JP6040776B2 - Developing roller surface processing method, developing roller, developing device, and process cartridge - Google Patents

Description

  The present invention relates to a developing roller surface processing method, a developing roller, a developing device, and a process cartridge.

Conventionally, in electrophotography, the electrostatic latent image formed by charging and exposing the surface of a photoreceptor is developed with a colored toner to form a toner image, and the toner image is transferred to a transfer medium such as transfer paper. This is fixed with a heat roll or the like to form an image.
Dry development methods employed in electrophotography, electrostatic recording, and the like include a method using a two-component developer composed of a toner and a carrier, and a method using a one-component developer not containing a carrier.

  The former method provides a relatively stable and good image, but it is difficult to obtain a constant quality image over a long period of time because carrier deterioration and a change in the mixing ratio of toner and carrier are likely to occur. In addition, there are difficulties in maintaining and managing the apparatus and making it compact. Therefore, a method using the latter one-component developer that does not have such drawbacks has been used.

  In this one-component development system, toner is held on a developing roller, which is a toner conveying member, and the held toner is pressed by a regulating member to adjust the toner charge and layer thickness. However, since the one-component developing method is a developing method that applies a great deal of stress to the toner, it is often incompatible with the low-temperature fixing toner that has been a trend in recent years. Tend.

  Since toner adhesion and filming are improved by improving the flow of toner at the restricting portion, the shape pattern on the surface of the developing roller has been studied, but the material is metal or heat for ease of processing. Limited to materials such as curable elastomers.

  For example, a developing rubber roller for contact one-component development has a complicated fine structure due to a technique for forming irregularities on the surface by means such as polishing or filler addition, laser processing, etc. for the purpose of improving toner transportability and resetability. A technique for imparting unevenness, a technique for forming regions of different hardness in a pattern by electron beam irradiation (for example, see Patent Document 1), and the like are known.

  Patent Document 1 discloses a conductive roller in which low molecular weight components in the conductive vulcanized rubber layer can suppress the bleeding to the surface of the conductive rubber roller while suppressing an increase in the hardness of the conductive vulcanized rubber layer. As a manufacturing method, the peripheral surface of the conductive vulcanized rubber layer formed around the core metal is irradiated with an electron beam through a mask member in which portions having different electron beam transmittances are arranged in a pattern, A method is disclosed in which regions of different hardness derived from differences in electron beam irradiation intensity are formed in a pattern on the surface of a conductive vulcanized rubber layer.

  As a method of forming a pattern on the surface of the developing roller, in conventional laser processing, fine processing on the order of microns can be performed by irradiating laser using a photomask having a fine pattern. There is a problem that the maintenance cost of the noble gas for performing laser oscillation is very high and the processing time becomes long, so that the amount that can be processed is small and the cost is high.

  In addition, there has been a problem that the electrical property of the rubber roller is greatly changed due to the progress of oxidation of the surface of the rubber roller due to the effect of thermal melting or ablation by the laser.

  The method described in Patent Document 1 has the same problem, and it is difficult to provide a vulcanized rubber layer with a complicated and fine shape without an oxide film at low cost.

  In view of the above problems, an object of the present invention is to provide a developing roller surface processing method capable of forming a fine shape at low cost without changing electrical characteristics.

  In order to solve the above-described problems, the developing roller surface processing method according to the present invention regulates the thickness of the developing roller that holds toner on the outer peripheral surface and transports it to the developing region, and the thickness of the toner layer supplied to the developing roller. A method of processing a surface of the developing roller of a one-component developing device comprising at least a regulating member, wherein the vulcanized rubber layer constituting the surface of the developing roller is pressed and compressed and deformed in the thickness direction; A developing roller surface processing method comprising: performing a plasma treatment in a compressed and deformed state; and releasing a pressure to form an uneven structure on a surface.

  According to the developing roller surface processing method of the present invention, it is possible to provide a developing roller surface processing method capable of forming a fine shape at low cost without changing electrical characteristics.

It is a schematic diagram showing an example of the surface of the developing roller processed by the developing roller surface processing method of the present embodiment. It is sectional drawing which shows an example of the image development apparatus of this embodiment. It is sectional drawing which shows an example of the process cartridge of this embodiment.

  A developing roller surface processing method, a developing roller, a developing device, and a process cartridge according to the present invention will be described below with reference to the drawings. It should be noted that the present invention is not limited to the embodiments of the examples shown below, and other embodiments, additions, modifications, deletions, and the like can be changed within a range that can be conceived by those skilled in the art. Any aspect is included in the scope of the present invention as long as the operations and effects of the present invention are exhibited.

