the photosensitive drum 5 after transfer by a cleaning blade 9 thereof.

In this case, the developing roller 1 includes a photosensitive drum 5
As shown in FIG. 4, a conventional developing roller 1 has a silicone rubber on the outer periphery of a shaft 2 made of a good conductive material such as a metal, as shown in FIG. Acrylonitrile-butadiene rubber (NBR), elastic rubber such as ethylene-propylene-diene terpolymer rubber (EPDM), sponge such as urethane foam, etc. Has a structure in which a conductive layer 3 is formed.
This developing roller forms the conductive layer 3 on the outer periphery of the shaft 2 and then, as shown in FIG.
It is manufactured by polishing.

[0006]

However, the above-mentioned conventional developing method has the following problems caused by the characteristics of the developing roller. That is, (1) in a developing roller having a conductive elastic layer formed of an elastic rubber such as silicone rubber, NBR, EPDM, or polyurethane resin on the outer periphery of the conductive shaft, no surface layer (coat layer) is provided on the outer periphery of the conductive elastic layer. When used in, the friction coefficient between the developing roller and the photosensitive drum or developing blade becomes large, and not only a large force is required for driving, but also the relative speed between the developing roller and the photosensitive drum becomes unstable, and the image becomes uneven. Cheap. Also,
(2) As a countermeasure of the above (1), there is a method of reducing a friction coefficient by forming a surface layer (coat layer) on the outer periphery of the conductive elastic layer. The toner cannot be sufficiently triboelectrically charged, causing image fogging. And the above (1), (2)
As a result, unevenness in density occurs in the obtained image, and thinning of characters occurs due to long-term use. This tendency is particularly remarkable in the pressure development method using a non-magnetic one-component toner.

The present invention has been made in view of the above circumstances, and in an electrophotographic apparatus such as a copying machine or a printer or an electrostatic recording apparatus, an electrostatic latent image held on a latent image holder such as a photosensitive drum is used. Electrostatic latent image development that eliminates the above-mentioned problems caused by the characteristics of the developing roller during development and can provide high-quality images without uneven image density, background fogging, and thinning of characters even after long use. It is an object to provide a method and a developing device.

[0008]

In order to achieve the above object, the present inventors have conducted intensive studies focusing on the surface condition of the developing roller. As a result, the conductive layer of the developing roller obtained through the surface polishing step has been obtained. The surface of the developing roller has minute ridge-shaped irregularities inclined in one circumferential direction of the developing roller, and the developing roller is rotated so that the inclination direction of the ridge-shaped irregularities and the rotation direction of the developing roller during development are opposite to each other. By arranging the irregularities and optimizing the shape and arrangement of the irregularities, it is possible to obtain a good friction coefficient and a sufficient frictional electrification, secure a sufficient amount of toner to be transported, and achieve a density unevenness even after long-time use. It was found that a high-quality image free of ground fogging, thinning of characters, etc. can be obtained.

That is, a developer is carried on the surface of a developing roller to form a thin layer of the developer, and the developing roller is brought into contact with a latent image holding member such as a photosensitive drum holding an electrostatic latent image on the surface. When the developer is supplied to the surface of the latent image holding member and the electrostatic latent image on the surface of the latent image holding member is visualized by rotating the developer in the state of being close to the surface, a minute fine particle formed on the surface of the developing roller is formed. Due to the ridge-shaped irregularities, a good friction coefficient and sufficient frictional charging on the developing roller can be obtained. In this case, the inclination direction of the ridge-shaped irregularities and the rotation direction of the developing roller are opposite. It is more convenient to obtain a good friction coefficient and sufficient triboelectric charging, and furthermore, the height of the irregularities is 0.1 to 30 μm, and the average interval between the convex portions along the circumferential direction is 1 to 500 μm. As a result, a wave streak along the axial direction is formed on the roller surface by the unevenness. The JIS 10 point average roughness Rz along the circumferential direction in the direction opposite to the inclination direction of the unevenness is 5 to 20 μm, and the JIS 10 point average roughness R along the axial direction.
JIS along the circumferential direction with z being 3 to 15 μm
By making the 10-point average roughness Rz larger than the JIS 10-point average roughness Rz along the axial direction and optimizing the shape of the unevenness on the roller surface, a sufficient amount of toner transport can be maintained for a long period of time. As a result, a high-quality image without density unevenness or background fog over a long period of time was obtained, and it was found that the above conventional problems could be effectively solved, and the present invention was accomplished. It is.

Accordingly, the present invention provides a developing roller having a conductive layer formed on the outer periphery of a highly conductive shaft, carrying a developing agent on the surface thereof to form a thin layer of the developing agent. By rotating the latent image holding member and the developing roller by contacting or approaching the drum-shaped latent image holding member holding the electrostatic latent image, a developer is supplied to the surface of the latent image holding member to supply the latent image to the latent image holding member. In a developing method for visualizing an electrostatic latent image on the surface of an image holding member, the developing roller has small fluff-like irregularities inclined in a circumferential direction, and the height of the irregularities is 0.
1 to 30 μm, and the average spacing between convex portions along the circumferential direction is 1
.About.500 .mu.m, and furthermore, a wave streak along the axial direction is formed on the roller surface by the unevenness, whereby the surface roughness of the roller is along the circumferential direction in the direction opposite to the inclination direction of the unevenness. JIS 10 point average roughness Rz is 5 to 20 μm,
JIS 10 point average roughness Rz along the axial direction is 3 to 15μ
m, and the JIS 10-point average roughness Rz along the circumferential direction is larger than the JIS 10-point average roughness Rz along the axial direction, and the inclination direction of the unevenness of the developing roller is the rotation direction of the developing roller. And a method for developing an electrostatic latent image, characterized by being arranged in the opposite direction, and a rotatable drum-shaped latent image holder capable of holding the electrostatic latent image on the surface,
A conductive roller formed on the outer periphery of the good-conductivity shaft; and a developing roller rotatably disposed in a state of being in contact with or close to the surface of the latent image holding member. Forming a thin layer of the developer by carrying the developer on the developing roller, and rotating the developing roller and the latent image holder in this state to supply the developer to the surface of the latent image holder. In the electrostatic latent image developing device for visualizing the electrostatic latent image on the surface of the latent image holding member, the developing roller has small fluff-shaped irregularities inclined in a circumferential direction, and the height of the irregularities is small. 0.1 to 30 μm, the average interval between the convex portions along the circumferential direction is 1 to 500 μm, and furthermore, the unevenness forms an axial streak on the roller surface,
As a result, the surface roughness of the roller becomes JIS 10-point average roughness R along the circumferential direction in the direction opposite to the inclination direction of the unevenness.
z is 5 to 20 μm, JIS10 point average roughness Rz along the axial direction is 3 to 15 μm, and JIS1 along the circumferential direction.
The zero point average roughness Rz is greater than the JIS ten point average roughness Rz along the axial direction, and the developing roller is disposed such that the inclination direction of the unevenness is opposite to the rotation direction of the developing roller. And a developing device for an electrostatic latent image.

Hereinafter, the present invention will be described in more detail.
As described above, the developing method and the developing device of the present invention use the developing roller having the rugged irregularities on the surface, and the inclination direction of the rugged irregularities on the surface of the developing roller is opposite to the rotation of the developing roller. The developing is performed in a state where the developing rollers are arranged in the same direction. For example, as shown in FIG. 1, a drum-shaped latent image holding member (photosensitive drum) holding an electrostatic latent image on the surface as shown in FIG. The developing roller 1 is disposed between the developing roller 1 and the toner coating roller 4, and the developing roller 1 is set so that the inclination direction of the unevenness 10 on the surface thereof is opposite to the rotation direction of the developing roller 1. Set the developing roller 1
Is rotated to transfer toner (developer) from the toner applying roller 4 through the developing roller 1 to the photosensitive drum 5.
To visualize the electrostatic latent image on the surface of the photosensitive drum 5.

As shown in FIG. 1, the developing roller 1 has a conductive layer 3 formed on the outer periphery of a good conductive shaft 2. Here, the shaft 2 is not particularly limited as long as it has good conductivity, but is not particularly limited. Usually, a metal core such as a metal core or a metal hollow cylinder is used. A metal shaft is preferably used.

When the photosensitive drum 5 and the developing roller 1 are not in contact with each other, the conductive layer 3 has a metal shaft 2.
A mixture of various resins mixed with conductive powder, magnetic powder, etc., or a conductive resin, etc. laminated and polished on the surface can be used. If the photoconductor contacts the developing roller, the developing nip For this reason, a relatively soft elastic body is used. The base component of the conductive layer 3 is not particularly limited, but is preferably an elastomer such as conductive rubber or polyurethane, or a foam material. Therefore, it is preferable to use a polyurethane resin.