[Development roller surface processing method and development roller]
The developing roller surface processing method according to the present embodiment includes at least a developing roller that holds toner on an outer peripheral surface and conveys the toner to a developing region, and a regulating member that regulates the thickness of the toner layer supplied to the developing roller. A method of processing a surface of the developing roller of a one-component developing device, the step of applying pressure to the vulcanized rubber layer constituting the surface of the developing roller to compressively deform in the thickness direction, and the plasma treatment in the state of compressive deformation And a step of releasing pressure and forming an uneven structure on the surface.

  By irradiating the plasma in a state where the vulcanized rubber layer constituting the surface of the developing roller is stretched, the rubber hardness of the micro area irradiated with the plasma is increased. When the pressure is released from this state to cause contraction, it becomes possible to impart a fine uneven structure shape of the order of several μm due to the influence of the hardness difference.

An example of the uneven structure on the surface of the developing roller of this embodiment is shown in FIG.
FIG. 1 is an enlarged schematic view of the concavo-convex structure on the surface of the developing roller of this embodiment.
As shown in FIG. 1, the formed concavo-convex structure is, for example, a ridge-like structure with a convex portion having a width of 0.1 to 1 μm. The concavo-convex structure to be formed is not limited to a ridge-like structure in which convex ridges and concave valleys are alternately present as shown in FIG. It is formed.

  On the surface of the developing roller on which the fine concavo-convex structure as described above is formed, the toner flow is improved and the toner adhesion to the developing roller can be reduced, so that the toner filming property is improved.

  In the step of pressurizing the vulcanized rubber layer and compressively deforming in the thickness direction, the pressurizing linear pressure is preferably 100 to 250 N / m.

  In the step of performing the plasma treatment in a state where the vulcanized rubber layer is compressed and deformed, the time for performing the plasma irradiation is preferably 10 to 30 seconds.

  The plasma treatment is preferably performed using a non-reactive gas, and examples of the non-reactive gas include He and Ar.

  By performing the plasma treatment while applying pressure to the vulcanized rubber layer as described above, the crosslink density in the micro region of the surface is improved. This reaction is not accompanied by a state change such as thermal melting or molecular cutting as in laser processing, and thus adverse effects such as formation of an oxide film on the surface are unlikely to occur.

  The surface processing method of this embodiment comprises only a step of releasing the pressure after irradiating the surface of the vulcanized rubber layer deformed (elongated) by pressurization, and also suppresses the formation of an oxide film associated with the reaction. Therefore, it is a simple and very productive processing method.

  The developing roller 13 includes, for example, a shaft core, a vulcanized rubber layer on the outer periphery of the shaft core, and a surface layer having a concavo-convex structure processed by the surface processing method of the present embodiment on the outer peripheral surface of the vulcanized rubber layer. And other layers as necessary. For example, you may have a surface coat layer in the outermost surface.

The vulcanized rubber layer preferably contains an epichlorohydrin rubber selected from an epichlorohydrin-ethylene oxide copolymer and an epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer.
The vulcanized rubber layer may contain a conductive agent, a foaming agent, a crosslinking agent, a crosslinking accelerator, an oil, and the like as appropriate.

  The developing roller 13 can be manufactured as follows, for example. First, components constituting the vulcanized rubber layer are kneaded with a kneader such as a kneader and cast into a gap between a metal shaft core (core metal) and a cylindrical mold. Next, the upper lid is fitted on a cylindrical mold, and the entire roller mold is heated and vulcanized (150 ° C. to 220 ° C. × 20 minutes), and then removed from the roller mold to form a vulcanized rubber layer. The outer peripheral surface of the vulcanized rubber layer thus formed is processed by the surface processing method of the present embodiment to form a concavo-convex structure.

  The developing roller 13 is set to a hardness of 60 degrees or less according to JIS-A in order to prevent toner deterioration due to pressure concentration at the contact portion with the regulating member 15. Further, since a developing bias is applied to the developing roller 13 to form an electric field between the developing roller 13 and the image carrier (photosensitive member) 11, the intermediate layer is set to have a resistance value of 103Ω to 1010Ω.