As the conductive rubber, non-foamed conductive rubbers such as nitrile butadiene rubber, natural rubber, butyl rubber, nitrile rubber, isoprene rubber, polybutadiene rubber, silicone rubber, styrene-butadiene rubber,
Ordinary rubber such as ethylene-propylene rubber, ethylene-propylene-diene terpolymer rubber (EPDM), chloroprene rubber, acrylic rubber, polynorbornene rubber, or styrene-butadiene-styrene (SBS), styrene-butadiene-styrene water Thermoplastic rubbers such as additives (SEBS) and mixtures thereof can be mentioned. Further, as a foamed conductive rubber, ethylene-propylene-diene terpolymer rubber (EPDM), chloroprene rubber, chlorosulfonated polyethylene blended with a conductive material, epichlorohydrin, a foam of a copolymer rubber of ethylene oxide or A foam obtained by blending a conductive material with a copolymer rubber of epichlorohydrin and ethylene oxide may be used.

Examples of the conductive material to be incorporated into these rubber compositions include powdery conductive materials such as conductive carbon such as Ketjen Black EC and acetylene black;
F, ISAF, HAF, FEF, GPF, SRF, F
Rubber carbon such as T, MT, etc., carbon for color (ink) which has been subjected to oxidation treatment, pyrolytic carbon, natural graphite, artificial graphite, antimony-doped tin oxide, titanium oxide, zinc oxide, nickel, copper, silver, Examples include metals and metal oxides such as germanium, and conductive polymers such as polyaniline, polypyrrole, and polyacetylene. The compounding amount can be 3 to 100 parts by weight, particularly 5 to 50 parts by weight, based on 100 parts by weight of the total rubber component, whereby the volume resistivity of the conductive layer 3 is 10 ³ to It can be adjusted to 10 ¹⁰ Ω · cm.

The polyurethane foam or elastomer for forming the conductive layer 3 may be any of polyurethane foams and elastomers produced by various methods. For example, carbon black is blended in a polyurethane prepolymer, and this prepolymer is crosslinked. A method obtained by, for example, a method of reacting, mixing a conductive material with a polyol, and reacting the polyol with a polyisocyanate by a one-shot method can be suitably used.

Specifically, as the urethane, as a polyhydroxyl compound, polyols used in the production of general flexible polyurethane foams and urethane elastomers, for example, polyether polyols and polyester polyols having a polyhydroxyl group at a terminal, and both of them. In addition to polyester polyether polyols that are copolymers, general polyols such as polyolefin polyols such as polybutadiene polyol and polyisoprene polyol, and so-called polymer polyols obtained by polymerizing ethylenically unsaturated monomers in polyols Can be used. Similarly, as the polyisocyanate compound, polyisocyanates used for producing general flexible polyurethane foams and urethane elastomers, that is, tolylene diisocyanate (TDI), crude TDI, 4,4-diphenylmethane diisocyanate (MDI), Crude MDI, aliphatic polyisocyanate having 2 to 18 carbon atoms, alicyclic polyisocyanate having 4 to 15 carbon atoms, and mixtures and modified products of these polyisocyanates, for example, prepolymers obtained by partially reacting with polyols Are used.

Examples of the conductive material to be added to these polyurethanes include the same conductive materials as those used in the rubber composition, and inorganic ionic substances such as lithium perchlorate and sodium perchlorate, and quaternary ammonium salts. Conductive materials consisting of various organic ionic substances, cationic surfactants, anionic surfactants, amphoteric surfactants such as various betaines, and nonionic antistatic agents such as hydrophilic polyethers and polyesters And the like, and these can be used alone or in combination of two or more. The compounding amount may be adjusted so as to have an appropriate resistance value depending on the type of the conductivity-imparting substance.
The amount can be 0.5 to 50 parts by weight, particularly 1 to 30 parts by weight, based on 0 parts by weight, whereby the volume resistivity of the conductive layer 3 can be adjusted to 10 ³ to 10 ¹¹ Ω · cm. . In addition, an electron accepting substance capable of forming a charge transfer complex such as tetracyanoethylene, tetracyanoquinodimethane, benzoquinone, chloranil, anthraquinone, anthracene, dichlorodicyanobenzoquinone, ferrocene, or phthalocyanine can be blended as a conductive material. In this case, the compounding amount is 0.1 part with respect to 100 parts by weight of urethane.
It can be 001 to 20 parts by weight, especially 0.01 to 1 part by weight.

Here, in particular, the developing roller 1 is connected to the photosensitive drum 5
When the development is carried out by contacting the conductive layer 3, the hardness of the conductive layer 3 is preferably 60 ° or less, particularly preferably 10 to 55 ° on a JIS-A scale, though not particularly limited.
In this case, if the hardness exceeds 60 °, the contact area with the photosensitive drum or the like becomes small, and good development may not be performed. On the other hand, if the hardness is too low, the compression set becomes large, and the developing roller Is deformed or decentered, image density unevenness occurs. Therefore, even when the hardness of the elastic layer is low, it is preferable to reduce the compression set as much as possible. Specifically, it is preferable to adjust the compression set so that the compression set is 20% or less.

According to the developing method of the present invention, minute bumpy irregularities 10 are formed on the surface of the conductive layer 3. These irregularities can be easily formed by polishing the surface of the conductive layer 3. In this case, generally, there is a polishing method such as a wet method or a dry method, but in the present invention, the dry method is particularly preferably used. Specifically, as shown in FIG. 2, the developing roller 1 is rotated at about 100 rpm, and the grindstone 11 is brought into contact with the surface of the conductive layer 3 of the developing roller 1, and the grindstone 11 is rotated in the opposite direction at about 1500 rpm. By moving the developing roller 1 from one end side to the other end side while rotating at a speed, polishing can be performed to form irregularities. In this case, the entire surface of the developing roller 1 can be polished at once without moving with a wider grindstone. The concavities and convexities obtained by polishing in this way are
In the direction of rotation of the developing roller 1, that is, in the circumferential direction of the developing roller 1. In addition, it is also possible to use a polishing method by a wet method of polishing while spraying a lubricant such as water or oil between the grindstone and the conductive layer. May be formed, and a method of injecting a conductive layer forming material into the developing roller to form a developing roller (such as an injection molding method) may be used. The unevenness of the surface of the conductive layer 3 is not particularly limited, but the height of the unevenness is 0.1 to 30 μm, and the average interval between the convex portions along the circumferential direction of the roller is 1 to 500 μm.

The roughness of the surface of the developing roller on which the embossed irregularities are formed by the above-described polishing method or the like is determined by the JIS 10-point average roughness Rz in the circumferential direction of the roller (the direction opposite to the inclination of the irregularities).
Are formed larger than those in the axial direction. Specifically, the circumferential direction Rz is 5 to 20 μm, and the axial direction Rz is 3 to 15 μm. By adjusting the surface roughness Rz in this way,
A more stable toner transport amount can be ensured, and the occurrence of image unevenness or the like can be more reliably prevented over a long period of time. The measurement of the surface roughness Rz is performed as follows as shown in FIG. That is, the JIS 10 point average roughness Rz in the circumferential direction of the developing roller can be obtained by sweeping the surface of the conductive layer 3 with a contact type surface roughness meter in the direction of (1) in FIG. The point average roughness Rz is represented by (2) in FIG.
, Ie, at a right angle to the direction of (1).

As shown in FIG. 1, the developing method and the developing device according to the present invention are arranged such that the direction of inclination of the unevenness 10 on the surface thereof is opposite to the direction of rotation of the developing roller 1. By doing so, the developer held on the surface of the developing roller 1 is supplied to the latent image holding member 5 to develop the electrostatic latent image on the surface of the latent image holding member 5, whereby the density of the electrostatic latent image is maintained for a long time. A high-quality image without unevenness, ground cover, thinning of characters, etc. can be obtained. In this case, the developer may be either a magnetic or non-magnetic one-component developer, and the effect of the present invention is particularly remarkable when a non-magnetic one-component developer is used. When the developing roller 1 is rotated in a non-contact state with the latent image holding member 5, the distance between the surface of the developing roller 1 and the surface of the latent image holding member 5 is 50 to 500 μm, particularly 100 to 30 μm.
Preferably, the thickness is about 0 μm. Further, the developing roller 1
The rotation direction of the developing roller 1 and the toner coating roller 4 may be the same or opposite to each other, and may be arbitrarily set according to various conditions.

Other conditions such as the latent image holding member 5 other than the developing roller 1 constituting the developing process, members such as the toner coating roller 4 and the rotation speed of each roller can be set to normal conditions.