  The shaft core is not particularly limited, and can be appropriately selected from carbon steel, alloy steel, cast iron, conductive resin, and the like. Here, examples of the alloy steel include stainless steel, nickel chromium steel, nickel chromium molybdenum steel, chromium steel, chromium molybdenum steel, nitriding steel to which Al, Cr, Mo, and V are added. Therefore, those made of metal are preferable. Further, the shaft core material can be plated and oxidized as a rust prevention measure. Any of electroplating and electroless plating can be used as the type of plating, but electroless plating is preferred from the viewpoint of dimensional stability.

  The vulcanized rubber layer can be provided with predetermined conductivity by adding a conductive agent such as an ionic conductive agent or an electronic conductive agent. Examples of the ionic conductive agent include perchlorine such as tetraethylammonium, tetrabutylammonium, lauryltrimethylammonium, dodecyltrimethylammonium, stearyltrimethylammonium, octadecyltrimethylammonium, hexadecyltrimethylammonium, benzyltrimethylammonium, and modified aliphatic dimethylethylammonium. Such as acid salt, chlorate, hydrochloride, bromate, iodate, borofluoride, sulfate, alkyl sulfate, carboxylate, sulfonate, ammonium salt, PF6 salt, BF4 salt, etc. Perchlorates, chlorates, hydrochlorides, bromates, iodates, borofluorides of alkali metals or alkaline earth metals (eg lithium, sodium, calcium, magnesium, etc.) Periodate, trifluoromethyl sulfate, sulfonate, PF6 @ salts, and the like BF4 salt. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the electronic conductive agent include various conductive metals or alloys such as carbon black, graphite, aluminum, copper, nickel, and stainless steel; tin oxide, indium oxide, titanium oxide, zinc oxide, tin oxide-antimony oxide composite oxide And various conductive metal oxides such as tin oxide-indium oxide composite oxide; those obtained by conducting the surface of an insulating material. These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular as addition amount of the said electrically conductive agent, According to the objective, it can select suitably according to various conditions, and in the case of an ionic conductive agent, 0.01 mass with respect to 100 mass parts of rubber | gum. Part-5 mass parts is preferable, and 0.05 mass part-2 mass parts is more preferable. In the case of an electronic conductive agent, 0.5 to 50 parts by mass is preferable with respect to 100 parts by mass of rubber, and 1 to 40 parts by mass is more preferable.

Moreover, after apply | coating the coating liquid prepared suitably to the outer peripheral surface surface-processed, a surface coat layer can be formed by performing drying and heat processing.
The method for applying the coating liquid is not particularly limited, and conventional methods such as a dipping method, a spray method, and a roller coating method can be applied.

[Development equipment]
The developing device of this embodiment includes at least the developing roller and a regulating member that regulates the thickness of the toner layer supplied to the developing roller, and further includes other members as necessary.

FIG. 2 shows a cross-sectional view of the developing device and the image carrier of this embodiment.
A developing roller 13 as a toner conveying member of the developing device 12 contacts the image carrier 11 or holds a gap of about 0.1 μm to 0.3 μm, and is driven in the arrow direction in the figure. The image carrier 11 rotates in the direction of the arrow in the figure.
A supply roller 14 around the developing roller 13, a rubber plate (for example, urethane rubber, silicone rubber, etc.) attached to a leaf spring material, or a restriction member that is a metal-made restriction blade (toner layer thickness restriction blade) such as SUS 15 is arranged.
In addition, a toner feed shaft 16 is rotatably disposed in a holding chamber 17 that holds toner for supplying toner to the toner supply roller 14.
The developing roller 13 rotates in the clockwise direction, and conveys the toner held on the surface to a position facing the regulating member 15 and the image carrier 11.

  The regulating member 15 is provided at a position lower than the contact position between the supply roller 14 and the developing roller 13. The regulating member 15 is made of a metal leaf spring material such as stainless steel (SUS) or phosphor bronze, and the free end side is brought into contact with the surface of the developing roller 13 with a pressing force of 10 N / m to 40 N / m. The toner that has passed under the pressure is thinned and an electric charge is applied by triboelectric charging. Further, in order to assist frictional charging, a regulating bias having a value offset in the same direction as the toner charging polarity is applied to the regulating member 15.

[Process cartridge]
The process cartridge of this embodiment has at least an image carrier and a developing unit that develops an electrostatic latent image with toner on the image carrier to form a visible image, and is detachable from the image forming apparatus main body. In a certain process cartridge, the developing means is the developing device of the present embodiment.