[0024]

As described above, according to the developing method and apparatus of the present invention, minute ridge-like irregularities are formed on the surface of the developing roller, and the inclination direction of the irregularities and the rotation direction of the developing roller. Is set to be in the opposite direction, it is possible to obtain a good friction coefficient and sufficient triboelectric charging, and to obtain high-quality images without density unevenness, Obtainable.

[0025]

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 The following components were stirred and mixed, poured into a mold heated to 110 ° C., and cured for 2 hours to form a conductive layer on the outer periphery of a metal shaft to obtain a developing roller. Was. The surface of the obtained roller was dry-polished, and the surface condition was observed with an electron microscope. As shown in the reference photograph (electron micrograph [500 times]), the surface of the conductive layer had waves due to minute irregularities. The pattern was confirmed. Furthermore, similarly, by oblique observation from the A direction and the B direction of the reference photograph, it is found that this wavy pattern is caused by unevenness of a fluffy shape, and the unevenness is inclined in the A direction (one circumferential direction of the roller) of the reference photograph. It was confirmed that.

Ingredients of Conductive Layer : Polyether polyol (OH value: 33) having a molecular weight of 5,000 by adding propylene oxide and ethylene oxide to glycerin (Exenol 828, manufactured by Asahi Glass Co., Ltd.) 100 weight Part: urethane-modified MDI NCO% = 23% (manufactured by Sumitomo Bayer Urethane Co., Ltd., trade name: Sumidur PF) 25.0 parts by weight ・ 1,4-butanediol 2.5 parts by weight ・ dibutyltin dilaurate 0.01 Parts by weight ・ 33% diethylene glycol monomethyl ether solution of sodium perchlorate 0.2 parts by weight

Next, the obtained roller is used as the developing roller 1 and the direction A of the reference photograph (the inclination direction of the unevenness of the roller surface) is opposite to the rotation direction of the developing roller 1 in the developing unit shown in FIG. (A reverse direction), using a non-magnetic one-component toner having an average particle diameter of 7 μm, and a linear velocity of 60 mm /
An image was formed by reversal development while rotating at a peripheral speed of sec, and the image quality, image density, toner conveyance amount, and toner charge amount at the initial stage and after 10,000 prints were evaluated.

Example 2 The following components were stirred and mixed, poured into a mold heated to 110 ° C., and cured for 2 hours to form a conductive layer on the outer periphery of a metal shaft to obtain a developing roller. Was. The surface of the obtained roller was dry-polished, and the surface state was observed with an electron microscope. As a result, the same unevenness as in Example 1 was confirmed on the surface of the conductive layer.

Ingredients of the Conductive Layer : Polyether polyol (OH value 33) (trade name: Exenol 828, manufactured by Asahi Glass Co., Ltd.) having a molecular weight of 5,000 by adding propylene oxide and ethylene oxide to glycerin was added to the tri-layer. 100 parts by weight of polyether prepolymer prepolymerized with range isocyanate (TDI-80, NCO% = 23% (manufactured by Sumitomo Bayer Urethane Co., Ltd.)) Asahi Thermal FT grade (manufactured by Asahi Carbon Co., Ltd.) 3 0.0 parts by weight ・ 1,4-butanediol 6.9 parts by weight ・ Dibutyltin dilaurate 0.05 parts by weight ・ Quaternary ammonium salt (manufactured by Kao Corporation, KS-555) 0.2 parts by weight

Using the above-mentioned roller, it was mounted on the developing unit in the same manner as in Example 1, and the same evaluation was performed. Example 1 above,
Table 1 summarizes the evaluation results obtained in Step 2. The measuring method for each evaluation is shown below.

The average roughness Rz was measured by using a surface roughness meter Surfcom Model 570A (manufactured by Tokyo Seimitsu Co., Ltd.) for each roller and sweeping in the A and B directions of the reference photograph along the circumferential direction of the roller. did. The interval between the corrugations (interval between the convex portions) of each of the irregularities was calculated based on an electron micrograph. The height of the unevenness was calculated from the cross-sectional curve obtained by the measurement of the average roughness Rz. Hardness For each sheet-shaped sample created under the same conditions as each roller. It was measured according to JIS-K6301 (A type). Image Density The image density of the specified portion (9 points) of the solid black image was measured with a Macbeth densitometer RD918122. Each roller of the toner charge amount is attached to the developing unit shown in FIG. 1 as a developing roller, and is rotated at a peripheral speed of 50 mm / sec to form a uniform thin toner layer on the surface of the developing roller. And introduced into a Faraday gauge, and the charge amount was measured. Toner transfer amount A uniform thin toner layer is formed on the roller in the same manner as the above toner charge amount, and the thin toner layer is sucked with a constant area of air,
It was determined by measuring its weight. Image quality By visually observing an image sample (solid black, halftone, character) obtained by taking out an image under the above conditions,
The sharpness, density unevenness, fog and the like were evaluated.