FIG. 3 shows a cross-sectional view of the process cartridge of this embodiment.
As shown in FIG. 3, the process cartridge incorporates an image carrier 11 and includes a charging unit 22, a developing unit (developing device) 12, a transfer unit 28, and a cleaning unit 27, and further includes other units as necessary. Have.

  Referring to the image forming process using the process cartridge shown in FIG. 3, the image carrier 11 is turned into an exposure image on the surface thereof by rotation by the charging means 22 and exposure 23 by the exposure means (not shown) while rotating in the direction of the arrow. A corresponding electrostatic latent image is formed. The electrostatic latent image is developed by the developing unit 12, and the obtained visible image is transferred to the recording medium 25 by the transfer unit 28 and printed out. Next, the surface of the image bearing member after the image transfer is cleaned by the cleaning unit 27, further neutralized by the neutralizing unit (not shown), and the above operation is repeated again.

  The material, shape, structure, size and the like of the image carrier 11 are not particularly limited and can be appropriately selected according to the purpose. Examples of the shape include a drum shape, a sheet shape, and an endless shape. Examples include a belt shape. The structure may be a single-layer structure or a laminated structure, and the size may be appropriately selected according to the size and specifications of the image forming apparatus. Examples of the material include inorganic photoreceptors such as amorphous silicon, selenium, CdS, and ZnO; organic photoreceptors (OPC) such as polysilane and phthalopolymethine, and the like.

  For example, the amorphous silicon photosensitive member is heated at 50 ° C. to 400 ° C., and a vacuum deposition method, a sputtering method, an ion plating method, a thermal CVD method, a photo CVD method, a plasma CVD method, or the like is applied on the support. A photosensitive layer made of a-Si is formed by the film forming method. Among these, the plasma CVD method is particularly preferable, and specifically, a method in which the source gas is decomposed by direct current, high frequency, or microwave glow discharge to form a photosensitive layer made of a-Si on the support is preferable. .

The organic photoreceptor (OPC) has (1) optical characteristics such as a wide light absorption wavelength range and a large amount of light absorption, (2) electrical characteristics such as high sensitivity and stable charging characteristics, (3) In general, it is widely applied because of the wide selection range of materials, (4) ease of production, (5) low cost, and (6) non-toxicity. The layer structure of such an organic photoreceptor is roughly divided into a single layer structure and a laminated structure.
The single-layer image carrier comprises a support and a single-layer type photosensitive layer on the support, and further comprises a protective layer, an intermediate layer and other layers as necessary.
The laminated image carrier comprises a support, and a laminated photosensitive layer having at least a charge generation layer and a charge transport layer in this order on the support, and further, if necessary, a protective layer, an intermediate layer It has a layer and other layers.

The charging means 22 is not particularly limited as long as it can apply a voltage to the surface of the image carrier 11 to be uniformly charged, and can be appropriately selected according to the purpose. (1) There are roughly divided into a contact-type charging means for charging in contact with the image carrier and (2) a non-contact-type charging means for charging in a non-contact manner with the image carrier.
Examples of the contact type charging means (1) include a conductive or semiconductive charging roller, a magnetic brush, a fur brush, a film, and a rubber blade. Among these, the charging roller can greatly reduce the amount of ozone generated compared to corona discharge, and is excellent in stability when the image carrier is repeatedly used, and is effective in preventing image quality deterioration.
The non-contact charging means (2) includes, for example, a non-contact charger using a corona discharge, a needle electrode device, a solid discharge element; a conductive or semi-conductive element disposed with a minute gap with respect to the image carrier. Examples thereof include a conductive charging roller.

The exposure indicated by 23 in FIG. 3 can be performed, for example, by exposing the surface of the image carrier 11 imagewise using the exposure means.
Optical systems that perform exposure are roughly classified into analog optical systems and digital optical systems. The analog optical system is an optical system that directly projects an original onto an image carrier by an optical system, and the digital optical system is supplied with image information as an electrical signal, and converts the image information into an optical signal to convert the image carrier to an image carrier. Is an optical system that exposes and forms an image.
The exposure means is not particularly limited as long as it can expose the surface of the image carrier 11 charged by the charging means 22 like an image to be formed, and can be appropriately selected according to the purpose. Examples include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, a liquid crystal shutter optical system, and an LED optical system.

The transfer unit 28 preferably has at least a transfer unit that peels and charges the visible image formed on the image carrier 11 toward the recording medium. The number of transfer means 28 may be one, or two or more.
The recording medium is not particularly limited and can be appropriately selected from known recording media (recording paper).

  The cleaning unit 27 is not particularly limited, and may be selected from known cleaners as long as it can remove the toner remaining on the image carrier 11. For example, a magnetic brush cleaner, electrostatic A brush cleaner, a magnetic roller cleaner, a blade cleaner, a brush cleaner, a web cleaner and the like are preferable.

〔Example〕
Examples of the present invention will be described below, but the present invention is not limited to these examples.

<Example 1>
Epichlorohydrin rubber Hydrin T3106 manufactured by Nippon Zeon Co., Ltd. was extruded on the outer periphery of a 6 mm diameter metal shaft to a thickness of 3 mm. Then, after vulcanizing by storing for 90 minutes in an environment of 150 ° C., the surface was roughly polished with a polishing machine LEO600-F4L-BME manufactured by Mizuguchi Seisakusho. Thereafter, finish polishing was performed with SZC manufactured by Mizuguchi Seisakusho to obtain a developing roller base material on which a vulcanized rubber layer was formed.

  Next, Ar plasma was irradiated for 10 seconds in a state where a 300 mm × 500 μm slit was pressed against the developing roller substrate with a linear pressure of 100 N / m. Then, the uneven | corrugated structure was formed in the surface by canceling | releasing the press-contact (pressurization) of a slit in normal atmosphere.

  Next, 2.5 parts by weight of Mitsui Chemicals Polyurethane Isocyanate D170N and Ketjen Black EC Ketjen Black EC 0.03 part by weight are added to 100 parts by weight of butyl acetate. A coating solution was prepared by stirring for 30 minutes. The obtained coating liquid was impregnated with a developing roller base material that had been subjected to surface processing, and further baked at 150 ° C. for 2 hours to obtain a developing roller.

<Example 2>
A developing roller of Example 2 was obtained in the same manner as in Example 1 except that the linear pressure for pressing the slit was 150 N / m.

<Example 3>
A developing roller of Example 3 was obtained in the same manner as in Example 1 except that the linear pressure at which the slit was pressed was 200 N / m.

<Example 4>
A developing roller of Example 4 was obtained in the same manner as in Example 1 except that the Ar plasma irradiation time was 20 seconds.

<Example 5>
A developing roller of Example 5 was obtained in the same manner as Example 1 except that the plasma was nitrogen plasma.

<Comparative Example 1>
Epichlorohydrin rubber Hydrin T3106 manufactured by Nippon Zeon Co., Ltd. was extruded on the outer periphery of a 6 mm diameter metal shaft to a thickness of 3 mm. Then, after vulcanizing by storing for 90 minutes in an environment of 150 ° C., the surface was roughly polished with a polishing machine LEO600-F4L-BME manufactured by Mizuguchi Seisakusho. Thereafter, finish polishing was performed with SZC manufactured by Mizuguchi Seisakusho to obtain a developing roller base material on which a vulcanized rubber layer was formed.

  Next, a photomask having the same shape as that of Example 1 was prepared, and the substrate for developing roller was irradiated with laser by an excimer laser processing apparatus to form a photomask-like shape pattern on the surface of the substrate.

  Next, 2.5 parts by weight of Mitsui Chemicals Polyurethane Isocyanate D170N and Ketjen Black EC Ketjen Black EC 0.03 part by weight are added to 100 parts by weight of butyl acetate. A coating solution was prepared by stirring for 30 minutes. The obtained coating liquid was impregnated with a surface treatment-treated developing roller substrate, and further baked at 150 ° C. for 2 hours to obtain a developing roller of Comparative Example 1.

<Comparative example 2>
Epichlorohydrin rubber Hydrin T3106 manufactured by Nippon Zeon Co., Ltd. was extruded on the outer periphery of a 6 mm diameter metal shaft to a thickness of 3 mm. Then, after vulcanizing by storing for 90 minutes in an environment of 150 ° C., the surface was roughly polished with a polishing machine LEO600-F4L-BME manufactured by Mizuguchi Seisakusho. Thereafter, finish polishing was performed with SZC manufactured by Mizuguchi Seisakusho to obtain a developing roller base material on which a vulcanized rubber layer was formed.

  Next, to 100 parts by weight of butyl acetate, 2.5 parts by weight of Mitsui Chemicals Polyurethane Isocyanate D170N, Ketjen Black Ketjen Black EC 0.03 part by weight, Nippon Shokubai Co., Ltd. acrylic filler MA1010 2 parts by weight are added. Then, it was stirred for 60 minutes at 120 rpm with a roll mill to prepare a coating solution. The obtained coating solution was coated to a film thickness of about 10 μm with a spray coater and baked at 150 ° C. for 2 hours to obtain a developing roller of Comparative Example 2.

The obtained developing rollers of Examples 1 to 4 and Comparative Examples 1 to 2 were set on IPSIO-C310 manufactured by Ricoh Co., Ltd., and the presence or absence of toner fixation, background staining, and halftone unevenness was confirmed by the following evaluation procedure. .
An evaluation procedure and an evaluation result are shown below.

<Evaluation procedure>
(1) Toner fixation In an environment of a temperature of 30 ° C. and a humidity of 80%, 5000 sheets were run in the white sheet durability single sheet intermittent mode, and the number of vertical white stripes in the halftone image was confirmed.
Evaluation was performed based on the number of confirmed white stripes, with 0 being “◯”, 1 being “Δ”, and 2 or more being “x”. The results are shown in Table 1.

(2) Soil stain The amount of toner on the photoconductor (image carrier) when running a blank sheet of 5000 sheets in a blank sheet durability single sheet intermittent mode in an environment of a temperature of 30 ° C. and a humidity of 80% and outputting a blank sheet image. The measurement was performed using X-Lite manufactured by Sakata Inx Engineering.
Evaluation was made based on the measured value of L *, where 90.0 or more was “◯”, 88.0-89.9 was “Δ”, and 87.9 or less was “x”. The results are shown in Table 1.

(3) Halftone unevenness In an environment of a temperature of 10 ° C. and a humidity of 15%, 5000 sheets were run in a single blank sheet durability intermittent mode, and density unevenness in a halftone image was observed.
According to the sensory evaluation, a level where there was no density unevenness was indicated as “◯”, a level where there was density unevenness but no problem was indicated as “Δ”, and a level where there was a problem due to density unevenness was indicated as “x”. The results are shown in Table 1.

  As shown in Table 1, by performing image formation using the developing device and the process cartridge including the developing roller of the present embodiment, a good image free from toner fixation, background contamination, and halftone unevenness can be obtained. I understand.

11 Image carrier (photoreceptor)
12 Developing device (Developing means)
13 Developing roller 14 Supply roller 15 Restricting member

JP 2011-123357 A

Claims (9)

A surface processing method for the developing roller of a one-component developing device, comprising at least a developing roller that holds toner on an outer peripheral surface and conveys the toner to a developing region, and a regulating member that regulates the thickness of a toner layer supplied to the developing roller. There,
Applying pressure to the vulcanized rubber layer constituting the surface of the developing roller and compressing and deforming in the thickness direction; performing plasma treatment in a compressed and deformed state; And a step of forming the surface of the developing roller.   2. The developing roller surface processing method according to claim 1, wherein the pressing is performed at a linear pressure of 100 N / m to 250 N / m.   The developing roller surface processing method according to claim 1 or 2, wherein the plasma treatment is performed for 10 to 30 seconds.   4. The developing roller surface processing method according to claim 1, wherein plasma processing is performed using a non-reactive gas. The developing roller of a one-component developing device comprising at least a developing roller that holds toner on an outer peripheral surface and conveys the toner to a developing region, and a regulating member that regulates the thickness of a toner layer supplied to the developing roller,
A developing roller having a concavo-convex structure on a surface of a vulcanized rubber layer constituting a surface of the developing roller, wherein the concavo-convex structure is a ridge-shaped structure having a width of a convex portion of 0.1 to 1 μm. .   5. A developing roller, wherein the concavo-convex structure formed by surface processing by the method according to claim 1 is a ridge-shaped structure having a convex portion having a width of 0.1 to 1 μm.   The vulcanized rubber layer on the surface contains an epichlorohydrin rubber selected from epichlorohydrin-ethylene oxide copolymer and epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer. The developing roller according to claim 5.   8. A developing device comprising at least the developing roller according to claim 5 and a regulating member that regulates a thickness of a toner layer supplied to the developing roller. In a process cartridge that has at least an image carrier and a developing unit that develops an electrostatic latent image with toner on the image carrier to form a visible image, and is detachable from the image forming apparatus main body.
The process cartridge according to claim 8, wherein the developing unit is the developing device according to claim 8.