[0033]

[Table 1]

From the results shown in Table 1, according to the developing method and apparatus of the present invention, a sufficient amount of toner having a sufficient charge amount can be supplied to the photosensitive member over a long period, and a sufficient image can be provided over a long period. It was confirmed that a high-quality image having a density could be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a developing method and apparatus of the present invention.

FIG. 2 is a schematic view showing an example of a method for polishing a developing roller used in the developing method and apparatus of the present invention.

FIG. 3 is a schematic diagram illustrating a direction in which the surface roughness of a developing roller used in the developing method and apparatus of the present invention is measured.

FIG. 4 is a schematic sectional view of a developing roller used in a conventional developing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Developing roller 2 Shaft 3 Conductive layer 4 Toner application roller 5 Photosensitive drum (latent image holding body) 6 Developing blade 7 Transfer roller 8 Cleaning unit 9 Cleaning blade 10 Unevenness 11

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-175476 (JP, A) JP-A 62-53453 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 13/08-13/095 G03G 15/08-15/095

Claims (4)

(57) [Claims] 1. A thin layer of a developer is formed by carrying a developer on the surface of a developing roller having a conductive layer formed on the outer periphery of a good conductive shaft. The developer is supplied to the surface of the latent image holding member by rotating the latent image holding member and the developing roller in contact with or in proximity to the drum-shaped latent image holding member holding the surface of the latent image holding member. In the developing method for visualizing an electrostatic latent image of (1), the developing roller has small fluff-shaped irregularities inclined in one circumferential direction, and the height of the irregularities is 0.1 to 3
0 μm, and the average interval between the convex portions along the circumferential direction is 1 to 50
0 μm, and furthermore, a wave streak along the axial direction is formed on the roller surface by the unevenness, whereby the surface roughness of the roller is reduced in accordance with JIS 10 in the circumferential direction opposite to the inclination direction of the unevenness. The point average roughness Rz is 5 to 20 μm, the JIS 10 point average roughness Rz along the axial direction is 3 to 15 μm,
In addition, the JIS 10-point average roughness Rz along the circumferential direction is larger than the JIS 10-point average roughness Rz along the axial direction, and the inclination direction of the unevenness is opposite to the rotation direction of the development roller. A method for developing an electrostatic latent image, wherein 2. The method for developing an electrostatic latent image according to claim 1, wherein the developing roller has a small unevenness formed by polishing the surface of the conductive layer. 3. The method for developing an electrostatic latent image according to claim 1, wherein the developer is a non-magnetic one-component developer. 4. A rotatable drum-shaped latent image holding member capable of holding an electrostatic latent image on a surface thereof, and a conductive layer formed on the outer periphery of a good conductive shaft. A developing roller rotatably disposed in contact with or in proximity to the developing roller. The developer is carried on the surface of the developing roller to form a thin layer of the developing agent. And rotating the latent image holding member to supply a developer to the surface of the latent image holding member to visualize the electrostatic latent image on the surface of the latent image holding member. The developing roller has small unevenness in the shape of a bulge inclined in the circumferential direction, and the height of the unevenness is 0.1 to 3
0 μm, and the average interval between the convex portions along the circumferential direction is 1 to 50
0 μm, and furthermore, a wave streak along the axial direction is formed on the roller surface by the unevenness, whereby the surface roughness of the roller is reduced in accordance with JIS 10 in the circumferential direction opposite to the inclination direction of the unevenness. The point average roughness Rz is 5 to 20 μm, the JIS 10 point average roughness Rz along the axial direction is 3 to 15 μm,
In addition, the JIS 10-point average roughness Rz along the circumferential direction is larger than the JIS 10-point average roughness Rz along the axial direction, and the inclination direction of the unevenness is opposite to the rotation direction of the development roller. A developing device for an electrostatic latent image, wherein the developing device is arranged such that: